Coal Waste Research Articles

DAYA TAMPUNG SETTLING POND TERHADAP BEBAN PENCEMARAN TOTAL SUSPENDED SOLID DARI LIMBAH BATUBARA PT. JORONG BARUTAMA GRESTON

The impact of the mining process including the emergence of Total Suspended Solids (TSS), either directly or indirectly can disrupt the life of aquatic biota, damage environmental sustainability, and threaten the welfare of humans who depend on the water for various daily purposes. To reduce the burden of pollution on water bodies due to coal mining waste, one of the technologies often chosen is the Wastewater Management Plant (WWTP) system, which generally involves the use of settling ponds. This study aims to analyze the total suspended solids in the settling pond, analyze the total suspended solid capacity, and compile recommendations for total suspended solid management efforts to meet environmental quality standards. The total suspended solids (TSS) values in October and November measurements at the inlet were 339.00 mg/l and 712.00 mg/l while the outlet decreased to 42.50 mg/l and 55.00 mg/l. The total suspended solid (TSS) value during the measurement period of January – December 2023 shows that the TSS value at the inlet and outlet for 12 months shows a value below the quality standard. The first settling pond with a capacity of 15,000 m, and the second to sixth settling ponds have a capacity of 3,000 m3 each. To maintain the capacity of the settling pond at around 60% of its maximum capacity, the volume of TSS deposited ranges from 9,000 m3, while in the second to sixth settling ponds, the volume of TSS deposited each ranges from 1,800 m3.

Co-gasification of Jordanian olive mill solid waste and RTC coal for thermochemical treatment: characterization and equilibrium modelling

Co-gasification of Jordanian olive mill solid waste and RTC coal for thermochemical treatment: characterization and equilibrium modelling

Application of Chemically Modified Coal Mine Waste for the Sustainable Management of Fluoride in Drinking Water

Application of Chemically Modified Coal Mine Waste for the Sustainable Management of Fluoride in Drinking Water

Identifikasi Potensi Penambahan Limbah Batu Bara sebagai Penyedia Hara Pertumbuhan Tanaman Cabai

Fly ash as coal burning waste contains a variety of main compounds such as CaO, SiO2, Al2O3, Fe2O3, MgO, MnO, Na2O, K2O and some heavy metals. The composition of each compound is different depending on the combustion condition parameters in the industry. Rice husk waste reaches 20-30% of the grain produced and has not been utilized optimally by farmers. Therefore, the use of a mixture of fly ash and husk requires further study as an innovative soil improvement product. The aim of this research is to identify the use of fly ash and rice husks as environmentally friendly soil amendments or fertilizers. Fly ash is mixed with organic components such as burnt husks, goat manure with different compositions. The product obtained is then placed in the soil of the chili plants using the method of spreading 0.5 g on 1.5 kg of soil. Tests were carried out both on the soil regarding the value of the degree of acidity and humidity and the growth of chili plants as indicators of the effect of adding fly ash on their growth. The results of fly ash waste can be used as a soil conditioner with a range of acidity between 6.5 to 8.5 fly ash with a nitrogen content of 0.49%, 0.18% phosphorus, 0.6% potassium with a carbon value of 6.9% and C/N ratio 14.08. These conditions are good for the soil for chili plants. The increase in height increases on days 1 to 9, while leaf width tends to remain constant on days 3 to 9. The results of this research contributes on the developing the use of fly ash in agriculture so that the absorption of fly ash waste can be done on a large scale.

