Dry Carbon Research Articles

Agronomic and physiological characteristics of high yield and nitrogen use efficient varieties of rice: Comparison between two near‐isogenic lines

AbstractIncreasing the application of nitrogen fertilizer is the main approach to increase rice production, but it also brings problems of environmental pollution and increases agricultural production costs. Cultivating high‐yielding and high nitrogen use efficiency (NUE) rice varieties is an important approach to solving this problem. The rice varieties carrying dep1 (dense and erect panicle 1) have both high grain yield and high NUE. However, their plant traits have not been fully explored. In this study, two rice near‐isogenic lines carrying dep1 (NIL‐DEP1 and NIL‐dep1) were grown in paddy fields under 0, 120 and 270 kg N ha−1. We analyzed agronomic traits of panicle type, plant type, leaves and roots, and physiological traits of vascular bundles, photosynthetic rate and carbon and nitrogen transport. The results showed that the NIL‐dep1 exhibited higher grain yield and NUE than NIL‐DEP1, mainly due to the higher spikelet number per panicle, grain filling percentage and dry matter production. Compared with NIL‐DEP1, NIL‐dep1 had improved flag leaf morpho–physiological traits, including erect flag leaves, greater leaf thickness and specific leaf weight, higher root dry weight, root length, root volume and root surface area, and a better canopy structure, as reflected by a lower light interception percent and canopy extinction coefficient, leading to better photosynthetic performance and dry matter production. In addition, NIL‐dep1 exhibited better vascular bundle traits of peduncle and enhanced dry matter, stem carbon and nitrogen translocation during grain filling. In conclusion, NIL‐dep1 had high grain yield and NUE by improved agronomic and physiological traits and increasing carbon and nitrogen translocation during grain filling. These traits mentioned above could be used to select and breed high grain yield with high NUE rice varieties.

Does Faeces Excreted by Moxidectin-Treated Sheep Impact Coprophagous Insects and the Activity of Soil Microbiota in Subtropical Pastures?

Moxidectin (MOX) is used to control helminth parasites in ruminant livestock. It is released through feces and remains in the environment for a long period. This study aimed to evaluate the impact of faeces excreted by moxidectin-treated sheep on soil biodiversity (coprophagous insects, soil microbial biomass, and activity) to establish environment-related guidelines regarding the use of MOX in sheep livestock. The study consisted of two experiments. In the first one, faeces from MOX-treated (subcutaneous dose of 0.2 mg·kg-1 body weight) and nontreated rams were placed on an animal-free pasture field, protected or not against rain, for 88 days. Then, coprophagous insects were captured, identified, and counted, and faeces degradation was evaluated by measuring dry weight and carbon (C) and nitrogen (N) contents over time. Diptera, Hymenoptera, Isoptera, and Coleoptera were equally encountered in faeces from MOX-treated and nontreated animals. Faecal boluses of MOX-treated animals (with higher N content) not protected against rain degraded faster than faecal boluses of nontreated animals (with lower N content). In the second experiment, faeces from nontreated animals were amended with increasing amounts of MOX (75 to 3,000 ng·kg-1 faeces), mixed with soil samples from animal-free pasture (1.9 to 75 ng·kg-1 soil), and incubated in a greenhouse for 28 days. Increasing concentrations of MOX did not prevent the growth of cultivable bacteria, actinobacteria, or fungi in culture media. However, even the lower MOX concentration (1.9 ng·kg-1 soil) abruptly decreased soil microbial biomass, basal respiration, and N mineralization. Thus, the results indicate that faeces excreted from sheep treated with MOX under the experimental conditions of this study are not harmful to the coprophagous insects. However, adding MOX to faeces from drug-free sheep had a negative impact on soil microbial activity and biomass.

