Volume Of Water Research Articles

Congo River: Analysis of suspended sediment flux in a multichannel megasystem in Central Africa

Tropical mega rivers play a crucial role in transferring water and sediment to the oceans. The Congo River is the second largest in the world by volume of water, playing a significant role in the export of fresh water and sediment from the continent to the Atlantic Ocean. This paper aims to analyze the variability of the suspended sediment flux of the Congo River between 2005 and 2018. Suspended Sediment Concentration (SSC), water discharge and water level data were used at the Brazzaville station, which represents 97% of the basin area, and precipitation data for the entire basin. Solid discharge, specific sediment yield and denudation rate of the basin were estimated. The estimated water discharge was 41 268 m³.s-1 for the period between 1947 and 2023, with a bimodal river regime with a flood peak in December and a secondary peak in May. The mean annual SSC estimated for the Congo River was 27.20 mg.L-1. A moderate (r = 0.48) and weak (r = -0.26) correlation was observed between SSC and precipitation, and SSC and water level, respectively, possibly influenced by the basin's terrain characteristics. During the year, the Congo River transfers 33.66 × 106 ton.year-1 of sediment to the ocean, has a specific sediment yield of 9.62 ton.km-2.year-1 and a very low denudation rate (3.37 mm.ky-1).

Enhancing the efficiency of solar-powered water distillation units by utilization of waste heat

ABSTRACT Thermal water desalination is based on the evaporation and condensation of water, and such a process consumes a lot of energy, which lowers the economy of the process for commercial water desalination. The objective of this research is to improve the desalination energy efficiency of a novel domestic water desalination unit, which is based on thermal desalination, and this is done via utilization of the waste heat in the generated steam and reducing the operating costs. The distillation process begins with solar-powered evaporation of the salty water in the evaporator, followed by condensation of the generated water vapor coming from the evaporator over the cross-flow heat exchangers located in the condenser, which preheats the incoming saline water from the saltwater tank before it enters the evaporator. To assess the system's performance, comprehensive measurements are taken, including the electrical energy output from the PV panels and the volume of the output distilled water. Notably, the energy efficiency of the distillation is defined as the ratio of the heat energy gained by the distilled water, i.e. collected at the end of the day, to the electrical energy input to the electric heater, and it is found to be, on average, 82%.

DETERMINATION OF WATER TARIFFS PDAM TIRTA PEUSADA EAST ACEH, INDONESIA

The determination of water tariffs by Perumda Tirta Peusada in East Aceh District has led to community dissatisfaction due to tariffs that are considered unfair and do not reflect the quality of service received, as well as unclear water distribution. This issue potentially contains elements of gharar (uncertainty) in the water sale and purchase transaction, which is contrary to the principles of Islamic law. This research uses descriptive analysis method with a case study approach and qualitative research, by collecting data through interviews and literature study to analyse the implications of water tariff setting at Perumda Tirta Peusada in the context of sharia economic law. The determination of water tariffs by Perumda Tirta Peusada in East Aceh Regency contains elements of gharar in the context of sharia economics, because the tariff charged is not in accordance with the volume of water consumed by customers. Customers are still charged for 10 cubic metres even though their water usage is less than that amount, creating uncertainty in the transaction. In addition, frequent water distribution disruptions and supply instability further exacerbate this problem, as customers pay for services they do not receive as expected. This practice goes against the principles of transparency, fairness, and clarity advocated in Islamic law. Therefore, Perumda Tirta Peusada needs to improve its tariff policy and the quality of water distribution to ensure that water transactions are more fair, transparent, and in accordance with sharia principles.

