Preparation of a Novel Cement from Red Mud and Limestone

Red mud (RM) is an industrial waste obtained from the Bayer process which is usually discharged into marine or disposed into a landfill causing pollution for the surrounding water, air, and soils. Thus, disposal of RM is an environmental concern, and it should be recycled effectively. Because RM consists of iron- and aluminum-rich phases, it is possible to be processed into cementitious material and utilized for construction purposes. This research fabricated a type of cement from the mixture of RM and limestone. The mixture was sintered at temperature of 1180 °C to obtain the clinker of the novel hydraulic cement with C2S, C3A, and C4AF minerals. In which, C2S, C3A, and C4AF are respectively belite, alite, and tetra-calcium aluminoferrite compounds that are characteristic hydraulic minerals of Portland cement clinker. The specifications of this cement were tested and evaluated in this study such as chemical and mineralogical compositions, fineness, specific surface area, mechanical strength after 3, 7, and 28 days.

Physicochemical and biological quality of groundwater sources in Kadama Sub county, Kibuku District

IntroductionWater should comply with standard/regulatory physio-chemical and biological parameters to ensure that it is safe for domestic use. We therefore sought to assess the physico-chemical and biological quality of groundwater sources in Kadama subcounty, Kibuku district, Eastern Uganda. MethodsA cross-sectional quantitative study was conducted. We collected water samples from twenty-three functional water sources. We assessed the turbidity, pH and presence of Escherichia coli (E. coli) using the turbidity meter, pH meter and membrane filtration technique, respectively. Furthermore, physical sanitary inspection of the water sources was done using a standard pretested observational checklist to assess existing risk factors.ResultsThe majority, 69.5% of the water sources included in the study were boreholes, with about 43.5% of them from Nandere parish. Majority of the water sources 86.9% (20/23) had clogged/blocked drainage channels, about a third of water sources 60.9% (14/23) did not have fences/protection around them and majority of the water sources, 82.6% (19/23) had stagnated apron. Some water sources 8.7% (2/23) had open defecation around them. The water samples had a mean pH of 6.87 (SD 0.920) with 4.4% acidic, 86.9% normal/acceptable pH level and 8.6% in alkaline state. About two-thirds (65.3%) of these water sources had turbidity levels less than 5 NTUs. In addition, boreholes had a better turbidity score of 81.2% (13/16) compared to the water wells 71.4% (5/7). About half, 43.5% of the water sources were above the WHO recommended range of zero coliforms. ConclusionsSome ground water sources had sanitary risk factors and significant levels of E. coli which makes them unfit for human consumption, though they can be used for other domestic purposes including washing clothes. This calls for urgent need to keep surrounding water sources clean and continuously disinfect drinking water from groundwater sources before human consumption.

High-resolution screening for marine prokaryotic and eukaryotic taxa with selective preference for PE and PET surfaces

Marine plastic debris serve as substrates for the colonization of a variety of prokaryote and eukaryote organisms. Of particular interest are the microorganisms that have adapted to thrive on plastic as they may contain genes, enzymes or pathways involved in the colonization or metabolism of plastics. We implemented DNA metabarcoding with nanopore MinION sequencing to compare the one-month-old biomes of hydrolysable (polyethylene terephthalate) and non-hydrolysable (polyethylene) plastics surfaces vs. those of glass and the surrounding water in a Mediterranean Sea marina. We sequenced longer 16S rRNA, 18S rRNA and ITS barcode loci for a more comprehensive taxonomic profiling of the bacterial, protist and fungal communities respectively. Long read sequencing enabled high-resolution mapping to genera and species. Using differential abundance screening we identified 32 bacteria and five eukaryotes, that were significantly differentially abundant on PE or PET compared to glass. This approach may be used in the future to characterize the plastisphere communities and to screen for microorganisms with a plastic-metabolism potential.

An Interplay between Viruses and Bacteria Associated with the White Sea Sponges Revealed by Metagenomics

Sponges are remarkable holobionts harboring extremely diverse microbial and viral communities. However, the interactions between the components within holobionts and between a holobiont and environment are largely unknown, especially for polar organisms. To investigate possible interactions within and between sponge-associated communities, we probed the microbiomes and viromes of cold-water sympatric sponges Isodictya palmata (n = 2), Halichondria panicea (n = 3), and Halichondria sitiens (n = 3) by 16S and shotgun metagenomics. We showed that the bacterial and viral communities associated with these White Sea sponges are species-specific and different from the surrounding water. Extensive mining of bacterial antiphage defense systems in the metagenomes revealed a variety of defense mechanisms. The abundance of defense systems was comparable in the metagenomes of the sponges and the surrounding water, thus distinguishing the White Sea sponges from those inhabiting the tropical seas. We developed a network-based approach for the combined analysis of CRISPR-spacers and protospacers. Using this approach, we showed that the virus–host interactions within the sponge-associated community are typically more abundant (three out of four interactions studied) than the inter-community interactions. Additionally, we detected the occurrence of viral exchanges between the communities. Our work provides the first insight into the metagenomics of the three cold-water sponge species from the White Sea and paves the way for a comprehensive analysis of the interactions between microbial communities and associated viruses.