Simple Linear Regression (SLR) Model for Re-Bending Behavior of a Non-Crimp Dry Thick Carbon Fiber Fabrics

During manufacturing process, fabric such as the non-crimp dry thick fabric (NCF) is bent and re-bent many times until the fabric takes the desirable shape in the mold. Understanding the behavior of dry NCFs requires conducting experimental bending tests which is expensive due to the cost of the carbon fabrics. This paper aimed to model the bending behavior of NCF using simple Linear Regression Model in which the bending moment force is used as a response to displacement. The data modeled were obtained from testing three samples each sample was tested three consecutive times. A total of nine simple linear regression models were created. These nine models showed strong correlation between bending force and extension. The results also showed that the fabric becomes more flexible when it is subjected to re-bending process. Good performance of these models was confirmed using cross-validation method indicating that all presented models in this study were able to predict the bending behavior of non-crimp dry thick fabric.

Levels of Dry Deposition Submicron Black Carbon on Plant Leaves and the Associated Oxidative Potential

There is a need for monitoring air pollution associated with black carbon (BC) using a passive monitor is required in remote areas where the measurements are absent. In this pilot study, we developed a quantitative method to determine dry deposition submicron BC using dual-wavelength ultraviolet–visible spectroscopy. Furthermore, we measured the levels of dry deposition BC on plant leaves from 30 plant species located in urban Nanjing using the established method. The oxidative potential of BC on plant leaves as passive bio-monitoring samplers was assessed. The concentrations of black carbon (BC) on tree leaves varied from 0.01 to 1.6 mg m−2. Significant differences in levels of BC across leaves from different tree types were observed. The values of oxidative potential in deposited particles of leaf samples were observed to be in the range of 33–46 nmol min−1 mg−1 using the dithiothreitol (DTT) assay and 18–32 nmol min−1 mg−1 using the ascorbic acid (AA) assay, respectively. In comparison, the oxidative potential of BC-dominated mass in water extracts of leaf samples was in the range of 5–35 nmol min−1 mg−1 measured using the DTT assay and 2 to 12 nmol min−1 mg−1 using the AA assay, respectively. We found variations in the levels of OP across the leaves of different tree types were not large, while the levels of OP in terms of BC-dominated mass varied greatly. These results indicate that the established method with dual-wavelength ultraviolet–visible spectroscopy could provide a simple tool to determine submicron BC in plant leaves of the passive monitor.

Dry and Hydrothermal Co-Carbonization of Mixed Refuse-Derived Fuel (RDF) for Solid Fuel Production

The present study aims to test several conditions of the thermochemical pretreatment of torrefaction and carbonization to improve the physical and combustible properties of the Portuguese RDF. Therefore, two different types of RDF were submitted alone or mixed in 25%, 50%, and 75% proportions to dry carbonization processes in a range of temperatures between 250 to 350 °C and residence time between 15 and 60 min. Hydrothermal carbonization was also carried out with RDF samples and their 50% mixture at temperatures of 250 and 300 °C for 30 min. The properties of the 51 chars and hydrochars produced were analyzed. Mass yield, apparent density, proximate and elemental analysis, ash mineral composition, and higher heating value (HHV), among others, were determined to evaluate the combustion behavior improvement of the chars. The results show that after carbonization, the homogeneity and apparent density of the chars were increased compared to the raw RDF wastes. The chars and hydrochars produced present higher HHV and lower moisture and chlorine content. In the case of chars, a washing step seems to be essential to reduce the chlorine content to allow them to be used as an alternative fuel. In conclusion, both dry and wet carbonization demonstrated to be important pretreatments of the RDF to produce chars with improved physical and combustion properties.

Comparison of microalgal hydrochar and pyrochar: production, physicochemical properties, and environmental application.

Microalgal biomass has been considered the third-generation biofuel production feedstock, but microalgae-derived biochar still needs to be thoroughly understood. This study aims to evaluate the production and physicochemical properties of microalgae-derived hydrochar produced by hydrothermal carbonization (HTC) process by comparison with pyrochar produced by dry thermal carbonization (DTC) process for environmental applications. Microalgal biochar was produced with commercially available Chlorella vulgaris microalgae using HTC and DTC processes under various temperature conditions. Pyrochar presented higher pH, ash contents, porosity, and surface area than hydrochar. Hydrochar gave more oxygen-containing functional groups on the surface and higher lead adsorption than pyrochar, making the microalgal hydrochar applicable in soil amendment and various environmental remediations. HTC could be an economically feasible thermochemical process for microalgal biochar production. It can produce hydrochar with high production yield from wet microalgae at low temperatures without a drying process.