Water and Oil Volume Measurement Using UV–Visible Spectroscopy

Fluid saturation in relative permeability experiments is typically determined by volumetric or gravimetric measurements, as well as in-situ saturation monitoring (ISSM). Gravimetric measurements tend to have larger error due to grain loss. The conventional volumetric method used can be a challenge because produced volumes for oil and water must be separated and measured manually. ISSM method is also a costly technique. In this study, an UV–visible spectroscopy was used to continuously and cost effectively measure oil and water volumes. A water-oil unsteady state relative permeability was performed to investigate the feasibility of calculating oil and water volumes using UV–visible spectroscopy. UV–visible spectroscopy is a quantitative technique in analytical chemistry to determine concentrations of known solutes. A UV–visible spectroscope was located in the flow line immediately after the core holder and used to quantify fluid volumes (oil and water) produced from a core sample during unsteady state relative permeability study. A volumetric separator was also used to compare production volumes obtained from UV–visible spectroscope. The relative permeabilities were calculated using JBN method from both volumetric and UV-visible spectroscope measurements and then history matched with Sendra (PRORES AS). The final oil volume produced, oil and water relative permeability curves obtained from UV–visible spectroscope measurements were in good agreement with volumetric measurements. The Corey relative permeability curves simulated from Sendra also were closely matched with analytical relative permeability curves obtained using volume measurements from volumetric and UV–visible spectroscope data. Nuclear Magnetic Resonance (NMR) on post relative permeability experiment was also in good agreement with UV–visible spectroscope measurement. UV–visible spectroscopy was also used to measure the breakthrough time of the injected fluid. Breakthrough time estimated using in-line UV–visible spectrophotometer was 0.634 PVI compared to 0.617 and 0.673 PVI from pressure data and volumetric observations.Graphic

Evaluation of the Hydrological Response of Nature-Based Solutions (NBS) in Socio-Economically Vulnerable Tropical Urban Settlements: A Case Study in La Guapil, Costa Rica, Under Climate Change Scenarios

Urbanization increases the number of impervious surfaces in watersheds, reducing infiltration and evapotranspiration, which increases runoff volumes and the risks of flooding and the pollution of water resources. Nature-based solutions (NBS) mitigate these effects by managing water volume and quality, restoring the hydrological cycle, and creating sustainable livelihoods that can promote socioeconomic equity by providing green space. In light of the aforementioned information, this study analyzes the hydrological response of NBS in La Guapil, a densely populated and socioeconomically vulnerable area of Costa Rica with approximately 80% impervious surfaces, focusing on their effectiveness in stormwater management and improving hydrological conditions. Field data from the study area’s storm drainage system, as well as hydrological analyses, were collected and processed to evaluate RCP8.5 climate change scenarios using the Clausius–Clapeyron (CC) relationship. Three scenarios were proposed: (1) the “status quo”, reflecting current conditions, (2) green roofs and green improvements, and (3) detention ponds and green improvements, evaluated using the SWMM, with the latter scenario also using the Iber model. Simulations showed that Scenario 2 achieved the greatest reduction in peak flow (53.74%) and runoff volume (57.60%) compared to Scenario 3 (peak: 28.37%; volume: 56.42%). Both scenarios demonstrate resilience to climate change projections. The results of this study provide a foundation for further research into NBS in Costa Rica and other comparable regions.

Geoinformation monitoring of the condition of rice fields in Giang Province (Vietnam) according to multispectral ERS data and field spectroradiometering

The spatial distribution of areas of territory used for agricultural work is of great importance for the development of measures for managing territories and planning the rational use of land and water resources. As a result of the high development of land and its use for agricultural production, timely assessment of both the condition of soils and the growing season of crops in the fields plays an important role. Since in the conditions of the study area it is possible to choose the timing of sowing, growing and harvesting, spatial data on the location of fields for growing rice can be used to estimate the volume of water consumed for its cultivation and develop a crop rotation model for different volumes of available water based on the level of water reserves of the main crop. source. Geoinformation classification of Earth remote sensing data and the use of spectral indices can be used to monitor the dynamics of rice crop formation under existing conditions. Refinement of the results of geoinformation processing of satellite images is carried out using field standardization methods, including photo standardization, showing the real value of reflected energy during large-scale photography, and spectroradiometry, which makes it possible to determine the characteristics of the reflected energy by these objects in various spectral ranges. The results obtained made it possible to obtain statistical data on the values of the area of plots based on 4844 measurements; the average values of the area of plots were established – 0.447, standard deviation – 0.309, maximum area – 5.84 hectares, minimum 0.02 hectares. The obtained statistical results make it possible to determine on average the estimated number of plots in the territory of An Giang province, which is 442 thousand fields. Thus, when deciphering images of rice fields on satellite images, local geoinformation cartographic layers of such fields are developed, taking into account the actual characteristics and stage of plant vegetation, as well as the stage of harvesting and the stage of tillage.