Trace Elements Distribution in the k7 Seam of the Karaganda Coal Basin, Kazakhstan

We investigated the distribution patterns and evaluated the average contents of trace elements in the k7 seam of the Karaganda coal basin in Central Kazakhstan. This paper presents the results of studying the geochemistry of 34 elements in 85 samples of the k7 seam. The study employed a suite of advanced high-resolution analytical methods, including atomic emission spectrometry with inductively coupled plasma (ICP–OES) and mass spectrometry with inductively coupled plasma (ICP–MS), along with their processing and interpretation. It was determined that the concentrations of trace elements in the k7 seam are primarily associated with lithophile elements, revealing high concentrations of Li, V, Sc, Zr, Hf, and Ba. Additionally, increased concentrations of Nb, Ta, Se, Te, Ag, and Th were observed compared to the coal Clarke. Specific Nb(Ta)–Zr(Hf)–Li mineralization accompanied by a group of associated metals (Ba, V, Sc, etc.) was identified. The study revealed lateral and vertical heterogeneity of the rare elements’ distributions in coals, attributed to the formation dynamics of the coal basin. A correlation between Li and Al2O3 with a less positive relationship with K2O suggests the affinity of certain elements (Li, Ta, Nb, and Ba) to kaolinite. Clay layers showed increased radioactivity, with Th—13.2 ppm and U—2.6 ppm, indicating the possible presence of volcanogenic pyroclastic rocks characterized by radioactivity. Taken together, these data reveal the features of the rock composition of the source area, which is considered a mineralization source. According to geochemical data, it was found that the source area mainly consists of igneous felsic rocks, indicating that the formation occurred under conditions of a volcanic arc. This study’s novelty lies in estimating the average trace elements in the k7 seam, with elevated concentrations of certain elements that suggest promising prospects for industrial extraction from coals and coal wastes. These findings offer insights into considering coal as a potential source of raw material for rare metal production, guiding the industrial processing of key elements within coal. The potential extraction of metals from coal deposits, including from dumps, holds significance for industrial and commercial technologies, as processing critical coal elements can reduce disposal costs and mitigate their environmental impact.

Assessment of the surface water quality and primary health risk in urban wastewater and its receiving river Kathajodi, Cuttack of eastern India.

Kathajodi, the principal southern distributary of the Mahanadi River, is the vital source of irrigation and domestic water use for densely populated Cuttack city which receives anthropogenic wastes abundantly. This study assesses the contamination level and primary health status of urban wastewater, and its receiving river Kathajodi based on the physicochemical quality indices employing inductively coupled plasma mass spectroscopy and aligning with guidelines from the United States Environmental Protection Agency (USEPA) and WHO. The high WQI, HPI, and HEI in the catchment area (KJ2, KJ3, and KJ4) indicate poor water quality due to the influx of domestic waste through the primary drainage system and effluents of healthcare units. A high BOD (4.33-19.66mg L-1) in the catchment indicates high organic matter, animal waste, bacteriological contamination, and low DO, resulting in deterioration of water quality. CR values beyond limits (1.00E - 06 to 1.00E - 04) in three locations of catchment due to higher Cd, Pb, and As indicate significant carcinogenic risk, while high Mn, Cu, and Al content is responsible for several non-carcinogenic ailments and arsenic-induced physiological disorders. The elevated heavy metals Cd, Cu, Fe, Mn, Ni, and Zn, in Kathajodi, could be due to heavy coal combustion, vehicle exhaust, and industrial waste. On the other hand, Cu, Fe, K, and Al could be from agricultural practices, weathered rocks, and crustal materials. Positive significant (p ≤ 0.05) Pearson correlations between physicochemical parameters indicate their common anthropogenic origin and similar chemical characteristics. A strong correlation of PCA between elements and physiological parameters indicates their role in water quality deterioration. Assessing the surface water quality and heavy metal contents from this study will offer critical data to policymakers for monitoring and managing public health concerns.