Recent increase in sediment dry matter, carbon, and phosphorus accumulation in small boreal lakes with clayey catchments

This study estimated the mass accumulation rates of sediment (MAR), carbon (CMAR), and phosphorus (PMAR) in small Finnish lakes with agricultural clayey catchments over a 25-year period (1986–2011) and compared these with the conditions before major agricultural land use. Twenty-two lakes were cored for recent and reference (pre-disturbance) sediments. The recent sediment section was selected based on the 1986 137Cs fallout peak (TOP), whereas the pre-disturbance section (REF) was selected immediately below the first signs of human-induced erosion. The 50-cm reference section was dated with 14C at both ends. The mass accumulation rates were estimated based on dating, weighing, and chemical analysis for both sediment sections. Furthermore, sediment-penetrating echo soundings were used to estimate the amount of sediment in the whole lake basins. These data were used to examine area-specific loading from clay-rich catchments. The average whole-basin pre-disturbance MAR, PMAR, and CMAR were 62 g m−2 a−1, 0.06 g m−2 a−1, and 4.7 g m−2 a−1, respectively. The corresponding recent rates were 11, 13, and 8-fold (693 g m−2 a−1, 0.79 g m−2 a−1, and 37 g m−2 a−1). In the recent conditions, sediments were generally more minerogenic and MAR, PMAR, and CMAR were higher in lakes with more arable fields in their catchments. Average area-specific suspended sediment load from the catchment for the region (∼39% clayey soils) was approximately 69–137 kg ha−1 a−1 in the undisturbed state and 767–1534 kg ha−1 a−1 in recent conditions based on 100–50% retention. The results demonstrate that the increases in sediment, nutrient, and organic matter accumulation due to agriculture can be several fold over undisturbed state.

Enhancement of the wet carbonation of artificial recycled concrete aggregates in seawater

This study aimed to improve the carbonation efficiency and reduce processing time of recycled concrete aggregates (RCAs). Different liquid mediums were used for wet carbonation and compared with dry carbonation. Reaction kinetics, phase assemblage, microstructure and performance of RCAs and recycled aggregate concrete (RAC) prepared with carbonated RCAs were evaluated. RCAs carbonated under seawater for 10 min achieved >9 % reduction in water absorption and 3 % increase in density, which were more efficient than dry carbonated samples. Compressive strength of RAC prepared with 1-h seawater carbonated RCAs was significantly improved. Formation of ettringite and calcite under wet carbonation increased density and strength by contributing to solid volume, also leading to improved bond strength in interfacial transition zone in RAC. Seawater presents several advantages as a medium for wet carbonation due to its abundant availability, CO2 capture capacity and accelerated hydration and carbonation, thereby enabling rapid improvement of RCA's and resulting concrete formulations' performance.

Changes in Leaf Functional Traits Driven by Environmental Filtration in Different Monsoon Tropical Forest Types