Hydroponic System with Integrator Modified on PI Controller for Nutrient and Water Regulation

— This study developed a hydroponic control system to regulate nutrient concentration (PPM) and water volume using a Proportional-Integral (PI) controller. The PI controller was chosen for its simplicity and effectiveness in systems that do not require fast response times. A trial-and-error method was used to tune the Kp and Ki values, which were implemented in an ATMega328 microcontroller. The system consists of one AC pump and two DC pumps: DC Pump-1 controls the PPM by supplying liquid fertilizer, while DC Pump-2 regulates the water volume. The results showed that modifying the PI controller with an integrator limitation improved performance. For PPM control, a limit of 13000 with Kp = 2 and Ki = 0.01 resulted in a 0.5% error, 56.8-second rise time, and a 4.8% overshot. For water level control, a limit of 12000 with Kp = 100 and Ki = 0.16 yielded a 3.25% error, 2% overshot, and a 65.4-second rise time. The test results demonstrated that the use of AB Mix can be reduced by up to 26% compared to a conventional PID, with an initial PPM value of around 350.

Assessment of Age-Related Microstructure Changes in Thigh Skeletal Muscle Based on Neurite Orientation Dispersion and Density Imaging.

Neurite orientation dispersion and density imaging (NODDI) could offer information about the morphological properties of tissue. Diffusion microstructure imaging has been widely used, but the applicability of NODDI in skeletal muscle imaging remains to be explored. To evaluate microstructure parameters variations in skeletal muscle as indicators of age-related changes. Prospective, cross-sectional. A total of 108 asymptomatic volunteers, divided into three age groups: 20-39 years (N = 34), 40-59 years (N = 40), and over 60 years (N = 34). 3-T, three-dimensional (3D) gradient echo sequence. T1-weighted imaging, T2-weighted imaging with spectral adiabatic inversion recovery, and NODDI were used to image the thigh skeletal muscles. Four thigh skeletal muscle groups were analyzed, including bilateral thigh quadriceps femoris and hamstrings. The microstructure parameters included orientation dispersion index (ODI), intra-myofibrillar water volume fraction (V-intra), free-water fraction (V-csf), fractional anisotropy (FA), and mean diffusivity (MD). These parameters were quantified using NODDI images and compared among different age, body mass index (BMI), and skeletal muscle index (SMI) subgroups. Segmentation measurement reliability was assessed using a two-way mixed intraclass correlation coefficient (ICC). Shapiro-Wilk tests were used to assess data distribution. Kruskal-Wallis and Mann-Whitney U tests were used to compare ODI, V-intra, V-csf, FA, and MD values among different age, BMI, and SMI subgroups. The Spearman correlation coefficient was utilized to assess the strength of the correlation between the age and microstructure parameters, as well as between age and SMI. Additionally, Bonferroni post hoc tests were conducted on microstructure parameters that exhibited significant differences across various age groups. A P-value <0.05 was considered statistically significant. Significant differences in ODI, V-csf, FA, and MD values were observed among age, BMI, and SMI subgroups. NODDI may be used to reveal information about microstructure integrity and local physiological changes of thigh skeletal muscle fibers in relation to age. 2 TECHNICAL EFFICACY: Stage 2.

Larval development of two syntopic amphibian species (Bombina orientalis, Anura, Bombinatoridae and Dryophytes japonicus, Anura, Hylidae) living separately or jointly in the Far East, based on the results of laboratory studies