Preparation and Properties of Expansive Backfill Material Based on Municipal Solid Waste Incineration Fly Ash and Coal Gangue

To realize the large-scale utilization of municipal solid waste incineration (MSWI) fly ash in the field of building materials and to reduce the cost of coal mine backfill mining, the effects of the mixing ratio of cementitious materials, the particle size distribution of aggregates, and the amount and mass concentration of cementitious materials on the properties of backfill materials were experimentally investigated, and the microstructure of the hydration products was analyzed. The results showed that as the mass ratio of MSWI fly ash to bottom ash increased, the rate of expansion of the cementitious system continued to increase, and the compressive strength of the cementitious system continued to decrease. The Al (aluminum) and AlN (aluminum nitride) in the fly ash reacted with water to generate gas, causing the expansion of the cementitious materials; NaOH increased the alkalinity of the solution, which promoted the formation of more bubbles, thereby improving the expansion performance of the cementitious material. When the content of NaOH was 0.9%, the sample rate of expansion could reach 15.9%. The addition of CaCl2 promoted the early hydration reaction of the cementitious material, forming a dense microstructure, thus improving the early strength and rate of expansion of the cementitious material. The compressive strength of the backfill body increased as the fractal dimension of the aggregate particles increased, and the particle grading scheme of group S1 was optimal. The 1-day, 3-day, and 28-day strengths of the backfill body of group S1 reached 0.72 MPa, 1.43 MPa, and 3.26 MPa, respectively. It is recommended to choose a backfill paste concentration ranging between 78.5% and 80% and a reasonable amount of cementitious material between 20% and 25%. After the MSWI fly ash was prepared as a backfill material, the leaching of potentially harmful elements in the fly ash was greatly reduced, and the concentration of dioxin was reduced to 13 ng TEQ/kg. This was attributed to the dilution of the cement, the physical encapsulation of gel products, and the isomorphous replacement of Ca2+ in calcium aluminate chloride hydrate.

Study on Preparation of Calcium-Based Modified Coal Gangue and Its Adsorption Dye Characteristics.

Efficient and thorough treatment of dye wastewater is essential to achieve ecological harmony. In this study, a new type of calcium-based modified coal gangue (Ca-CG) was prepared by using solid waste coal gangue as raw material and a CaCl2 modifier, which was used for the removal of malachite green, methylene blue, crystal violet, methyl violet and other dyes in water. When the dosage of Ca-CG was 1-5 g/L, the dosage of Ca-CG was the main factor affecting the dye adsorption effect. The adsorption effects of Ca-CG on four dyes were as follows: malachite green > crystal violet > methylene blue > methyl violet. Kinetics, isotherms and thermodynamic analysis showed that the adsorption of malachite green, methyl blue, crystal violet and methyl violet by Ca-CG fitted the second-order kinetic model, and adsorption with chemical reaction is the main process. The adsorption of four dyes by Ca-CG conformed to the Freundlich model, which is dominated by multi-molecular layer adsorption, and the adsorption was easy to carry out. The adsorption process of Ca-CG on the four dyes was spontaneous. The results of FTIR, XRD and SEM showed that the calcium-based materials such as lipscombite and dolomite were the key to the adsorption of malachite green by Ca-CG, and the main mechanisms for the adsorption of malachite green by Ca-CG are surface precipitation, electrostatic action, and chelation reaction. Ca-CG adsorption has great potential for the removal of dye wastewater.

PEMANFAATAN FLY ASH DAN BOTTOM ASH PLTU REMBANG UNTUK PEMBUATAN BETON MENGGUNAKAN SEMEN PPC

The research aims to reduce the amount of coal burning waste of fly ash and bottom ash PLTU Rembang as a substitution of cement and sand in the production of quality concrete K-225 and waterproof using Portland Pozzolan cement. The method was experimented in the laboratory by making 50 samples of 15 x 15 x 15 cm3 test objects for 28 days, 60 days, and water absorption tests. The test objecte was made in 5 variations: normal concrete (without substitution) and 20% bottom ash substitution concrete and fly ash mixture 0%, 5%, 10%, 15%. Strong K-225 pressure occurs at the age of 60 days on bottom ash substituted concrete 20% with fly ash 0%, 5% 10% and 15% respectively of 245 kg/cm2, 254,67 kg/cm2, 250,67 kg/cm2, dan 250,67 kg/cm2. Water absorption of concrete at 28 days of ashes substitution was less than 20% and ashes flew below 0% and 5%, 10% 15% resulted in 4.85%, 5.17%, 5.05%, and 5.18%. The results of the research showed that the concrete made meets the K-225 quality and better absorption than normal concrete.

