Статті в журналах з теми "Lime and Stone dust"
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1
Peter, M. A. "Effects of Stone Dust on Lime Stabilized Granular Soil." IOP Conference Series: Earth and Environmental Science 1110, no. 1 (February 1, 2023): 012024. http://dx.doi.org/10.1088/1755-1315/1110/1/012024.
Повний текст джерелаАнотація:
Abstract This Paper investigated Materials by adding percentage of Stone Dust on the 10% Lime treated soil and observe the improvement of Geotechnical properties. This method expected to improve the Performance of Flexible Pavement by treating the Sub-base Materials locally available in the Construction corridor. The objective of this paper was to evaluate the effects of granular materials by varying the percentage of Stone Dust 5%, 10%, 15%, 20%, 25% and 30% on the 10% Lime treated soil. California Bearing Ratio (CBR) and Unconfined Compressive Strength (UCS) was analysed as the measure of Performance of Flexible Pavement. Investigation showed that as the increase in Lime CBR values increased to 22.4% at 10% Lime compared to 4.7% at 0% but after addition of Stone Dust CBR observed to be improved from 22.4% to 47.1% at 30% Stone Dust which is equivalent to 47.6%. Either as the increase in Lime content the UCS has shown an improvement by 24% where at 2% UCS value was 0.8Mpa and at 10% UCS value was 3.3Mpa after seven days curing and submerged into water for four hours as per standards, as the addition of Stone Dust on the 10% Lime treated Soil UCS values has been increases slightly from 3.3Mpa to 4.76Mpa at 30% Stone Dust + 10% Lime. As the study jointly analysed the associated factors for the Performance of Flexible Pavements which were CBR and UCS, therefore it was established the optimum 10% Lime + 30% Stone Dust content of and established.
2
Nazmunnahar, Mst, and Alena Vimmrova. "Lightweight Gypsum-Based Material, Foamed by Lime Dust and Acid Agent." Applied Mechanics and Materials 729 (January 2015): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amm.729.3.
Повний текст джерелаАнотація:
Lightweight gypsum materials foamed by the help of stone dust were investigated. Lightweight material prepared from the gypsum as a main binder and foamed by stone dust and acid agent. The materials with the bulk density are 607 kg/m3, compressive strength about 1.3 MPa and thermal conductivity was prepared. Basic physical, mechanical and thermal properties were investigated.
3
Rathor, Ajay Pratap Singh, Harshil Bhatt, and Ravi kant Pareek. "Evaluation of Engineering Behaviour of Expansive Soil with Addition of Lime and Quarry Dust." ECS Transactions 107, no. 1 (April 24, 2022): 4747–58. http://dx.doi.org/10.1149/10701.4747ecst.
Повний текст джерелаАнотація:
The Kota city, which is situated in Rajasthan state of India, is having a major problem of disposing the quarry dust. Quarry dust is a waste product produced by the stone industry during the cutting and crushing of stone. This byproduct is affecting the environment and land fertility as well. One of the innovative techniques for ground improvement can be practiced by using quarry dust as soil stabilizing agent. This technique may simultaneously offer the environmental sustainability, use of industrial waste, and space saving. The Expansive Soil (ES) deposits in Kota district and its neighboring districts, Jhalawar and Baran, make it difficult to build large constructions. In order to make the soil suitable for construction, quarry dust and lime are used for stabilization of the ES in this study. The UCS and CBR value was increased after adding of quarry dust with 6% lime and stabilized soil has superior load bearing capacity.
4
Zhukov, E. I., O. V. Pilyaeva, N. V. Golovnykh, and I. I. Shepelev. "Reduction of Fine Dust Emissions During Sintering of Nepheline-Lime-Stone Charge." Ecology and Industry of Russia 27, no. 8 (August 1, 2023): 16–21. http://dx.doi.org/10.18412/1816-0395-2023-8-16-21.
Повний текст джерелаАнотація:
It was found that dust of electrostatic precipitators supplied to the sintering furnace from the hot end precipitates little on the sintered material of the raw charge of alumina production of JSC "RUSAL Achinsk", increases the dust turnover and dust release of solid pollutants from the furnace into the atmosphere. In order to increase efficiency of purification of atmospheric air from fine dust of electric precipitators it is proposed to remove it from dust circulation of the sintering furnace and dispose of it separately in technology of road mixture when laying the base of road pavements. The introduction of this technology provides a reduction in atmospheric emissions from 18.965 to 5.859 g/s, a reduction in coal consumption by 1.39 kg of conventional fuel for the production of 1 ton of sinter and savings of coal fuel by 8350 tons per year.
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Neham, Sahar S. "IMPROVING RUTTING RESISTANCE OF HOT MIX ASPHALT BY DATES KERNEL POWDER." IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING 18, no. 2 (August 4, 2018): 296–310. http://dx.doi.org/10.32852/iqjfmme.vol18.iss2.94.
Повний текст джерелаАнотація:
In Iraq, the significant increase in the number of passenger cars and trucks (increased inaxle loads) in addition to the unprecedented rise of temperature in the summer hasincreased the risk of permanent deformation of flexible pavement (Rutting) in recenttimes. Lower costs maintenance and extending serves life of flexible pavements are themain objectives of this study by improving rut resisting of it using the waste locallyavailable materials (Dates Kernel Powder).The Superpave design criteria is used to determine optimum asphalt content at 4% airvoids for hot mix with Lime Stone Dust and Dates Kernel Powder as a filler materials tothree types of aggregate blend. Preparing 54 samples with dimension (400*300*50) mmat 110˚C compacted temperature to test it by Wheel-Tracking device at 40˚C, 50˚C and60˚C. Based on wheel-tracking device results, it can be show that there was a significantdecrease in the value of the Rut Depth when using the Dates Kernel Powder as analternative to Lime Stone Dust as a filler materials in Hot Mix Asphalt and it can be usedto improve the rut resisting; the maximum percent of reduction is 67.71 after 3000 cycleof passing at 60ºC and 49.35 as a minimum percent of reduction after 5000 cycle at 40ºCtested temperature, then it can be seen that the impact of Hot Mix Asphalt with DatesKernel Powder is less at high temperatures than mixes with Lime Stone Dust on RutDepth value.
6
Nitish, S. S. S., De Sangita, A. V. S. L. Ramya, and G. Sudheer Kumar. "Comparative Study on Soil Stabilization using Industrial by Products and Coconut Coir." Journal of Physics: Conference Series 2040, no. 1 (October 1, 2021): 012014. http://dx.doi.org/10.1088/1742-6596/2040/1/012014.