Competition is known to render significant impacts both on population dynamics and community structure. As it has traditionally been believed, Dryophytes japonicus larvae inhibit Bombina orientalis larvae when cohabiting. The study is devoted to the study of the influence of these species on the development of each other in experimental conditions. The larvae were grown before metamorphosis in three variants: with single maintenance, together with conspecifics at different densities, as well as with the joint maintenance of individuals of the two species. When kept alone, B. orientalis larvae, in comparison with D. japonicus, are characterized by a higher survival rate (100% vs. 85%), a shorter duration of larval development and a longer body length of individuals during the period of metamorphosis. With an increase in the duration of larval development, the size of D. japonicus juveniles is increased. There are no differences in survival rate when growing larvae of each species at different densities. The duration of larval development varied significantly in different experimental groups. In both species, the duration of development correlated with the initial density per unit volume of water and per unit area of the bottom. With increasing density, the length and mass of the larvae are decreased. The bottom area renders a greater impact on the duration of larval development, as well as the length and body weight of B. orientalis juveniles than the volume of water. According to the results of regression analysis, with an increase in the initial planting density of B. orientalis by 100 specimens per square mof the bottom, the duration of larval development was increased by 4.7 days, the body length decreased by 0.83 mm, and the weight dropped by 0.06 g. The volume of water has a greater influence on the same indicators of larval development of D. japonicus. With an increase in the initial density by 1 specimen per water liter, the duration of larval development of D. japonicus was increased by 11.7 days, the body length decreased by 0.37 mm, and the weight dropped by 0.07 g. When the larvae of the two species were grown together with an increased proportion of one of them, a negative impact was observed neither on the survival nor the development, nor the growth of the other species. On the contrary, with an increased number of conspecifics in the container due to a decrease in the number of individuals of the other species, the development and growth of larvae of the former species was inhibited. Thus, in the laboratory conditions, no noticeable interspecific competition was observed between the larvae of B. orientalis and D. japonicus. The authors suggest that a successful coexistence of these two species is associated with pronounced intraspecific competition in each of them, this previously noted for other animal taxa.

Three-Dimensional Printing of Bioinspired Hierarchical Structures for Enhanced Fog Collection Efficiency in 3D Space via Vat Photopolymerization

Collecting fog water is crucial for dry areas since natural moisture and fog are significant sources of freshwater. Sustainable and energy-efficient water collection systems can take a page out of the cactus’s playbook by mimicking its native fog gathering process. Inspired by the unique geometric structure of the cactus spine, we fabricated a bioinspired artificial fog collector consisting of cactus spines featuring barbs of different sizes and angles on the surfaces for water collection and a series of microcavities within microchannels inspired by Nepenthes Alata on the bottom to facilitate water flowing to the reservoir. However, replicating the actual shape of the cactus spine using conventional manufacturing techniques is challenging, and research in this area has faced a limitation in enhancing water-collecting efficiency. Here, we turned to 3D printing technology (vat photopolymerization) to create bio-mimetic fog collectors with a variety of geometric shapes that would allow for the most effective conveyance and gathering of water. Various barb sizes, angles between each barb in a single array, spine and barb arrangements, and quantity of barbs were tested experimentally and numeric analysis was carried out to measure the volume of water collected and optimize the mass rate. The result shows that optimal fog collection is with a mass flow rate of 0.7433 g/min, with Li = 900 μm, θ = 45°, ϕ = 90°, Nb = 2, and Ns = 5. This study presents a sustainable and ecologically sound method for efficiently collecting humid air, which is expected to be advantageous for the advancement of future-oriented fog-collection, water-transportation, and separation technologies.

Individualized metering and the influence of other endogenous and exogenous factors on water consumption in social housing

ABSTRACT Individual water metering allows consumers to pay for the water volume actually consumed, promoting the efficient use of water resources. This case study aims to evaluate the impact of consumption billing based on individual water meters in a social housing complex in the city of Joinville, southern Brazil. The residential complex under study consists of 20 four-story buildings with four units per floor, each with a floor area of 40.17 m2. Statistical analyses were conducted in 158 households, whose residents agreed to participate in the interview stage. Data were collected over a period of 1,429 days and until 21 August 2020. The water billing system was initially based on a collective consumption meter, with subsequent apportionment of the consumption charges between the households. An individual billing system was then implemented, using one water consumption meter per household. The impact of individual water billing on the water consumption data from the households in the sample was analyzed using descriptive statistics, Wilcoxon–Mann–Whitney nonparametric test, and Prais–Winsten regression model. The results showed that the water billing system influences the per capita water consumption in the social housing complex under analysis.