Rare earth element enrichment in coal and coal-adjacent strata of the Uinta Region, Utah and Colorado

This study aims to quantify rare earth element enrichment within coal and coal-adjacent strata in the Uinta Region of central Utah and western Colorado. Rare earth elements are a subset of critical minerals as defined by the U.S. Geological Survey. These elements are used for a wide variety of applications, including renewable energy technology in the transition toward carbon-neutral energy. While rare earth element enrichment has been associated with Appalachian coals, there has been a more limited evaluation of western U.S. coals. Here, samples from six active mines, four idle/historical mines, four mine waste piles, and seven stratigraphically complete cores within the Uinta Region were geochemically evaluated using portable X-ray fluorescence (n = 3,113) and inductively coupled plasma-mass spectrometry (n = 145) elemental analytical methods. Results suggest that 24%–45% of stratigraphically coal-adjacent carbonaceous shale and siltstone units show rare earth element enrichment (>200 ppm), as do 100% of sampled igneous material. A small subset (5%–8%) of coal samples display rare earth element enrichment, specifically in cases containing volcanic ash. This study proposes two multi-step depositional and diagenetic models to explain the enrichment process, requiring the emplacement and mobilization of rare earth element source material due to hydrothermal and other external influences. Historical geochemical evaluations of Uinta Region coal and coal-adjacent data are sparse, emphasizing the statistical significance of this research. These results support the utilization of active mines and coal processing waste piles for the future of domestic rare earth element extraction, offering economic and environmental solutions to pressing global demands.

Hydropedological Characterization of a Coal Mining Waste Deposition Area Affected by Self-Burning

Coal mining often produces severe environmental effects, including impacts on the soil system and, specifically, on hydropedological conditions that control the leaching of significant ions and Potentially Toxic Elements (PTEs). The research objective is to assess changes in the hydropedological conditions in an area with a coal mining waste pile that underwent self-burning. An integrative approach was implemented, starting with the definition of hydropedological zoning based on field observations of soil formation factors (namely, parent material, relief, biological activity, anthropic influence, and time). The soil profile in each hydropedological zone was characterized regarding morphological features. The upper mineral horizons were sampled and characterized in terms of mineralogy and PTE geochemistry. Field measurements of unsaturated hydraulic conductivity, soil water content, and hydrophobicity were performed. Afterwards, the hydrogeochemistry of leachates was determined, and the soil leaching potential was evaluated. The research outcomes express substantial differences regarding the hydropedological zones: development of different soil profiles, diverse mineralogy and PTE geochemistry, higher unsaturated hydraulic conductivity and leaching of major ions, and PTEs in soils affected by coal mining activities. Finally, a Principal Component Analysis confirmed the existence of significant contrasts according to hydropedological zoning.

Preparation of porosity-adjustable porous adsorbent materials derived from coal solid waste