Повний текст джерелаАнотація:
Abstract Waste disposal has become a serious concern in developing countries like India. The substitution of these waste materials in the form of stabilizing agents in soil stabilization is a modern approach by which waste materials can be advantageously used. In many instances, the soil has proven to be problematic for the construction of various infrastructures like embankments, pavements, foundations, hydraulic barriers, etc. In the present study, a particular type of soil is stabilized to improve the physical properties by using multiple admixtures. In general, additives such as lime, cement, sawdust, stone dust, and other compounds are used for the stabilization of soil over years. This study is conducted to evaluate the viability of using Coconut Coir Fibre (CC) along with stone dust (SD)/pond ash (PA) as a stabilization material. A comparative analysis on the effect of CC with SD as well CC with PA on engineering characteristics of silty soil is presented in the present study. A sequence of laboratory experiments was conducted on silty soil blended with Coconut Coir Fibre along with proportions of Stone Dust/Pond Ash from 0.5% to 1.5% and 30% as constant respectively by mass of dehydrated soil. The experimental outcomes shown a significant change in properties of soil, which conclude that the coconut coir along with stone dust as a very potential additive to improve the characteristics of silty soil compared to that of pond ash.
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Samal, Rasmiranjan, and Ayan Mishra. "Effect of Stone dust and Lime in the Geotechnical Properties of Clayey Soil." IOP Conference Series: Materials Science and Engineering 970 (November 17, 2020): 012028. http://dx.doi.org/10.1088/1757-899x/970/1/012028.
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Vaghela, B. N. "A Review Paper on Performance of SCC Containing Lime Stone Powder and Quarry Dust." International Journal for Research in Applied Science and Engineering Technology V, no. II (February 28, 2017): 607–9. http://dx.doi.org/10.22214/ijraset.2017.2090.
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Htun, Zaw Z., Yi Y. Win, Aung M. Myat, and Soe M. Naing. "Lung Function Impairment and Workplace Control Measures among Marble Stone Carvers in Sa-Kyin Village, Madayar Township, Myanmar." International Journal of Occupational Safety and Health 11, no. 1 (April 3, 2021): 25–30. http://dx.doi.org/10.3126/ijosh.v11i1.34972.
Повний текст джерелаАнотація:
Introduction: Marble rocks, composed of dust containing calcium carbonate and silica particles, predispose to a higher prevalence of occupational lung diseases. This study aimed to assess workplace control measures and lung function impairment among marble stone carvers.
Methods: A cross-sectional descriptive study was conducted among 120 marble stone carvers in Sa-Kyin Village, Madayar Township in May 2019. Information about existing control measures in the workplace was assessed using a pre-tested structured questionnaire and participants’ lung function using spirometry. Respirable dust measurements in twelve randomly selected workers were performed by personal air sampling pumps.
Results: It was found that 9.2% of marble stone carvers used disposable or cloth masks throughout the working time, but no one was found using appropriate devices like respirators. No one reported about regular medical checkup and provision of health education at the workplaces. Spirometry testing showed 55.8% had lung function impairment. Concentrations of respirable dust ranged from 7.19 to 10.13 mg/m3, significantly higher than the recommended Threshold Limit Value (3 mg/m3). In multivariable logistic regression analysis, development of lung function impairment was associated with age [adjusted Odds Ratio (aOR) = 2.84; 95% CI = 1.02,7.91] and use of face mask (aOR = 0.11; 95% CI = 0.01,0.91).
Conclusion: The working environment was found dusty, and a significant proportion of workers had lung function impairment. It is essential to adopt proper dust control measures in stone carving workplaces. Preventive measures like medical surveillance and health education program are vital to reduce the burdens from occupational lung diseases.
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Syed, Afzal Basha, Reddy B. Jayarami, and C. Sashidhar. "Significance of utilizing stone dust and kadapa marble powder in high strength concrete." i-manager’s Journal on Civil Engineering 12, no. 1 (2022): 1. http://dx.doi.org/10.26634/jce.12.1.18528.
Повний текст джерелаАнотація:
In the current research work, an attempt has been made to study the properties of high strength concrete using the blend of stone dust and Kadapa Marble Powder (KMP). In M60 grade mix of concrete, fine aggregates are partially supplanted with stone buildup and KMP is being added as a mineral admixture. Manufactured sand and stone dust are being used as fine aggregates in the experimentation. Mechanical properties like compression, split tension and flexural strength have been performed and contrasted with the referral concrete. The aim of the research is to study the impact of replacing natural sand with manufactured sand and stone powder and substitution of cement with KMP on the mechanical properties of high strength concrete. The test results showed clear improvement in the mechanical properties of concrete by using manufactured sand, stone dust and KMP together in M60 bend. The increment in the magnitude of strengths is comparable with conventional concrete. By using stone dust and KMP, additionally, one gets the green benefit of utilizing a characteristic material instead of engineered ones.
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Ghaffari, Alireza, and Amirreza Ghaffari. "The Effect of Fly Ash on Lime Mortar on Elevated Temperature." Advanced Materials Research 684 (April 2013): 172–76. http://dx.doi.org/10.4028/www.scientific.net/amr.684.172.
Повний текст джерелаАнотація:
To enhance the mechanical and compressive strength of lime mortar(lime-sand ) the fly ash was added to the compound to improved the engineering performance of lime mixture .The addition of fly ash and lime stone dust to clay soils reduce their plasticity characteristics, swell potential and improve their compressive strength (Brooks et al. 2011) .Boardman et al (2001) observed that no significant pozzolonic activity appears to take place until 7 days of curing during their experiments at room temperature .In this research the effect of fly ash at different range from 30 to 70 percent of mix by varying lime percentage from 6 to 20 percent with thermodynamic parameters of their reaction was assessed in normal and raised temperature by curing compacted specimens in the laboratory .The compressive strength of fly ash and lime mixture are determined on curing period up to 28 days in normal state and one days on raised one .The Result portrayed that raised temperature highly boosted the compressive strength of the mix from 30 to 120 percent at different range of fly ash mixture with lime.
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Ilić, Miloš, Sandra Milutinović, Branislav Rajković, and Daniela Urošević. "Selection of a dedusting system for the lime stone preparation plant in the deposit "Zagradje-5"." Mining and Metallurgy Engineering Bor, no. 3-4 (2020): 57–66. http://dx.doi.org/10.5937/mmeb2004057i.
Повний текст джерелаАнотація:
This paper presents an example of a dedusting system in the deposit "Zagradje-5" with the use of two different dedusting systems in order to more efficiently removal of harmful dust from the plant. The analysis is done by calculation and is a universal method of calculating the dedusting system, the results of which are necessary to verify the reliable operation of selected equipment. The technical characteristics of the filter and deduster as well as the technological scheme of dedusting are also given.
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Deshmukh, Anand, Nikhil Pradip, Sarang Dhatrak, and Subroto Nandi. "Assessment of Occupational Dust and Silica Exposure in Indian Stone Mining and Crushing Unit- A Case Study." Current World Environment 12, no. 3 (December 25, 2017): 661–69. http://dx.doi.org/10.12944/cwe.12.3.17.