Simulating Water Invasion Dynamics in Fractured Gas Reservoirs

The Longwangmiao Formation gas reservoir in the Moxi block of the Sichuan Basin is a complex carbonate reservoir characterized by a low porosity and permeability, strong heterogeneity, developed natural fractures, and active water bodies. The existence of natural fractures allows water bodies to easily channel along these fractures, resulting in a more complicated mechanism and dynamic law of gas-well water production, which seriously impacts reservoir development. Therefore, a core-based simulation experiment was designed for oil–water two-phase flow. Three main factors influencing the water production of the gas reservoir, namely fracture permeability, fracture penetration, and water volume multiple, were analyzed using the orthogonal test method. The experimental results showed that the influences of the experimental parameters on the recovery factor and average water production can be ranked as water volume multiple &gt; fracture penetration &gt; fracture permeability, with the influence of the water volume multiple being slightly greater than that of the other two parameters. It provides a certain theoretical basis for water control of the gas reservoir.

Factors affecting survival and growth of the East Asian common octopus (Octopus sinensis) paralarvae reared from hatching to settlement in upwelling tanks at different scales of mass production

There is an ever-increasing global demand for aquaculture of common octopuses. Rearing technology for paralarvae of the East Asian common octopus (Octopus sinensis) has been recently improved by developing an upwelling rearing system in combination with supplying zoeae of the swimming crab (Portunus trituberculatus) as feed. However, this is still at a laboratory scale (1 kL water volume), and optimal rearing conditions are still unknown. Trials with a pilot large-scale system are here compared with the performance of a successful small-scale system. To investigate optimal rearing conditions for paralarvae, relationships between rearing parameters and paralarval survival and growth were analyzed using the data from 28 experimental laboratory-scale rearing trials of paralarvae conducted in three different research institutes. A large upwelling system was constructed using two adjacent rectangular tanks (8 kL volume each, 16 kL maximum capacity): one containing paralarvae; the other used as a server tank. Two water inflow pipes were installed in the rearing tank to produce steady upwelling. This system produced between 2505 and 4694 settled juveniles over three trials. The survival rate (15, 20, and 64 %) did not differ from the results using small 1 kL systems. Throughout the 28 trials, there was a total yield of 26,213 settled juveniles at a survival rate of 63.8 ± 23.2 % (range 15–96 %). There was no particular factor affecting paralarval survival and growth during the first half of the rearing period (P1). A high water temperature (24.4 °C) improved survival rate during both the total (PT) and second half of the paralarval rearing period (P2), as well as growth rate during PT, when compared to lower water temperature (22.1 °C). The amount of zoeae of P. trituberculatus supplied negatively affected the survival rate during P2 and PT, suggesting that excess food supply may reduce paralarval survival due to nutritional degradation of uneaten zoeae remaining in the rearing tanks. Paralarval size at hatching did not affect the growth rate, but there was a significant positive correlation between hatchling size and size-at-age of reared octopuses. These results indicate that the upwelling system for rearing paralarvae of O. sinensis can be scaled up even using large rectangular tanks by introducing multiple water inflow pipes, and that paralarval survival and growth can be improved by using large hatchlings, a water temperature at 24–25 °C, and a closely monitored optimal supply of healthy zoeae.

Pasta Enriched with De-oiled Sesame and Yellow Pepper Flours: Evaluation of Physicochemical Properties, Protein Quality, and Antioxidant Potential