Coal solid waste (CSW) was explored as precursor to prepare porous adsorption material (ACSW) by carbon dioxide activation. The effects of activation method (direct activation and pre-carbonization followed by activation), activation temperature, and activation time were systematically investigated. The burn-off characteristics of the CSW were measured, the ACSW were characterized by field emission scanning electron microscope, gas adsorption instrument and Raman spectrometer, and, in parallel, the adsorption ability was studied using methylene blue (MB) as a typical pollutant. The results showed that compared with direct activation, pre-carbonization reduced the carbon loss, increased the pore volume with pore size less than 1 nm, improved the carbon structural order and increased the MB adsorption performance. In addition, the evolution of the structure of the ACSW strongly depended on the activation temperature and time. With the increase of the activation time, the pore structure evolution underwent three stages: pore forming, expanding, and collapsing. Pore forming mainly involved clearing scattered graphite structures and amorphous carbon. Pore expanding mainly relies on consumption of regular graphite carbon crystal structure. At low temperature of 800 °C, micropores fully developed. As the activation temperature increased to 850–900 °C, pore expansion became apparent, mainly forming pores of 1–5 nm. Moreover, the MB adsorption capacity was positively correlated with the pore volume with pore size less than 5 nm. The burn-off can serve as an indicator for evaluating pore structure and the adsorption performance and when it was ∼25.5 %, the ACSW had the largest pore volume with pore size less than 5 nm and the highest MB adsorption capacity.

Impact of fine lightweight aggregates and coal waste on structural lightweight concrete: Experimental study and gene expression programming

Light Expanded Clay Aggregate (LECA) is one of the materials used to make lightweight concrete. In this study, two types of lightweight aggregates including LECA in both coarse and fine aggregate forms and pumice in fine aggregate form have been used to produce lightweight aggregate concrete. Coal waste is also used as partial replacement for cement. The results show that the usage of pumice as partial replacement for sand and LECA as coarse aggregate is applicable and can used for producing structural lightweight aggregate concrete. Furthermore, by using and increasing in the amount of LECA as fine aggregate, the slump of lightweight concrete in comparison to using sand, is also increased. The mixtures with LECA in both fine and coarse aggregate forms have the best results. Also, the results show that adding the coal waste improves the properties of lightweight concrete, and the optimal ratio is about 15% as partial replacement for cement by weight. In addition, gene expression programming is employed to establish empirical connections derived from experimental outcomes. In this regard, a relationship is proposed to determine the compressive strength of lightweight aggregate concrete based on the experimental data. The outcomes of gene expression programming demonstrate that the suggested formula exhibits good accuracy and efficiency in forecasting the specified parameter.

POLITICAL SHIFT LAW SETTLEMENT OF FLY ASH AND BOTTOM ASH (FABA) COAL BASED ON ECOLOGICAL JUSTICE

Purpose: This research aims to gain a comprehension understading on the factors causing the shift in political law regulation of fly ash and bottom ash (FABA) coal waste from hazardous and toxic waste (B3) to non-B3 status and provide a solution to the regulatory model for coal FABA based on ecological justice. Theoretical framework: This study also anchors from environmental justice theories known as “political ecology” from the perspective of “procedural justice” and “distributive justice”. Method: This qualitative research was approached as socio-legal research specifications. Miles et al.’s (2014) qualitative data analysis process was employed to analyze the data. Result and conclusion: The research results show that the political shift in the legal regulation of FABA should be based on ecological justice. The causal factor, the formation of law, is influenced by political and economic factors. While economic factors remain the dominant basis in establishing Government Regulation Number 22 of 2021, the environment should also be the consideration. Most of the construction of the regulation has not been based on the precautionary principle, non-regression, ecological justice, Pancasila justice, certainty, benefit, legal morality, and international agreements. Practical implication: This study contributes that the implementation of environmental protection and management needs to be reconstructed based on provisions, principles, and principles in forming arrangements such as the precautionary principle, the precautionary principle, the non-regression principle, the ecological justice principle, national justice [Pancasila], certainty, expediency, legal morality, and international agreements, to produce regulations in the environmental sector based on ecological justice.