Повний текст джерелаАнотація:
Stone crushing industry plays a vital role in the economy and urban development of fast developing countries like India. Stone mines and crushers in India are located around major cities and roughly employ around 5,00,000 peoples throughout the country. However this employment generating industry also happens to be one of the most dust generating activity and also a precursor to the respiratory disease, silicosis. This study was undertaken with an objective to estimate the personal exposure of the workers to silica laden dust in this industry sector. Personal dust sampling (n=11) and (n=6) was carried out in stone crushing and stone mining (quarry)areas respectively over a period of three consecutive days in selected units in a suburban area of Nalgonda district of Telangana state in India. The respirable dust exposure and free silica content was then estimated. It was observed that three (3) samples of crusher helper from the Crushing Unit had exposures exceeding the Permissible Limit Value (PLV) of Indian Factories Act1948. Two (2) Heavy Earth Moving Machineries (HEMM) operators from stone mining area were observed to have exceeded the Permissible Maximum Exposure Limit (PMEL) prescribed by the Indian Mines Act 1952 and subsequent rules their under. The remaining samples of HEMM operators from mining area and of the crusher helper from the crusher plant were observed to be within the prescribed limits of respective guidelines prescribed by the Indian statutory agencies. Two different acts were considered, because of the fact that stone mining is regulated by the Indian mining act and under the overall control of Directorate of Mines and Safety (DGMS), Government of India. On the other hand Crusher plant comes under the ambit of Model Factory Rule 120 under section 87 of Indian Factories Act 1948 under the overall control of Directorate General Factory Service and Labour Institute (DGFASLI) Government of India. Post the study it could be concluded that, stone crushers are dustier as compared to stone mining area. Workers in stone mining and crushing units of study area are indeed exposed to high levels of respirable and silica laden dust. It was observed that safety and precautionary measures towards dust and silica exposure are not implemented necessitating to be taken by unit operators.
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G, Chidananda. "Mechanical and Durability Characteristics of Eco-Friendly Fly Ash Bricks." International Journal for Research in Applied Science and Engineering Technology 9, no. 11 (November 30, 2021): 1381–85. http://dx.doi.org/10.22214/ijraset.2021.39034.
Повний текст джерелаАнотація:
Abstract: This paper presents an experimental investigation carried out on eco-friendly fly ash bricks having various percentage of fly ash, lime, gypsum, stone dust, coarse aggregate and boiler slag. Raw materials are added to the pan mixer with different mix proportions and are mixed thoroughly with water until a homogeneous mixture is formed. Prepared homogeneous mixture is fed into the press and moulded to a brick of size 200 x 200 x 300 mm using vibro-hydraulic press. Moulded bricks are air dried for 24 hours, arranged in stacks and are cured for a period of 28 days by sprinkling the water to achieve the optimum strength. Compressive strength, water absorption, efflorescence, dimension tolerance and density tests are conducted as per BIS codal provisions. Eco friendly fly ash bricks having varying proportions of industrial by-products with less content of stone dust satisfy compressive, water absorption, efflorescence, dimensional tolerance and density requirements as per BIS codal provisions and can be used in structures as a sustainable construction material. Keywords: Eco-friendly fly ash bricks, Compressive strength, Water absorption, Efflorescence, Dimension tolerance and Density
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Naidu T Y, Rohith, and G. V. V. Satyanarayana. "Study on aerated concrete using steam curing test method." E3S Web of Conferences 309 (2021): 01206. http://dx.doi.org/10.1051/e3sconf/202130901206.
Повний текст джерелаАнотація:
The Accumulation of warm and moisture in building walls plays an vital role in its upkeep and power conservation. Aerated Concrete block, an environmental material gives an anticipated result to building construction. Aerated Concrete can build light weight, eco-friendly, non-structural wall, reduced dead weight concrete blocks. Aerated Concrete is developed introducing aluminium powder which reacts with the calcium hydroxide on hydration of cement. Several curing test methods are done to find out the optimum dosage of aluminium content. The Aerated concrete blocks are pre-casted by mixing Portland cement, fly ash, GGBS, quarry dust, lime stone powder, water and aluminium powder.
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Khaliullin, M. I., R. Z. Rakhimov, and A. R. Gaifullin. "Composition and structure of the stone composite gypsumbinder with additives of lime and the ground haydite dust." Vestnik MGSU, no. 12 (December 2013): 109–17. http://dx.doi.org/10.22227/1997-0935.2013.12.109-117.
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Paul, Bikram, and Kushal Ghosh. "Effects of Higher Percentage of Stone Dust Used as a Fine Aggregate in Concrete and Variation of Strength due to the Variation of Cement Content and W/C Ratio." Asian Journal of Engineering and Applied Technology 7, no. 2 (November 5, 2018): 1–6. http://dx.doi.org/10.51983/ajeat-2018.7.2.1013.
Повний текст джерелаАнотація:
Abstract – Sustainability and Unavailability play an important role while we choose material for manufacturing of concrete. Nowadays, both Central and State Govt. have taken legal action on the extraction of sand from the river bed due to the bad impacts on the river like changes the shape, slope of the bed and also in the channel morphology. Due to the implementation of this type of law, legal sand quarries did not able to make balance with the rapid growth of the construction industry. That’s why, to make profit and supply extra needs of sand to the concrete industry “Sand Mafias” involved into the illegal trades of the sand. To counteract these sorts of socio-economic problems, we have to go for an alternative fine aggregate. Though it may not be possible to replace fully, we have to concentrate on the sand being replaced by the high percentage of alternative fine aggregate. Stone dust is a by-product from rock crusher and it can be recycled by using it in the concrete and maintained the sustainability. As stone dust has acceptable properties of fine aggregate sand with regard to shape and texture, it can be thought of as an alternate fine aggregate but research is needed on the extent of sand replacement by stone dust. The present study is done keeping in mind the use of stone dust as high as possible. That’s why two Design Mix have been designed M20 and M25. For M20 grade of concrete sand has been replaced by stone dust 25%, 30% and 35% by volume and the basic strength properties of concrete have been investigated for the above replacements like compressive strength, flexural strength, split tensile strength etc. In case of M25 grade of concrete 30%, 40% and 50% replacement of sand have been done and variation cement content and water-cement ratio has been done by comparing the target mean strength of M25 grade of concrete.
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Gokulapadu, Azmathulla, Vinod Kumar T, and Afzal Basha Syed. "Effects of using Stone Dust and GGBS in Concrete." International Journal of Engineering Technology and Management Sciences 4, no. 5 (September 28, 2020): 88–92. http://dx.doi.org/10.46647/ijetms.2020.v04i05.016.