Disturbances have created heterogeneous habitats for secondary and old-growth forests. Under the assumption that ecologically similar species have similar functional traits, numerous studies have attempted to use trait-based approaches to infer the abiotic and biotic factors that drive variations in community composition across different forests. However, the relative importance of these drivers in monsoon forests remains poorly understood. In this study, we randomly selected 86 plots and classified them into three forest types according to environmental factors: 1—secondary forests: secondary forest habitats at high elevation; 2—ecotone forests: general recovery and elevation; and 3—old growth forests: old growth at low elevations. We then compared the species and six leaf functional trait variations across the three forests and assessed their relationships with 15 environmental factors. The results showed that secondary and ecotone forests with a conservative strategy, exhibiting high dry matter content and leaf carbon content, tended to persist in stressful habitats, such as nutrient-poor soil, whereas old growth forests invested in trait values related to rapid resource acquisition with high specific leaf area, leaf nitrogen content, leaf phosphorous content, and leaf potassium content. Species with functional trait values between the secondary, ecotone, and old growth forests had clear signatures of their different strategies to persist in assemblages under distinct and opposite environmental filters. These plots were classified into three forest types according to environmental factors: (1) secondary forest at high elevation; (2) ecotone forests at general elevation; and (3) old growth forests at low elevation. Recovery time and elevation, followed by soil nutrients and light capture, were the most important factors shaping species and functional trait variations across forests. These results have demonstrated that environmental filters select plant species with distinct traits and ecological strategies. Acquisitive traits indicate higher competitive ability and faster resource acquisition for forest species that occur in areas with high soil fertility. Meanwhile, conservative traits promote the resistance of secondary species to environmental stressors in low soil fertility, suggesting that analyzing leaf functional-based trait variations to understand plant ecological strategies along an environmental gradient may improve understanding of forest dynamics in tropical monsoon forests.

Effectiveness of Complex Medical Rehabilitation of Patients with Postthrombophlebitic Syndrome of Lower Extremities and Obesity: a Randomized Clinical Study

INTRODUCTION. The relevance of the development of comprehensive rehabilitation programmes for patients with postthrombophlebitic syndrome (PTPS) is due to the high frequency of disability and a significant reduction in their quality of life. Since obesity and excessive body weight are proven risk factors for the development and progression of chronic vein diseases, weight reduction is one of the important tasks of rehabilitation measures in patients with PTPS and concomitant obesity. AIM. Comparative study of the influence of complex methods of medical rehabilitation, including various methods of laser blood irradiation (supravascular and intravenous), pulse magnetotherapy and dry carbon baths, on the dynamics of indicators of composite body composition according to bioimpedance measurements in patients with postthrombophlebitic syndrome of the lower extremities and obesity. MATERIALS AND METHODS. A randomized prospective study was conducted on the basis of the Department of Medical Rehabilitation of Patients with Somatic Diseases of National Medical Research Center of Rehabilitation and Balneology of the Ministry of Health of Russia. The study included 40 patients with PTS of the lower extremities and accompanying obesity, the average age of which was 58.3 [51.5; 68.0] year), randomized to two groups. The patients of the 1st group received Intravenous laser blood irradiation (ILIB) (“Lazmik”, Russia), impulse magnetotherapy and dry carbon baths, as well as therapeutic gymnastics in the hall. The patients of the 2nd group received a complex that included supravascular laser irradiation of blood (“Azor-2K”, Russia), pulse magnetic therapy, and dry carbon baths, as well as therapeutic gymnastics in the gym. Anthropometric measurements (body mass, malleolar volume) were used for the evaluation of anti-edema and lipolytic effects after a comprehensive course of medical rehabilitation, as well as bioimpedance measurement of body composition (“MEDASS”, Russia). RESULTS. In patients with PTS of the lower extremities and obesity, after carrying out a course of medical rehabilitation using preformed physical factors, including various methods of laser irradiation of the blood (supravascular and intravenous), a significant decrease in body weight indicators was observed (p 0.001), a decrease in BMI (p 0.001), total and extracellular fluid (p 0.001) without significant differences between groups. A significant decrease in the index of fat mass (kg) (p = 0.007) was found in patients of the main group. DISCUSSION. Maintaining a healthy body weight as well as combating obesity are first-line secondary prevention measures recommended for all patients with PTS of the lower extremities. For the control of the dynamics of the composite composition of the body, an effective and sensitive method is the method of bioimpedance measurement, which allows to estimate the reduction of extracellular fluid (anti-flow effect) and fat mass of the body (lipolytic effect). CONCLUSION. The method of bioimpedance measurement, used for the evaluation of the composite composition of the body, showed high sensitivity and allowed to establish the greater effectiveness of the developed complex, which includes ILIB with a wavelength of low-intensity laser radiation (NILI) of 635 nm in reducing fat mass.