Photo-Degradation of Orange G as an Environmental Pollutant with TiO2-ZnO Composite Material

The increasing water pollution is a great concern as millions of people don't have access to pure water in Bangladesh. A considerable number of people are dying of contaminated water each year not only in Bangladesh but all over the world. Many industries, tanneries, companies, etc. are emitting lots of environmentally hazardous materials into the surrounding water. Many of these pollutants are industrial dyes. The dyes loss from the industrial water during dyeing operation damage the esthetic merit of surface water. They minimize light penetration, hamper aquatic lives and hinder photosynthesis. Some dyes may also have toxic, mutagenic, and carcinogenic characteristics. The purpose of this research is to get rid of the pollutant dye Orange G before the water is contaminated. A method named photo-degradation using different light sources is used to mineralize Orange G dye with composite materials including TiO2-ZnO. This composite was prepared by the hydrothermal method. The photocatalytic behavior of the prepared composite TiO2-ZnO helps in minimizing the effect of this dye to save the water from contamination. The composite compoundwas studied by experimenting on photo-degradation with Orange G under different light sources such as visible light, UV light, and sunlight. The photo-degradation percentage was found to maximum of 79.60 in the presence of sunlight. The percentages of photo-degradation under UV light and visible light were 48.0 and 18.40 respectively.

The Optical Characterization and Distribution of Dissolved Organic Matter in Water Regimes of Qilian Mountains Watershed

The constituents and content of dissolved organic matter (DOM) in the Qilian Mountain watershed were characterized with a spectroscopic technique, especially 3-DEEM fluorescence assisted by parallel factor (PARAFAC) analysis. The level of DOM in the surrounding area of Qinghai lake (thereafter the lake in this article specifically refers to Qinghai Lake)was highest at 9.45 mg C·L−1 and about 3 times less (3.09 mg C·L−1) in a cropland aquatic regime (the lowest value). In general, DOM was freshly autochthonously generated by plankton and plant debris, microorganisms and diagenetic effects in the aquatic environment (FI > 1.8). Component 1 (humic acid-like) and 3 (fulvic acid-like) determined the humification degree of chromophoric dissolved organic matter (CDOM). The spatial variation of sulfate and nitrate in the surrounding water regime of the lake revealed that organic molecules were mainly influenced by bacterial mediation. Mineral disintegration was an important and necessary process for fluorescent fraction formation in the cropland water regime. Exceptionally, organic moiety in the unused land area was affected by anespecially aridclimate in addition to microbial metabolic experience. Salinity became the critical factor determining the distribution of DOM, and the total normalized fluorescent intensity and CDOM level were lower in low-salinity circumstances (0.2–0.5 g·L−1) with 32.06 QSU and 1.38 m−1 in the grassland area, and higher salinity (0.6~0.8 g·L−1) resulted in abnormally high fluorescence of 150.62 QSU and absorption of 7.83 m−1 in the cropland water regime. Climatic conditions and microbial reactivity controlled by salinity were found to induce the above results. Our findings demonstrated that autochthonous inputs regulated DOM dynamics in the Qilian Mountains watershed of high altitude.

Physicochemical and biological quality of groundwater sources in Kadama Sub county, Kibuku District

IntroductionWater should comply with standard/regulatory physio-chemical and biological parameters to ensure that it is safe for domestic use. We therefore sought to assess the physico-chemical and biological quality of groundwater sources in Kadama subcounty, Kibuku district, Eastern Uganda.MethodsA cross-sectional quantitative study was conducted. We collected water samples from twenty-three functional water sources. We assessed the turbidity, pH and presence of Escherichia coli (E. coli) using the turbidity meter, pH meter and membrane filtration technique, respectively. Furthermore, physical sanitary inspection of the water sources was done using a standard pretested observational checklist to assess existing risk factors.ResultsThe majority, 69.5% of the water sources included in the study were boreholes, with about 43.5% of them from Nandere parish. Majority of the water sources 86.9% (20/23) had clogged/blocked drainage channels, about a third of water sources 60.9% (14/23) did not have fences/protection around them and majority of the water sources, 82.6% (19/23) had stagnated apron. Some water sources 8.7% (2/23) had open defecation around them. The water samples had a mean pH of 6.87 (SD 0.920) with 4.4% acidic, 86.9% normal/acceptable pH level and 8.6% in alkaline state. About two-thirds (65.3%) of these water sources had turbidity levels less than 5 NTUs. In addition, boreholes had a better turbidity score of 81.2% (13/16) compared to the water wells 71.4% (5/7). About half, 43.5% of the water sources were above the WHO recommended range of zero coliforms.ConclusionsSome ground water sources had sanitary risk factors and significant levels of E. coli which makes them unfit for human consumption, though they can be used for other domestic purposes including washing clothes. This calls for urgent need to keep surrounding water sources clean and continuously disinfect drinking water from groundwater sources before human consumption.