Повний текст джерелаАнотація:
Concrete being most utilized development material comprises of solidifying material, fine aggregate, coarse aggregate and required amount of water. Due to rapid growth of infrastructure development activities, the available sources of natural material like sand are getting exhausted at very fast rate. The only way is to search alternative materials. In place of sand, materials like stone dust can be used which possess similar properties like sand. Cement with ground granulated impact heater slag (GGBS) substitution has risen as a significant option in contrast to regular concrete and has quickly drawn the solid business consideration because of its concrete investment funds, vitality reserve funds, and cost reserve funds, natural and financial advantages. In the current test examination an exertion is made to measure the quality of GGBS and stone residue at different substitution levels and assess its efficiencies concerning concrete. The results have demonstrated the positive outcomes with respect to the mechanical properties of concrete.
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Koppisch, Dorothea, Mario Arnone, and Stefan Gabriel. "28 Evaluation of Work-Related Exposures to the Inhalable and Respirable Dust Fraction and to Respirable Quartz." Annals of Work Exposures and Health 67, Supplement_1 (May 1, 2023): i5. http://dx.doi.org/10.1093/annweh/wxac087.013.
Повний текст джерелаАнотація:
Abstract Dust is found in the entire environment as well as in working areas. When assessing dust exposure at workplaces, measurements on inhalable and respirable dust are performed. Furthermore, quartz is used as an agent or is released in the form of respirable dust in a number of work processes. Between 2005 and 2016, 35,000 measurements on each dust fraction were performed in the “Measurement System for Exposure Assessment” – MGU. In addition, 15,000 measurements on respirable quartz were performed in this data period. These exposure data on the dust fractions and quartz was stored in the IFA exposure-database MEGA. Statistic evaluations of these data were done according to industrial sectors and work areas. Further grouping criteria like the measurement strategy ("personal measurements" and "stationary sampling") and the sampling time (≥ 2 hours and < 2 hours) help to describe the dust and quartz exposure at work places. Dust and quartz exposures occurring in working areas were analysed for about 20 different industrial sector groups like ceramic and glass industry, foundries, or metalworking and mechanical engineering. These sector groups were further divided in individual sectors and typical tasks performed in these sectors. For example, the tasks stone cutting in stone masonry, mixing and filling in the chemical industry or powder coating in the metalworking sector. The statistical evaluations from the MEGA database are published in IFA-reports about the exposure to inhalable and respirable dust and to quartz for prevention and for retrospective considerations.
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Marichamy, V., S. Ganesan, and R. Kalirajan. "Influence of Stone Crusher Units’ Dust Pollution on Agriculture in Virudhunagar District of Tamil Nadu." Shanlax International Journal of Economics 8, no. 2 (March 1, 2020): 41–48. http://dx.doi.org/10.34293/economics.v8i2.2070.
Повний текст джерелаАнотація:
In this process, many industries are polluting the air and environment. One among them is the stone crushing industry. Air polluting industries are a proximate source of major damage to farming systems in adjacent areas, thus disrupting the main source of livelihoods of many small and marginal farmers. Scientific study shows that polluted air from industrial and urban areas usually consists of a mixture of pollutants, which can adversely affect agriculture in many complex ways. Air pollutants that are most damaging to agriculture are sulphur dioxide and the oxides of nitrogen, which are categorized as acid pollutants. Agriculture yields depend upon many factors like weather, soil fertility, irrigation, pesticides, and the like. Other things remaining the same, air pollution, particularly dust pollution, causes a significant fall in crop yields, and in turn, agriculture income reduces. Hence a modest attempt has been made here to study the influence of dust pollution by stone crushing units in the surrounding areas of Virudhunagar District. The results of the Factor Analysis show that the spread of dust from stone crushing units has affected the fertility of the soil, led to a reduction in the area of cultivation, and has a negative impact on cattle breathing and ultimatelyaffected the income levels of the farming community.
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Awed, Ahmed M., Abdallah E. Aboelela, Ahmed S. El-Ashwah, Mofida Allam, and Sherif M. El-Badawy. "Improvement of unbound granular pavement layers and subgrade with cement dust in Egypt." International Journal of Pavement Research and Technology 13, no. 6 (November 2020): 621–29. http://dx.doi.org/10.1007/s42947-020-6010-9.
Повний текст джерелаАнотація:
AbstractThe main goal of this study is to assess the technical viability of using cement dust as part of the fines percentage in the unbound granular base/subbase pavement layers’ and subgrade soil as a viable sustainable solution. This study investigates the effect of adding cement dust to five types of pavement road materials which are collected from different ongoing roadway construction projects (1) Reclaimed Asphalt Pavement (RAP), (2) crushed stone base aggregates, (3) blend of crushed stone base aggregates with RAP, (4) crushed stone subbase aggregates, and (5) sandy subgrade soil. The resilient modulus (Mr) is selected as the main characteristic for evaluating the investigated materials’ stiffness. The regression parameters (k1, k2, and k3) of the universal Mr prediction model are found by fitting the experimental results of Mr testing for two replicates per each material type. The results show that using 3–5% of cement dust improves the estimated Mr of the investigated base/subbase materials and subgrades at the anticipated field stresses by 8–21%., As a result the structural layer coefficients are enhanced by 11–17%. KENLAYER nonlinear damage analysis confirms that using 3–5% of cement dust improves the predicted rutting life by up to 12% and the fatigue life up to 27%. Based on a typical pavement structure, enhancing pavement base/subbase layers and subgrade soils with 3–5% of cement dust reduces asphalt layer thickness from 11.25 to 12.50% and increases base/subbase layer thickness from 8.75 to 12.50% to maintain the same predicted rutting and fatigue lives of the typical structure. This positively affects the total construction cost in addition to the ecological benefits.
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Bartoszek, Sławomir, Grzegorz Ćwikła, Gabriel Kost, and Krzysztof Nieśpiałowski. "Impact of the Selected Disturbing Factors on Accuracy of the Distance Measurement with the Use of Ultrasonic Transducers in a Hard Coal Mine." Energies 15, no. 1 (December 24, 2021): 133. http://dx.doi.org/10.3390/en15010133.
Повний текст джерелаАнотація:
The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of measurements with the use of different transducers (AR30 and AR41), which were selected and pre-tested in previous research projects, was realized. The impact of such disturbing factors as airborne dust (coal, stone, lime and mixed dust), changes in temperature and humidity on the propagation of ultrasonic waves, amplitude and measurement accuracy was investigated. The tests were preceded by theoretical analysis. It was found that the transducers selected for the tests had a sufficient accuracy and range, so they can be used in the devices planned to be designed, allowing for the determining of the location of a roadheader in hard coal mine roadways, taking into account technical and legal restrictions. It was also specified which disturbing factors should be compensated and what methods and parameters of this compensation should be used.
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Aleksandrova, A. Yu, and S. S. Timofeeva. "Dust-Fraction of Granites, Migmatites, Marbleized Limestones, Ophiocalcites as a Carrier of Nanosized Dust Particles." Bulletin of Irkutsk State University. Series Earth Sciences 36 (2021): 3–15. http://dx.doi.org/10.26516/2073-3402.2021.36.3.