Effect of conditions on wet carbonation products of recycled cement paste powder

Wet carbonation is deemed a successful approach to recycling waste concrete powder. Controlling the growth and properties of products in the recycled cement paste powder (CPP) is highly dependent on the wet carbonation conditions. Therefore, this study aims to examine the effect of wet carbonation parameters on wet carbonation products in CPP. The wet carbonation of CPP resulted in mixed distribution of silica gel and CaCO3 without significant layering on the CaCO3. In contrast, silica gel covered the outside of the CaCO3 in the case of dry carbonation. Increasing the temperature from 25 °C to 80 °C promoted and accelerated the crystallization and growth of amorphous CaCO3, increased the crystallite size of CaCO3 by 1.1–5.1 nm, and favored the formation of aragonite and vaterite; however, it also led to a significant crystal defect and/or distortion within CaCO3. Higher temperatures also promoted silica gel formation and increased its polymerization degree by 68.2%. On the other hand, increasing the CO2 flow rate from 3 L/min to 5 L/min facilitated the crystallization and growth of CaCO3 and contributed to the increase in the crystallite size of CaCO3 by 3.0–6.6 nm. Higher CO2 flow led to the incorporation of aluminum into silica gel and resulted in the transformation of its gel pores into capillary pores. The findings of this study contribute to a better understanding of the best experimental parameters to achieve a more efficient and effective concrete waste recycling process.

Dry matter dynamics and carbon flux along riverine forests of Gori valley, Western Himalaya

IntroductionRiverine forests in the Himalaya represent a biodiverse, dynamic, and complex ecosystem that offers numerous ecosystem services to local and downstream communities and also contributes to the regional carbon cycle. However, these forests have not been assessed for their contribution to dry matter dynamics and carbon flux. We studied these parameters along three classes of riverine forests in eastern Uttarakhand, dominated by Macaranga, Alnus, and Quercus-Machilus forest.MethodsUsing volume equations, we assessed tree biomass, carbon storage, and sequestration in the study area.ResultsThe total standing tree biomass in Macaranga, Alnus, and Quercus-Machilus forest ranged from 256.6 to 558.1 Mg ha−1, 460.7 to 485.8 Mg ha−1, and 508.6 to 692.1 Mg ha−1, respectively. A total of 77.6–79.6% of vegetation biomass was stored in the aboveground biomass and 20.4–22.4% in belowground plant parts across the riverine forests. The carbon stock in Macaranga forest ranged from 115.5 to 251.1 Mg ha−1, in Alnus forest from 207.3 to 218.6 Mg ha−1, and in Quercus-Machilus forest from 228.9 to 311.4 Mg ha−1. The mean annual litterfall was accounted maximum for Quercus-Machilus forest (5.94 ± 0.54 Mg ha−1 yr.−1), followed by Alnus (5.57 ± 0.31 Mg ha−1 yr.−1) and Macaranga forest (4.67 ± 0.39 Mg ha−1 yr.−1). The highest value of litterfall was recorded during summer (3.40 ± 0.01 Mg ha−1 yr.−1) and the lowest in winter (0.74 ± 0.01 Mg ha−1 yr.−1). The mean value of net primary productivity and carbon sequestration was estimated to be highest in Quercus-Machilus forest (15.8 ± 0.9 Mg ha−1 yr.−1 and 7.1 ± 0.9 Mg C ha−1 yr.−1, respectively) and lowest in Alnus forest (13.9 ± 0.3 Mg ha−1 yr.−1 and 6.1 ± 0.3 Mg C ha−1 yr.−1, respectively).DiscussionThe results highlight that riverine forests play a critical role in providing a large sink for atmospheric CO2. To improve sustainable ecosystem services and climate change mitigation, riverine forests must be effectively managed and conserved in the region.