Valorization of waste as a sustainable food additive to produce value-added products is a recent interest. De-oiled sesame flour (DSF) is underutilized despite its rich protein, fiber, and phenols content. Pasta has a poor nutritional value but is a good vehicle for fortification. Therefore, pasta was enriched with DSF at 10%, 20%, and 30%, in addition to 5% yellow pepper flour (YPF) to improve the taste (S10, S20, and S30, respectively). The enriched pasta was compared to control pasta (S0) made from 100% durum wheat semolina concerning the sensory attributes, cooking quality, physicochemical properties, and microstructure. S20 pasta demonstrated good cooking properties and a texture profile similar to the control, with high sensory appeal. It had the lowest cooking loss (7.60±0.10), gumminess (39.50±5.12 g), and chewiness (0.62±0.09 mJ), the highest water absorption and volume expansion (101.30±1.27% and 295.00±7.07%), a shorter cooking time (10.05±0.71 min) and hardness (73.00±5.66 g), with a moderate cohesiveness (0.54±0.03) (p<0.05). DSF increased the protein content of the enriched pasta significantly compared to the control (14.40±0.57g to 16.90±0.57g versus 13.20±0.28 g/100g). Besides, the protein quality was improved by adding 20% DSF: The essential amino acid index increased from 62.76±0.05% to 73.11±0.95% in S20 (p<0.05). Furthermore, the antioxidant activity was increased from 1.67±2.12% (control) to 28.75±1.53% (S20) (p<0.05). Besides, iron, calcium, and zinc were increased considerably (p<0.05). De-oiled sesame flour at 20% (S20) is a promising additive for pasta producers that offers acceptable physical changes, high nutritional value, and enhanced protein quality compared to control.

Analysis of Nanobubble-oxygenated Water for Horticultural Applications

The theoretical properties of nanobubbles (NBs), such as a negative surface charge and large interfacial surface area, allow for highly efficient gas transfer and stagnation time in water and may reduce the surface tension of NB-treated water sources. These properties make NBs unique candidates for addressing issues like root zone oxygen deficiency, common in conventional and hydroponic crop production. Therefore, the objectives of this research were to confirm the presence of NBs in treated water and determine how time and temperature affect dissolved oxygen (DO) retention in NB-oxygenated water. Two membrane-based NB injection systems were compared with a standard method of aeration (aquarium air stone) and untreated potable water to determine the effect of NB oxygenation on DO retention time and nanoscopic particle size and concentration of potable water sources. NB oxygenation of potable water generally resulted in a greater number of nanoparticles detected compared with untreated potable water. NB oxygenation increased initial levels of DO in potable water when compared with the standard air stone. NB oxygenation failed to increase DO retention time compared with a standard air stone, regardless of water temperature. NB oxygenation remains a method of efficiently oxygenating large volumes of water, although the NBs investigated in the study did not increase DO retention in a potable water source.

Optimal design of solar collector network in novel hybrid desalination plant

In this study, a new hybrid system for producing fresh water from seawater using solar energy is proposed. It suggests a modified and optimized approach to reduce the reliance on fossil fuels and decrease pollutants by also harnessing solar energy. The system includes flat-plate solar collectors, a multi-effect distillation through thermal vapor compression (MED-TVC) desalination unit, a pump, and a boiler. The flow rate of the produced fresh water and the specific cost of generating fresh water volume were considered objective functions and the system was optimized using as evolutionary algorithm. The algorithm was employed to determine 12 design variables. Series, parallel, and series-parallel configurations were examined as layouts for flat plate collectors. The results indicated that the series-parallel arrangement was the most effective layout for the collectors. The modeling was carried out for the city of Bandar Abbas in Hormozgan Province, Iran. The production of fresh water in series-parallel mode has increased by 12.15% and 27.83%, respectively, compared to the parallel and series configurations at the ideal point. An assessment of the results suggests that choosing the design point within the flow rate range of 4.19 L/s to 4.65 L/s is preferable.

The influence of astronomical tide phases on urban flooding during rainstorms: Application to Macau

Study regionThe study area is the western part of the Macau Peninsula in China, with an area of 4.06 km2. Study focusThis study developed a coupled hydrological-hydraulic model that simulates the two-dimensional (2D) surface flow and one-dimensional (1D) drain pipe flow of compound inundation. The model was applied to Macau, China, as a study area, and the typhoon Mangkhut in 2018 was used as a case study to validate the model’s performance. Simulating compound inundation scenarios of extreme rainfall and astronomical tide and exploring the influence of astronomical tide on coastal urban inundation. New hydrological insights for the regionUrban flood disasters are profoundly influenced by tidal levels, albeit the height of tides alone does not solely exacerbate the phenomenon. Rather, the phase of astronomical tides during rainfall also plays a crucial role in determining the severity of urban flooding. This research has revealed that when rainfall synchronizes with the recession phase of the spring tide, urban flooding conditions become acute, 17.66 % increase in total surface water volume for the scenario with the highest tidal level impact compared to the scenario with the lowest tidal level impact. This paper presents the response of coastal cities to the flooding process under different combined rainstorm-astronomical tide scenarios, to provide scientific guidance for disaster preparedness planning in coastal areas, and to improve the resilience of disasters.