Повний текст джерелаАнотація:
In this work, we will discuss the study the dispersed composition stone dust such industrial objects as deposits migmatites, granites, marbleized limestone and ophiocalcites. The dust-like fraction the listed rocks is considered and evaluated as a micro-sized and nanosized component their structure formation. The main regularities of the formation nano- and microdust particles have been determined by the method membrane filtration. The most promising feature membrane filtration for the separation of professional (stone) dust mining quarries has been developed, which must be taken into account when developing a technology for processing raw materials, when separating particles into fractions for further use in the production the final product, when standardizing and qualitatively assessing the effect a nanosized fraction on the human body and environment. As a result the experiments carried out, the dispersed composition the rocks extracted at the quarries raw materials in the Irkutsk region was analyzed. The percentage particles with dimensions from 0.05 to 10 microns in the studied samples of professional dust was determined. The presence nanosized particles in them was confirmed, which, in turn, are the carrier a negative component, which can be considered from the point view industrial safety and health protection miners as a factor in the development such occupational diseases.
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Amin, Muhammad Nasir, Kaffayatullah Khan, Muhammad Umair Saleem, Nauman Khurram, and Muhammad Umar Khan Niazi. "Aging and Curing Temperature Effects on Compressive Strength of Mortar Containing Lime Stone Quarry Dust and Industrial Granite Sludge." Materials 10, no. 6 (June 11, 2017): 642. http://dx.doi.org/10.3390/ma10060642.
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Tanushree Mahapatra. "Environmental, social and health impacts of stone quarrying in Mitrapur panchayat of Balasore district, Odisha." International Journal of Science and Research Archive 8, no. 1 (February 28, 2023): 678–88. http://dx.doi.org/10.30574/ijsra.2023.8.1.0142.
Повний текст джерелаАнотація:
Excessive demand for stones due to rapid infrastructure development led to uncontrolled stone quarrying in Mitrapur panchayat of Balasore district causing serious environmental degradation and socio-economic conflict. A large numbers of tribal people of this area are dependent on stone quarrying activities for carrying their livelihood. Methodology include field observation, photo documentation and interview of local people through a predesigned structured questionnaire to know the local people perception about the impacts of quarrying. This current study was conducted through collection of data from local people of five villages namely, Chatrikhunta, Chandipur, Patana, Kathagochhi and Jamudiha of Mitrapur panchayat of Balasore. Majority tribal people of study area (53%) depends upon quarrying activity for their livelihood. Many local people complained about various negative effects of stone quarrying activities. A vast majority of respondent stated that they suffered severely from the noise pollution caused from the stone quarry related activities (83%). Major source of noise pollution were stone crushers (54%), transport of material by truck/dumper/ tractor (24%) and use of dynamite in blasting operation in quarry (22%). About 40% respondent complained about the impact of dust pollution on agriculture. The availability of water resources in the study area varied from site to site. Many health impacts like bodily pain, eye infection, sleepless nights, headache, cough and chest pain have been reported due to engagement in stone quarrying. In spite of its contribution towards development, quarrying is also responsible for several negative environmental and socio-economic impacts, particularly when quarrying activity is carried out haphazardly.
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Kim, Jiyoung, Chan Hee Lee, Ran Hee Kim, and Eun Jeong Shin. "Characterization of White and Black Deposits on the Surface of Korean Stone Cultural Heritages." Microscopy and Microanalysis 19, S5 (August 2013): 167–71. http://dx.doi.org/10.1017/s1431927613012580.
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AbstractWhite and black deposits have been frequently observed on the surface of Korean stone cultural heritages, and they are considered as damage factors in both conservation and esthetic points of view. In order to set up the appropriate conservation remedy, it is important to know their origins, characteristics, and compositions. In this study, optical and scanning electron microscopes (SEMs) equipped with an energy-dispersive spectrometer (EDS) and X-ray diffractometer were employed to determine the white and black deposits. It was found that both deposits consisted mainly of calcium carbonate (calcite) and calcium sulfate (gypsum). The calcite and gypsum were characterized by bladed, rhombohedral, tabular, and amorphous morphologies under a SEM. The black deposit was not only composed of calcite or gypsum, but also accompanied amorphous and irregular matrix. SEM-EDS analysis revealed an abundance of silicon, aluminum, iron, phosphorus, and carbon on the matrix, which were major elements of soil, atmospheric deposits, and organisms. The white deposit, on the other hand, barely contained those coloring substances. These salts and deposited substances were caused by chemical reaction and physical adhesion between rock-forming minerals, lime mortar, sulfur in polluted air environment, soil dust, and microorganisms.
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Amadi E., Nkama. "Glassphalt Concrete Production Using Stone Dust as a Filler through Trial Mix Design." International Journal of Advanced Research in Engineering 3, no. 4 (December 29, 2017): 1. http://dx.doi.org/10.24178/ijare.2017.3.4.01.
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Various studies have shown that waste glass has been crushed and screen and can serve as an alternative replacement of fines and coarse aggregate when mixed with Bitumen to form a glassphalt concrete which can be used in landscaping or non-load bearing walls in a building. This researched work was intended to compare and analyze the hot mix glassphalt (HMG) and the strength of asphalt concrete using trial mix design through investigative of their performances. The mineral fillers with different percentage by total weight of the mixture used in the study were crushed igneous rock that passes from 0.075mm to 200mm sieve sizes. However, this production did not only establish the usage of glassphalt but also analysis grade of bitumen like 60/70, 30/40, 80/100, 180/200 etc, its sustainability for various road uses either for priming eg. MCI, tackcoat eg. RSI, or surface dressing e.g S125. Various tests were conducted like water absorption test, marshal stability test, void ration test etc. using bitumen grade 60/70 which has a flash point of 250oc and a melting point of 48 – 56oc. Different types of glassphalt concrete was classified: Macadam, Binder course and wearing course with experimental design to determining the maximum deformation load that will deform the glassphalt concrete to aid in predicting its design life span and equally makes necessary recommendations.
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Choudhary, Rajan, Dibyatonu Chattopadhyay, Abhinay Kumar, and Ashok Julaganti. "Use of industrial wastes as filler in open-graded friction courses." Baltic Journal of Road and Bridge Engineering 12, no. 2 (June 27, 2017): 106–16. http://dx.doi.org/10.3846/bjrbe.2017.13.