Isolating the effects of land use and functional variation on Yucatán's forest biomass under global change

Tropical forests hold large stocks of carbon in biomass and face pressures from changing climate and anthropogenic disturbance. Forests' capacity to store biomass under future conditions and accumulate biomass during regrowth after clearance are major knowledge gaps. Here we use chronosequence data, satellite observations and a C-cycle model to diagnose woody C dynamics in two dry forest ecotypes (semi-deciduous and semi-evergreen) in Yucatán, Mexico. Woody biomass differences between mature semi-deciduous (90 MgC ha−1) and semi-evergreen (175 MgC ha−1) forest landscapes are mostly explained by differences in climate (c. 60%), particularly temperature, humidity and soil moisture effects on production. Functional variation in foliar phenology, woody allocation, and wood turnover rate explained c. 40% of biomass differences between ecotypes. Modeling experiments explored varied forest clearance and regrowth cycles, under a range of climate and CO2 change scenarios to 2100. Production and steady state biomass in both ecotypes were reduced by forecast warming and drying (mean biomass 2021–2100 reduced 16–19% compared to 2001–2020), but compensated by fertilisation from rising CO2. Functional analysis indicates that trait adjustments amplify biomass losses by 70%. Experiments with disturbance and recovery across historically reported levels indicate reductions to mean forest biomass stocks over 2021–2100 similar in magnitude to climate impacts (10–19% reductions for disturbance with recovery). Forest disturbance without regrowth amplifies biomass loss by three- or four-fold. We conclude that vegetation functional differences across the Yucatán climate gradient have developed to limit climate risks. Climate change will therefore lead to functional adjustments for all forest types. These adjustments are likely to magnify biomass reductions caused directly by climate change over the coming century. However, the range of impacts of land use and land use change are as, or more, substantive than the totality of direct and indirect climate impacts. Thus the carbon storage of Yucatan's forests is highly vulnerable both to climate and land use and land use change. Our results here should be used to test and enhance land surface models use for dry forest carbon cycle assessment regionally and globally. A single plant functional type approach for modeling Yucatán's forests is not justified.

Planting time and stand density effect on radiation interception and use efficiency of maize and sunn hemp intercropping in semi-arid South Africa

Solar radiation must be efficiently utilised to enhance dry matter accumulation and carbon sequestration capacity within dryland agroecosystems. The study evaluated the effects of sunn hemp (Crotalaria juncea L.) intercropping time and stand density on radiation interception and radiation use efficiency (RUE) in a maize-based system. Field experiments were conducted under the in-field rainwater harvesting (IRWH) technique for two consecutive growing seasons, 2019/20 and 2020/21. Radiation interception and productivity were measured and calculated for maize and sunn hemp, sole and intercrops. The intercrops were identified by the sunn hemp intercropping times [simultaneous with maize planting (P1), at V15 maize growth stage (P2), at R1 maize growth stage (P3)] and stand densities [16 plants m–2 (D1-low), 32 plants m–2 (D2-medium), 48 plants m–2 (D3-high)]. Total radiation interception was calculated using a row-crop radiation transmission (RCRT) model from strip width of component crops, extinction coefficient (k), plant height, and leaf area index (LAI) measurements taken throughout the growing season. The results showed that the LAI of sunn hemp was high when intercrop was planted simultaneous with maize planting and at 48 plants m–2. The overall k for the sole sunn hemp (SSH) cropping system was 0.37. The correlations (r2) between the modelled and measured fractions of photosynthetic active radiation (PAR) in simultaneous maize planting, V15 maize growth stage, and R1 maize growth stage intercropping treatments were 0.87, 0.97 and 0.93, respectively. Simultaneous planting of sunn hemp intercrop with maize captured the most growing season PAR of 798.70 MJ m–2 and had the highest RUE of 1.42 g MJ−1. These results suggest that intercropped sunn hemp planted simultaneously with maize would help to increase production through the more efficient use of solar radiation. Optimising planting time and density can help plan the planting time to increase radiation utilisation in maize/sunn hemp intercropping systems.