WEAR RESISTANT OF CACO3/FLY-ASH CERAMIC MATRIX COMPOSITE

This study aimed to investigate the potential of utilising fly ash, a harmful byproduct of coal waste, in the manufacturing of composite materials to reduce its environmental impact. Calcium carbonate (CaCO3) and fly ash were mixed with zinc stearate using the powder metallurgy method to create wear-resistant samples. The compaction load was adjusted to achieve optimal low-pressure compaction, with pressures of 22.75 MPa, 23.45 MPa, 24.14 MPa, and 24.83 MPa used for single punch pressing. After 10 minutes of holding time, sintering was conducted at 900 OC for 1 hour. The raw materials were tested using X-ray diffraction (XRD) and sieved based on the mesh size. The composite was characterised through various tests, including density testing, wear testing, and scanning electron microscopy (SEM) to observe the microstructure. The density value increased with the compaction load, with a maximum apparent density of 1.794 g/cm3 and the highest porosity percentage at a pressure of 22.75 Mpa of 31.155%. Furthermore, the specific wear value decreased as the compaction load increased, with the lowest specific abrasion value of 1.17 x 10-6 mm2/kg. Therefore, using fly ash to produce composite materials is a promising solution to reduce the negative impact of coal waste while producing wear-resistant materials.

Assessment of mobile mercury concentration in soils of an abandoned coalfield waste pile in Douro region: the Fojo waste pile (Portugal) study case

PurposePejão Mining Complex locates in Castelo de Paiva municipality and, until its closure in 1994, was one of the most important coal mines in the Douro Coalfield. This work aims to study the presence, quantify, and evaluate the dissemination of mercury (Hg), a potentially toxic element (PTE) of major public health concern by the World Health Organization (WHO), from a waste pile affected by coal fires.Materials and methodsSamples from areas affected and unaffected by the combustion and from surrounding soil were collected from Fojo waste pile region. First, the Hg pseudo-total concentration was estimated for all collected samples by soil microwave–assisted digestion with aqua regia (USEPA 3051A). Then, a sequential extraction procedure (SEP), the USEPA 3200, was applied for Hg fractionation and speciation aiming to evaluate Hg mobility and bioavailability to surrounding ecosystems.Results and discussionThe results obtained showed a Hg enrichment in soil samples when compared to Portuguese and international reference values for soils. Relatively to the Hg availability and mobility, although it predominates in the semi-mobile fraction, the waste pile materials exposed to combustion showed a concerning increase of Hg levels in the mobile fraction that contains the more labile Hg species, being a major source of environmental contamination by Hg.ConclusionsThis study allowed to conclude that combustion of mining residues increased Hg mobility, toxicity, and bioavailability, increasing the contamination potential of the coal waste pile. The methodology applied in this work can be replicated in other abandoned mines to monitor, control, and/or mitigate the Hg environmental impact in the surrounding soils and waters.

Potensi Limbah Fly Ash PLTU Anggrek, Gorontalo Utara sebagai Bahan Substitusi Semen Pada Beton

Accumulation of coal ash waste (fly ash) is a dangerous toxic material (B3) which light and fine so it easily flies in the air. This problem is urgent to be resolved because the production continues to increase in quantity and can cause air and water pollution. Currently, coal waste is used to make bricks, but research needs to be done on its potential as a concrete mixture and even as a cement substitute. Currently, coal waste is used to make bricks, but research necessery on its potential as a concrete mixture and even as a cement substitute. Therefore this research can be an alternative solution to the coal ash waste problem in Gorontalo Province. Research on the use of coal ash as a concrete mixture using crushed stone aggregate and sand from the quarry PT. CMP, Bonda Raya, South Suwawa To obtain a granular distribution that meets the requirements, the proportions used for crushed stone measuring 1-2 cm and measuring 2-3 cm are 65% and 35% respectively. Meanwhile, to obtain a combined gradation of fine and coarse aggregate that meets the requirements, percentages of 55% and 45% are used respectively. Based on the research results, the normal compressive strength value of concrete is 28.827 MPa. The compressive strength of fly ash variations of 5%, 10%, 15%, and 20% is 25,069 MPa, 27,442 MPa, 23,096 MPa, and 20,934 MPa. The compressive strength of fly ash variations is lower than normal concrete. The optimum compressive strength value for fly ash substitution for cement with a 10% variation is 27.442 MPa.