Повний текст джерелаАнотація:
For a fast developing economy like India, expansion, rehabilitation, and maintenance of transportation infrastructure is crucial and require huge quantities of high quality natural aggregates. Meanwhile, vast amounts of industrial wastes accumulating in the country pose problems related to safe and sustainable disposal. The present study investigated possible utilisation of marble dust, a waste from stone industry, and fly ash, a waste from thermal power stations, as filler materials in open-graded friction course mixes. Open-graded friction course mixes incorporating fly ash, marble dust, and two sources of stone dust as filler fractions were designed and evaluated for mix design properties including draindown, abrasion loss, air void content, and permeability. Morphology of each filler was characterised through scanning electron microscopy. Physicochemical properties of fillers were examined through Rigden voids, German filler test, methylene blue, and hydrometer analysis. Analysis of variance using Fisher multiple comparison procedure was performed to evaluate the effect of filler type on design properties of open-graded friction course mixes. Regression analysis using forward selection technique was performed to identify significant filler characteristics influencing open-graded friction course properties. Results showed that filler type affected open-graded friction course design parameters significantly. Open-graded friction course mixes with marble dust showed promising performance with lowest draindown, and highest durability, air voids, and permeability. Regression analysis identified Rigden void content of filler materials as a major filler characteristic affecting the mix design parameters of open-graded friction course mixes.
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Supar, K., F. A. A. Rani, N. L. Mazlan, and M. K. Musa. "Partial Replacement of Fine Aggregate Using Waste Materials in Concrete as Roof Tile: A Review." IOP Conference Series: Materials Science and Engineering 1200, no. 1 (November 1, 2021): 012008. http://dx.doi.org/10.1088/1757-899x/1200/1/012008.
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Abstract The use of waste material as a partial replacement has become popular in concrete mixture studies. Many research has utilized waste materials like cement, fine aggregate, coarse aggregate, and reinforcing materials substitute. The current paper focuses on some of the waste elements that are utilized in a concrete mortar (use in roof tile) as a partial replacement for fine aggregates such as rubber ash, sawdust, seashells, crumb rubber, pistachio shells, cinder sand, stone dust, and copper slag. There are many variations of mix proportion and water-cement ratio for every waste material. Compressive strength was compared and found that stone dust and the combination of seashell and coconut fiber shows an incensement when used to replacing fine aggregate. The suitable replacement level for stone dust is 25% and 50%. While the suitable replacement levels for the combination of sea shell and coconut fiber are 20% and 30%. Material from the rubber families such as rubber crumb and rubber ash is only suitable for replacement levels. Rubber families especially rubber crumbs have shown low water absorption value which is good in the production of roofing products. As we know, the roof should have waterproof properties to prevent any leaks from happening when it rains. Most of the waste materials added as fine aggregates in concrete have increased the amount of water absorption and found that sawdust is the most abundant material with a high percentage of water absorption compared to the others. Research on the partial replacement of fine aggregates replaced with waste materials is needed more extensively to provide more confidence about their use in concrete mortars, especially on roof tiles.
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Fayissa, Basha, Oluma Gudina, and Biruk Yigezu. "Application of Sawdust Ash as Filler Material in Asphaltic Concrete Production." Civil and Environmental Engineering 16, no. 2 (December 1, 2020): 351–59. http://dx.doi.org/10.2478/cee-2020-0035.
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AbstractAn increase production of wastes from different companies and agricultural areas creates severe surrounding trouble in terms of management and removal in Ethiopia. Utilization of by-products and residue in construction work is an excellent alternative solution in reducing disposal problems. In this research, the application of sawdust ash in asphalt concrete production is investigated as filler material. Physical and chemical tests were investigated for Saw Dust Ash (SDA). Asphalt specimen prepared using basaltic stone dust without sawdust as filler used as a control material. The SDA was partially replaced with 3 %, 6 %, 9 %, and 12 % by amount of basaltic dust. Performance evaluation of combinations was explored with fatigue, tensile strength, and deformation resistances experiment. The outcome pointed that the use of SDA as packing material enhanced the fatigue life and permanent deformation of asphalt concrete with variable temperature. Furthermore, it was identified that the combination with SDA indicated less sensitive to moisture than basaltic dust. Research finding indicated, an optimum value of SDA could be replaced the basaltic dust is 12 % in asphaltic concrete production.
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Kurpaska, Sławomir, Katarzyna Wolny-Koładka, Mateusz Malinowski, Klaudia Tomaszek, and Hubert Latała. "Thermal-Mass and Microbiological Analysis of Forced Air Flow through the Stone Heat Accumulator Bed." Energies 16, no. 11 (May 31, 2023): 4456. http://dx.doi.org/10.3390/en16114456.
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Heat storage in systems integrated with renewable energy sources in facilities can reduce the consumption of fossil fuels, cut maintenance costs, and decrease greenhouse gas emissions from buildings and other objects. One of the possible solutions is the use of a stone heat accumulator for short-term heat storage and the use of this deposit in the ventilation process of the facility. During short-term air flow through the porous material from which an accumulator bed is made, there is an exchange of heat and mass between the flowing air and the bed particles. In the long term, the use of an accumulator can lead to an increase in dust and the development of pathogenic microorganisms, endangering human life and health. Therefore, understanding the factors influencing the efficient use of a stone deposit is very important. The aim of this study is to calculate the changes in thermal-mass parameters in the air flowing out of the stone accumulator and to assess the effect of long-term stone accumulator use on the content of microorganisms and dust concentration in bioaerosol. The application of the heat storage system in the stone bed leads to the formation of strictly controlled microclimatic conditions, and the tested air does not constitute a threat to the people staying in the object. The concentration standards of PM10 and PM2.5 exceeded the limit values (PM2.5 = 20 μg∙m−3 and PM10 = 40 μg∙m−3), and, thus, the air in the studied greenhouse was classified as polluted. The analysis also showed that, for the analyzed conditions, a 20% increase in the initial temperature of the accumulator bed results in a nearly 20% increase in the outlet air temperature.
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Brodny, Jarosław, and Magdalena Tutak. "Exposure to Harmful Dusts on Fully Powered Longwall Coal Mines in Poland." International Journal of Environmental Research and Public Health 15, no. 9 (August 27, 2018): 1846. http://dx.doi.org/10.3390/ijerph15091846.
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The mining production process is exposed to a series of different hazards. One of them is the accumulation of dust which can pose a serious threat to the life and health of mine workers. The analysis of dust hazard in hard coal mining should include two aspects. One is the risk of coal dust explosions, which poses a direct risk of injury or even loss of life, the second is the risk of harmful dust, associated with the possibility of negative health effects as a result of long-term exposure to dust in the worker’s body. The technologies currently applied in underground mining produce large amounts of coal and stone dust. Long-term exposure to dust and crystalline silica may cause chronic respiratory disease. The article presents the results of tests on the dust levels in the area of a fully-powered longwall. The tests were conducted for five longwalls from different hard coal mines. In each of them, the average values of inhalable and respirable dust as well as the percentage content of free silica in the dust were determined in ten selected working positions. Additionally, for the longwall with the highest dust concentration, the levels of dust were determined for the basic activities related to the phases of the technological cycle. The comparative analysis conducted and the results obtained demonstrate large variations in the dust levels in the different areas. The permissible values were significantly exceeded in a number of cases. This poses a great threat to the health of Polish miners. The results obtained indicate that it is necessary to undertake more effective measures in order to improve the working environment of the crew in hard coal mines.