Achieving clean production with nanostructured coated milling tools dry machining low carbon steel

The advancement of clean production using nanostructured materials in subtractive manufacturing processes has focused on replacing the use of liquid lubrication with solid lubricants coated to conventional cutting tools machining low carbon steel (∼0.2 wt % carbon). However, little is known about the wear mechanisms that dominate such tools when coated with functional graded nanostructured coatings. The present study follows an international standard for characterizing such wear (ISO 8688) but uses advanced measurement techniques such as x-ray fluorescence technology to measure the diffusion of chemical species from tool to workpiece and vice versa, that contributes to tool wear with the view to enhance the principles of cleaner production. The results show that when commercially-available tools coated with the appropriate functionally graded industrial coating, diffusion does not take place and creates an effective chemical barrier during machining. The experimental methods used in the study include machining workpieces using a CNC milling machine, tachometer for measuring spindle speed, dynamometer for measuring cutting forces, infra-red camera for measuring cutting temperatures, chemical species diffusion wear using x-ray fluorescence detector, and an optical microscope for measuring tool wear. Coupled with the physical measurement of wear, it is concluded that mechanical wear dominates the milling of a low carbon steel and that thermal properties of the coatings do not correlate with such wear. It is also concluded that flank wear as a function of volume of workpiece removed and machining duration (machining index) is a sound method for assessing the transition of the stages of wear during clean machining operations. The present study not only has implications for the design of better cutting tools, but also advances dry machining processes that eliminate the use of liquid lubricants making subtractive production processes cleaner. The main conclusions drawn from this study show that coated tools have a longer life under dry conditions compared to uncoated tools and that there is no correlation between coating properties and tool wear. Diffusion of chemical species into the cut chips did not occur because of the lack of thermally induced chemical wear of the cutting tool and that wear is caused by the gradual erosion of the flank face due to the chip abrading the cutting tool.

FEA and experimental ultimate burst pressure analysis of type IV composite pressure vessels manufactured by robot-assisted radial braiding technique

Composite pressure vessels (CPVs) are lightweight and high-strength containers that can be used for the storage of compressed gases, including hydrogen. While hydrogen is a promising alternative energy source, storage of hydrogen comes with its significant challenges which requires a need for the efficient production of CPVs. Most commonly, CPVs are manufactured using filament winding technology. Due to the rise in the need for pressure vessels, there is a need for alternative high-throughput manufacturing techniques. Braided, in comparison to filament winding, has a high throughput and is less research manufacturing technology for CPVs. In this study, the applicability of braiding for the manufacturing of CPV is researched. Two types of 2D braids, namely the conventional and unidirectional, braiding were studied for their application in such structures, 24K and UD tanks, respectively. Dry carbon fiber (T700S – 24K) and HDPE liner were used to manufacture two different types of composite pressure vessels (CPVs), by robot-assisted radial braiding technique. After the preform of the braiding process was finished, CPVs were cured with a vacuum infusion process (VIP) by using a mold system. Produced braided CPVs were subjected to a hydrostatic burst test in order to determine their ultimate burst pressure point. Finite element analysis (FEA) was used to optimize and correlate experimental burst pressure test results. Ansys ACP was utilized to design composite structures by dividing both tanks’ domes into sub-sections. Results suggest that the experimental burst pressure test of 24K and UD tanks were identified as 200 bar and 150 bar, respectively. UD vessel ruptured close to the dome, whereas the 24K fracture point was located in the center of the dome. UD braided CPV was shown to have a smaller apparent burst deformation (rupture) scale than 24K CPV. In comparison to 24K, the UD braided CPV is 5.7% lighter and requires 20.9% less carbon fiber in production. FEA results were consistent with experimental results in terms of the burst pressure point. For both 24K and UD, the fiber failure starts at the point where the cylinder section and boss system are connected under pressure, and fiber failures continue to progress steadily as the pressure increases.

Catalytic Conversion of Oil in Model and Natural Reservoir Rocks

The catalytic activity of metal oxides in the processes of low- and high-temperature oxidation (LTO and HTO, respectively) of oil was studied on model systems consisting of oil-saturated quartz sand with additives of Al2O3, Cr2O3 and MgO using thermal analysis methods. The used additives were shown to shift the LTO and HTO processes to the low-temperature region. The catalytic activity of a natural reservoir carbonate rock without and with water was studied. This study established that at room temperature in dry carbonate rock, the oil components undergo dealkylation and polycondensation of aromatic fragments for a week. In the presence of water, the polycondensation processes are suppressed, and the cracking of resin and asphaltene occurs. The cracking reactions lead to a decrease in the content of heteroatoms in resins and asphaltenes.