Insight into the production factors influencing the physicochemical properties of densified briquettes comprising wood shavings and rice husk

The present work aims at elucidating the impact of various densification parameters on the physicochemical and combustion properties of fuel briquettes issued from the co-processing of wood shavings (W) and rice husks (RH) using a mechanical piston press machine. To that end, a design of experiments integrating three feeding speeds (15.76, 18.56, and 21.73 mm·s−1), two wood particle sizes (< 7 mm and between 7 and 10 mm) and six different RH contents ranging from 0 to 100 wt% was built. The obtained results showed that all the above operating factors influence the apparent density of the produced briquettes. Values ranging from 1143 to 1247 kg·m−3 were notably measured, with the highest one determined when considering a low feeding speed, small wood particles and an RH proportion of 80 wt%. While increasing the RH content led to an increase in the briquette density, the obtained results also showed that the higher the RH content, the lower the water resistance index. Measured values indeed went from 94 % on average for pure wood to ⁓85 % for pure RH, attesting to the potential challenge associated with the storage of briquettes containing high RH contents. As for the net calorific value, it was shown to rise from ⁓11 to ⁓ 16 MJ·kg−1 when varying the proportion of wood between 0 and 100 wt%. This trend was especially traced to an increase of the wt% of volatile matters in the produced briquettes accompanied by a decrease of their ash content. Combustion tests performed with different briquette samples then allowed inferring burning rates between 10.9 and 13.4 g·min−1, specific fuel consumptions ranging from 115.8 to 138.4 g·l−1 and combustion efficiencies of around 12 %. As highlights, these tests demonstrated that the higher the wood content, the higher the burning rate, the lower the specific fuel consumption and the higher the combustion efficiency. Finally, two tested briquette formulations containing 80 and 100 wt% of wood were shown to have better combustion properties than a commercial firewood used for comparison. Total greenhouse gas (CO2 and CH4) emissions were even found to be reduced by 9.4 % when burning the RH-containing sample instead of firewood, while providing the same amount of sensible heat to a 3-l volume of water. These findings thus highlight the potential interest of beneficiating biomass wastes into briquettes for heat generation, further noting that the development of this type of alternative energy carrier offers multiple advantages in terms of waste management, reduction of the deforestation induced by the intensive use of firewood and mitigation of climate change through a potential reduction greenhouse gas emissions.

Evaluation of volumetric threshold shear strain of gravel-sand mixtures in centrifuge model tests

A series of dynamic centrifuge modeling tests were conducted to evaluate the volumetric threshold shear strain of loose gravel-sand mixtures composed of various ratios of gravel and sand by weight. The maximum and minimum void ratios of the mixtures were evaluated, and the optimum packing condition was determined when the mixture contained approximately 60–70 % gravel by weight. A total of six centrifuge modeling tests were performed at 50-g centrifuge gravitational acceleration. Each centrifuge model was subjected to six shaking events consisting of uniform sinusoidal motions with various amplitudes and numbers of cycles. During the entire duration of the test, the development of excess pore water pressure and settlement was monitored. Empirical relationships of pore water pressure ratio and shear strains were developed for these mixtures. The development of excess pore water pressure in the mixtures with greater than 60 % gravel exhibits transient behavior, while residual excess pore water pressure was observed in the mixtures with less than 60 % gravel. Based on the results, the volumetric threshold strain evaluated from the generation of pore water pressure and volume change during shaking is similar. The values were found to be in a range of 0.03–0.10 % and are influenced by soil composition. The threshold strain increases as the amount of gravel in the soil mixture increases.

Electrical conductivity of forage subjected to different sobbing times and water volumes

Electrical conductivity of forage subjected to different sobbing times and water volumes