Recent Progresses in Stable Isotope Analysis of Cellulose Extracted from Tree Rings

In this work, the challenges and progression in stable isotope investigation, from the analytical tools and technical sample preparation procedures to the dendroclimatological experiments, were reviewed in terms of their use to assess tree physiological responses to environmental changes. Since the isotope signature of whole wood is not always a reliable tool in studying the climate changes, cellulose is often preferred as the study material in paleoclimatic studies. Nevertheless, the isotope analysis of cellulose is challenging due to the difficulty to remove the other wood components (extractives, lignin, pectin, and hemicelluloses). Additionally, in the case of hydrogen isotope analysis, about 30% of the hydrogen atoms of cellulose are exchanged with the surrounding water, which complicates the isotope analysis. In recent years, more automated isotope analysis methods were developed based on high temperature pyrolysis of cellulose, followed by the chromatographic separation of H2 from CO and by their individual isotope analysis using isotope ratio mass spectrometry. When used to investigate climate factors, the combined isotope analysis δ13C and δ18O appears to be the most promising isotope tool. In contrast, the role of δ2H values is yet to be elucidated, together with the development of new methods for hydrogen isotope analysis.

A simplified fluid structure interaction model for the assessment of ship hard grounding

The structural damage of ships in navigational accidents is influenced by the hydrodynamic properties of surrounding water. Fluid structure interactions (FSI) in way of grounding contact can be idealized by combining commercial FEA tools and specialized hydrodynamic solvers. Despite the efficacy of these simulations, the source codes idealizing FSI are not openly available, computationally expensive and subject to limitations in terms of physical assumptions. This paper presents a unified FSI model for the assessment of ship crashworthiness following ship hard grounding. The method uses spring elements for the idealization of hydrostatic restoring forces in 3 DoF (heave, pitch, roll) and distributes the added masses in 6 DoF on the nodal points in way of contact. Comparison of results against the method of Kim et al. (2021) for the case of a barge and a Ro–Ro passenger ship demonstrate excellent idealization of ship dynamics. It is concluded that the method could be useful for rapid assessment of ship grounding scenarios and associated regulatory developments.

Distinct Seasonal Primary Production Patterns in the Sub-Polar Gyre and Surrounding Seas

Primary production (PP) in the sub-polar region appears to be important for ocean carbon uptake but how the different water masses contribute to the PP occurring here has not yet been described. Using two models based on satellite observations of surface chlorophyll, light and temperature, seasonal patterns in the distribution of PP are shown here to differ in the sub-polar gyre south of the Greenland-Scotland Ridge (GSR) and surrounding water masses. Monthly averages of PP (2003–2013) were determined. Total and seasonal PP were similar in both models. Average PP in five of the domains (0.47–0.77 g C m–2 d–1) was well above the global average (0.37 g C m–2 d–1). Over the East Greenland shelf, however, total annual PP was estimated to be only 0.19 g C m–2 d–1. The Norwegian shelf was the most productive of the regions studied. “Spring blooms” appear sporadically as spikes in the annual distribution of PP in some regions/years, but do not emerge as a dominant feature in the average annual development of PP in any of the domains. For all regions, ∼25% of the annual PP takes place in the period January-May. PP peaked over most of the study area at or around maximum insolation or temperature. PP in the study region as a whole appears to be more related to latitude or water masses than to bathymetry. In waters over the East Greenland shelf, the Norwegian shelf, and north of the GSR up to 50% of annual PP had taken place when ∼50% of the annual flux of light has reached the surface. In contrast, only about 35% of annual PP had taken place in the sub-polar gyre and waters over the southern open shelf by this time. Light-use efficiency differences may be explained by differences in mixed layer depth (MLD). Multi-model Earth System model studies have indicated that climate change may decrease the MLD in the sub-polar gyre and suggest this may lead to a decrease in the PP occurring here. The results presented here, however, suggest that a shallower MLD could lead to an increase in PP.