61. Adding biochar to the diet of post-weaned piglets increases the dry matter and carbon content of faeces

61. Adding biochar to the diet of post-weaned piglets increases the dry matter and carbon content of faeces

A comparative study of ethylenediamine tetraacetic acid induced gas-solid and liquid-solid accelerated carbonation for enhancement of steel slag aggregates

Accelerated carbonation is an effective technique to enhance the hydration reactivity and volume stability of steel slag aggregates (SSA). However, due to limitations in CO2 transport and carbonation kinetics, carbonation of SSA is frequently carried out using pure CO2 under high pressures. In this study, carbonation under 10% CO2 concentration and ambient temperature and pressure was employed to treat SSA. To accelerate the carbonation of SSA, ethylenediamine tetraacetic acid (EDTA)-induced gas–solid (dry) and liquid–solid (wet) carbonation processes were proposed. Effect of EDTA on the physical and mechanical properties and microstructure of carbonated SSA; and the performance of resulting concrete with a selected mix design were examined. Dry carbonation of SSA, prior to which EDTA was sprayed on the surface of SSA, resulted in a denser carbonated layer and consequently higher specific gravity compared to uncarbonated SSA. Concrete samples involving carbonated SSA, on which 0.1 mol/L EDTA was sprayed at 50% of water absorption mass of SSA, followed by carbonation curing for 24 hrs, revealed 24% increase in strength and 75% reduction in expansion when compared to those containing uncarbonated SSA. Wet carbonation of SSA, during which CO2 was injected into SSA-EDTA solution, promoted both carbonation and hydration of SSA, especially in 0.2 mol/L EDTA solution, resulting in the consumption of periclase and enabling the formation of brucite. While strength improvement was not obvious in the presence of brucite that weakened the interfacial transition zone (ITZ) of concrete, expansion was further reduced by the reduced periclase in SSA. Comparatively, EDTA-induced dry carbonation was more effective and required only 0.4 kg EDTA per tonne of SSA.

Total recycling of concrete waste using accelerated carbonation: A review

Our world is facing critical environmental challenges due to the overexploitation of natural resources and the extensive release of CO2. Meanwhile, huge amounts of concrete waste are generated due to accelerated urbanization and redevelopment. Carbonated concrete waste can thus both be used as alternative materials to aggregates and cement, and a carbon sink to reduce CO2 emission. In this paper, different carbonation approaches and their modified techniques to treat recycled coarse aggregates (RCAs), recycled concrete fines (RCFs), and recycled concrete powders (RCPs) are critically reviewed and discussed. The results suggest that carbonation effectively strengthens RCAs by densifying microstructures and improving physical properties through the precipitation of calcium carbonate (Cc) that fills the pores. Meanwhile, the carbonation reaction also develops surface reactivities on the recycled aggregates due to silica gel and Cc formation, which is particularly beneficial for RCFs because of the high surface area. Re-structuring and re-activation of RCPs through carbonation transforms the waste hydrated cement powders into novel supplementary cementitious materials. In addition to wet carbonation, which has a higher efficiency than dry carbonation, other modified carbonation techniques with the addition of limewater, magnesium ions, ammonium ions, and the use of elevated temperatures are found to produce RCAs/RCFs/RCPs with better qualities, and facilitate the formation of other high-value products such as nano-silica gel, micro-fiber, and vaterite, etc. Apart from their practical uses in conventional concrete, potential applications of the carbonation products in ultra-high-performance concrete, automated construction, and self-cleaning concrete were also briefly introduced. More importantly, the key issues in upscaling the carbonation technologies and limitations in current research are pointed out. Overall, carbonation could not only facilitate the re-circulating of concrete waste but also help reduce CO2 emissions and achieve carbon neutrality by permanently sequestrating CO2.