WITHDRAWN: The evaluation model for factors affecting soil quality in waste dumps open-pit coal waste dumps based on fuzzy mathematics

Taking the Hequ open-pit coal mine waste dump as the research object, using the fuzzy analytic hierarchy process and expert scoring theory, 4 criteria and 25 factors were established, including the evaluation model of soil structure stability, soil water retention capacity, soil fertilizer retention capacity, soil biological activity, and factors affecting soil quality in the waste dumps. Using YAAHP calculation software, the weights of various influencing factors on the soil fertility restoration ability of the waste dumps were determined. Combining a fuzzy comprehensive evaluation method to determine soil nutrient standards, soil quality evaluation is divided into 5 levels, and the main influencing factors of soil restoration ability in open-pit coal mine waste disposal sites are quantitatively analyzed. The results showed that: The weight of soil fertility in the criterion layer of the evaluation model was the largest (0.548), followed by soil water retention capacity (0.198), soil biological activity (0.140), and soil structural stability (0.114). The weight of organic matter F1 in the factor layer was the highest (0.116). Due to the final evaluation score of the soil recovery ability of the target layer open-pit coal mine waste dumps is 53.584, the soil quality and nutrients of the waste dumps are in the middle level. The main factors of soil resilience are soil fertility and soil organic matter content, to provide management strategies for improving soil quality of dump, accelerating soil reconstruction, and promoting soil ecosystem restoration.

Mechanical Properties Geopolymer Concrete Based on Fly Ash PLTU Tanjung Jati B Jepara As An Alternative Material

Geopolymer concrete is a new material and has very good prospects because it does not use cement, where the material uses environmentally friendly materials and is energy-efficient, because it can use industrial waste materials and manufacturing processes. Geopolymer concrete does not require too much energy, as does the process from making cement which requires at least temperatures up for 800°C. The aim of this study is to evaluate and examine the worth of geopolymer concrete’s mechanical qualities. Compression tests, split tests, and flexural strength tests on geopolymer concrete are all part of the battery of mechanical properties tests. The trial study of geopolymer concrete was used to inform the mix design employed in the production of the test specimens. Merapi sand fine aggregate, 10-20 mm coarse aggregate, PLTU Tanjung Jati B Jepara fly ash from coal waste, Na2SiO3, 8M NaOH activator, and 2% fly ash superplasticizer were employed in this research. Three 15/30 cylinders are used to test concrete’s compressive strength, three 15/30 cylinders are used to test concrete’s split tensile strength, and three 15x15x60 are used to test concrete’s flexural strength in this study. After only 28 days, testing could begin. Compressive strength was found to be 31.746 MPa, split tensile strength was 3.920 MPa, and flexural strength was found to be 4.833 MPa for geopolymer concrete.

BOLD: Color from Test Tube to Textile

Abstract Red can be the color of passion and danger, or luck and prosperity. Blue can be the shade of sadness—singing the blues—or a sign of tranquility and serenity. As the Russian painter Wassily Kandinsky once affirmed, in his 1911 treatise Concerning the Spiritual in Art , “Color is a power which directly influences the soul.” Color is also culture: we’ve colored our environments, clothes, and bodies for thousands of years, since early humans applied simple organic stains derived from the plants around them. The art and science of dyeing is an ancient one; today it’s an economic and commercial powerhouse. The arrival of the first synthetic dyes in the 1850s—discovered by happenstance from experiments with coal tar waste—brought us a rainbow of new possibilities for fashion and textiles, from color “fads” and trends to new means for self-expression. But synthetic color’s dark side lingers in polluted waterways. A new exhibit at the museum of the Science History Institute explores these complex legacies. Bold: Color From Test Tube To Textile takes visitors on a colorful 150-year journey through the history of synthetic dyes, examining the people and places who’ve shaped our modern understanding of color—from the laboratory to the factory floor, from the runway to retail, and beyond.