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Acchar, Wilson, Joao B. Duarte, and Vamberto Monteiro Silva. "Study of the Substitution of Natural Fine Aggregates by Stone Dust in the Concrete of the Portland Cement." Materials Science Forum 881 (November 2016): 331–35. http://dx.doi.org/10.4028/www.scientific.net/msf.881.331.
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The concept of sustainable construction throughout the building life cycle has motivated several studies on the application of waste to replace partially or totally some materials such as aggregates. This study evaluated the feasibility of stone dust use, replacing the natural sand in the production of structural concrete. In the initial stage it was carried out physical and chemical characterization of the applied materials and then molded cylindrical specimens with FCK 20, 25 and 30 MPa at 28 days, in compositions at levels of 10% stone powder, 30%, 50%, 100% e 100% with additive. After curing they were subjected to compressive strength tests and mechanical tests showed that the composition with 10% presented promising results.
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Ramesh, H. N., and C. Rakesh. "Influence of Lime Sludge and Sodium Salts on the Strength and Structural Behavior of Clayey Soils–Granite Stone Slurry Dust Composite with Curing." Indian Geotechnical Journal 50, no. 5 (January 2, 2020): 801–9. http://dx.doi.org/10.1007/s40098-019-00404-3.
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Iman, Syed Ali, and Sourabh Lalotra. "To Investigate the Behavior of Concrete by Partial Replacement of Stone Dust with Fine Aggregates and Tobacco Waste Ash with Cement." International Journal for Research in Applied Science and Engineering Technology 10, no. 9 (September 30, 2022): 854–61. http://dx.doi.org/10.22214/ijraset.2022.46746.
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Abstract: Concrete is considered to be as a composite material consisting of cement, fine aggregate, and coarse aggregate, and demand for concrete is increasing day by day due to large scale constructions. The industrial waste contains many inorganic and toxic substances far away the acceptable limit which cause an impact on the environment. Scarcity of the const. materials used the natural resources like sand aggregates and stone aggregate. The partial replacement of aggregates is need for the future generation of concrete structures for the environment supportable. The depletion of the natural resources gets exhausted. Certain materials of mineral origin are also added to concrete to enhance their strength and durability properties of concrete materials such as Stone Dust and other by TWA.
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Muehlbauer, Mikael. "From Stone to Dust: The Life of the Kufic-Inscribed Frieze of Wuqro Cherqos in Tigray, Ethiopia." Muqarnas Online 38, no. 1 (December 6, 2021): 1–34. http://dx.doi.org/10.1163/22118993-00381p02.
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Abstract Until 2010 (when it was broken by a tourist), a curious Kufic-inscribed sandstone block greeted those who entered the narthex of the eleventh-century church of Wuqro Cherqos in East Tigray, Ethiopia. My paper identifies the origin of this misunderstood fragment and presents it in the longue durée, from its architectural placement as part of an inscribed arch in the great mosque of a Fatimid trading colony to its medieval spoliation and use as a chancel arch in the church of Wuqro Cherqos, after northern Ethiopia emerged as a centralized power under the Zagwe dynasty. As the chancel in Wuqro Cherqos, the stone took on new meaning as a luxurious liturgical threshold, complementing the Egyptian and Indian silks that hung alongside it. After the arch came apart in the late 1990s, I show how modern Ethiopian scholars promoted the remaining Arabic-inscribed fragment as an ancient Ethiopian inscription. The life story of this stone fragment reveals a larger picture of Islam’s changing reception in Ethiopia from the Middle Ages to the twenty-first century.
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Melita, Lucia Noor, Katarzyna Węgłowska, Diego Tamburini, and Capucine Korenberg. "Investigating the Potential of the Er:YAG Laser for the Removal of Cemented Dust from Limestone and Painted Plaster." Coatings 10, no. 11 (November 17, 2020): 1099. http://dx.doi.org/10.3390/coatings10111099.
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A successful application of Er:YAG laser for the cleaning of a restored Assyrian relief sculpture from the British Museum collection is presented. Displayed in the gallery, the sculpture has darkened over time due to the natural deposition of dirt, in particular on restored parts. Since traditional cleaning methods have demonstrated to be unsuccessful, a scientific investigation was performed to identify the composition of the soiling and the materials used for the restoration. The analysis suggested the presence of gypsum, calcium oxalate, carbonates and alumino-silicates on the encrustation. The molded plaster, composed of lime and gypsum and pigmented aggregates, was likely prepared at the end of the 19th century to mimic the stone color. It was repainted with what was identified as a modern oil-based overpaint, applied to cover darkening during a second conservation treatment in the 20th century. Laser trials were first performed on small areas of the objects and on mock-ups to determine the critical fluence thresholds of the surface, investigated through visual examination and analyses using Fourier transform infrared spectroscopy (FTIR) and Pyrolysis-gas chromatography-mass spectrometry (Py–GC–MS). The right parameters and conditions to be used during the cleaning process were, therefore, determined. The chemical selectivity of the cleaning process allowed us to complete the treatment safely while preserving the restoration.
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Mwangi, Fredah Wanjiku, Peterson Warutere, and Anthony W. Nyambura. "Exposure to respirable dust and factors associated with abnormal pulmonary function among stone diggers in Kayole quarries, Nairobi City County, Kenya." International Journal Of Community Medicine And Public Health 10, no. 4 (March 29, 2023): 1302–7. http://dx.doi.org/10.18203/2394-6040.ijcmph20230904.
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Background: In Kenya, the quarry industry suffers several constraints: some quarry workers get injured, others get chronic diseases, while some die. This study assessed occupational exposure to respirable dust and factors associated with abnormal pulmonary function among quarry stone diggers in Mihang’o and Matopeni quarries in Kayole Nairobi City County, Kenya. Methods: The study was done in Mihang’o and Matopeni quarries. An analytical cross-sectional design was used and a sample size of 165 respondents was taken. An interviewer administered semi structured questionnaire. Spirometry tests were done by a qualified technician to assess pulmonary function. Respirable dust levels were determined with the aid of a particle counter. Descriptive statistics like frequency, means were used to summarize data and results were presented in frequency tables and graphs. Chi square tests and logistic regression were done. T tests were done to compare the means of dust levels in the two quarries. Results: This study found the daily mean levels of PM2.5 and PM10 were higher than the levels recommended by WHO. The age of the respondents, presence of respiratory symptoms, years of work experience, nostril covering, and smoking were factors associated with abnormal pulmonary function at (p≤0.05). Conclusions: In conclusion, chronic exposure to quarry dust increases the risk of developing respiratory symptoms and abnormal pulmonary function. This study recommended that routine particulate matter monitoring should be done in Nairobi quarries to provide data that can inform decisions on air pollution control actions.
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Xie, Jun, Zhihu Wang, Fusong Wang, Shaopeng Wu, Zongwu Chen, and Chao Yang. "The Life Cycle Energy Consumption and Emissions of Asphalt Pavement Incorporating Basic Oxygen Furnace Slag by Comparative Study." Sustainability 13, no. 8 (April 19, 2021): 4540. http://dx.doi.org/10.3390/su13084540.
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Basic Oxygen Furnace Slag (BOF), as alternatives for aggregate in asphalt pavement construction, is beneficial to the environment by reducing land occupation and resource consumption. However, the quantitative effects on energy consumption and emissions reduction remains poorly understood due to the unavailability of local life cycle inventory. Therefore, its LCI needs to be built by accounting for the properties of BOF aggregate in terms of high porosity and dust content in BOF, the rainy interference condition that reducing efficiency in production, and transportation distance. Here we investigated the life cycle energy consumption and global warming potential (CO2-eq emission) of asphalt pavement incorporating BOF aggregate by performing a case study with uncertainty analysis. Five scenarios were elaborated and performed in the case study. The results show that the energy required for BOF production is 0.024 MJ/kg, approximately half the energy required for crushed stone of 0.044 MJ/kg. The pavements with BOF can reduce up to 12% of emission compared to ordinary pavement. Considerably more negative impacts of rainy weather on energy consumption of BOF than natural crushed stone can be concluded. Monte Carlo simulation indicates that the order of magnitudes of the energy values were varied, from materials extraction as the maximum contributor to transportation. The benefits for BOF utilization are gradually offset by increased transport distances and the displacement ratios of fine crushed stones, due to the increase in fuel and resource consumption for mixing, construction, and transportation.
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Dewangan, Arvind, and D. P. Gupta. "SIGNIFICANCE OF MARBLE AND PORTLAND CEMENT." International Journal of Engineering Technologies and Management Research 5, no. 2 (February 10, 2020): 255–65. http://dx.doi.org/10.29121/ijetmr.v5.i2.2018.170.
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The aim of this current study is both to avoid the environmental. In this way, we will help to protect the environment by consuming the waste marble dust obtained as a by- product of marble sawing and shaping processes in the factories those operating in our region. Stone industry is an important factor in worldwide economy. Despite this, a large amount of residues is produced in ornamental stone industry with different dimension and particle size. The increasing rate at which raw material are continuously transformed into industrial products results in waste generation. Consequently, recycling of industrial wastes and byproducts is becoming a crucial demand by the environmental laws in agreement with the concept of sustainable development. The present study was therefore planned to explore the possibility of usage of waste marble powder (WMP) as partial replacement of sand for production of concrete This research work is concerned with the experimental investigation on strength of concrete and optimum percentage of the partial replacement by replacing (OPC) cement via 0%, 10%, 12.5%, 15%, 17.5% and 20% of stone waste. Keeping all this view, the aim of the investigation is the behavior of concrete while replacing of waste with different proportions of stone waste in concrete by using tests like compression strength.
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Samukov, A. D. "Complex Recycling of Crushed Aggregates Waste." Ecology and Industry of Russia 23, no. 7 (July 19, 2019): 15–19. http://dx.doi.org/10.18412/1816-0395-2019-7-15-19.
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The problem of the formation and processing of waste in the production of crushing stone for road construction is considered. An integrated approach is proposed, which implies both a reduction in the amount of waste generated and its subsequent processing to obtain products in demand on the market. The technologies based on the use of vibration equipment and allowing to obtain qualified products from crushing screenings are described: cubical crushed aggregates, high-quality fractionated artificial sand and vibro pressed products based on it. The possible options for recycling the dust-like component of the waste with the production of lightweight aggregate for concrete and mineral wool are given. An estimate of the predicted environmental effect of preventing the disposal of waste from the production of crushing stone for road construction, subject to the application of the proposed technologies, is given.
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Choudhary, Jayvant, Brind Kumar, and Ankit Gupta. "Utilization of Waste Glass Powder and Glass Composite Fillers in Asphalt Pavements." Advances in Civil Engineering 2021 (October 13, 2021): 1–17. http://dx.doi.org/10.1155/2021/3235223.
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Today, researchers around the globe are looking for suitable alternatives of conventional fillers which can form flexible pavements with satisfactory engineering performance in an environmental friendly and cost-effective manner. This study investigated the engineering, economical, and environmental viability of recycling waste glass powder (GP) and glass-hydrated lime (GL) composite as alternative fillers, in place of stone dust (SD). All fillers were characterized, and asphalt concrete mixes incorporating them at different proportions (4–8.5%) were designed using the Marshall mix design method. The engineering performance of asphalt mixes was analyzed using the static creep analysis, indirect tensile fatigue test, Cantabro test, modified Lottman test, resilient modulus test, mixing time analysis, and boiling water test. Additionally, the design of single km of two-lane flexible pavements utilizing aforesaid mixes was done as per the mechanistically empirical method suggested in IRC 37 guideline. Finally, the economic and environmental analysis was done by comparing their material cost and global warming potential (GWP). GL and GP mixes exhibited better resistance against rutting, fatigue, and low temperature cracking at lower optimum asphalt content than SD mixes. However, GP mixes also displayed poor moisture resistance and adhesion due to the high amount of silica in GP. GL mixes had satisfactory moisture resistance up to 7% filler content due to the fine nature and anti-stripping properties of hydrated lime. The pavement containing GL and GP fillers also reduced material cost and GWP up to 35% while consuming up to 74 tons of GP.
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Solanki, Vidhya, Karishma Barot, and Priyanka Chaudhari. "Pulmonary Function Impairment among Stone Cutting Workers in North Gujarat." International Journal of Health Sciences and Research 11, no. 6 (June 10, 2021): 39–46. http://dx.doi.org/10.52403/ijhsr.20210607.
Повний текст джерелаАнотація:
Background: Pulmonary problems are a major cause of morbidity & mortality all over the world. It has been found that lung functions are mostly affected in workers exposed to affect majorly in granite, marble, various other rocks and sand dust exposed workers. Objective:The primary objective of the study was to find out the prevalence of pulmonary function impairment among stone cutting workers at various construction sites in North Gujarat and the secondary objective was to find the effectiveness of Physiotherapy measures among those workers. Methods: A total of 408 male stone cutting worker participated in this study around various construction sites in the vicinity of North Gujarat from September to December 2019. After assessing pulmonary function tests, workers with impairment were treated with Deep breathing exercise and advice personal protective measures like face masks, cession of smoking and water spraying before cutting. Results: The data was collected from all the stone cutting workers. The average age was 31.43 ± 9.18 years and the average duration of work experience as stone cutter was 12.32± 6.11. A total of 50.24 % participant complaints of chronic cough, 10.29% of chest pain and 31.61% of participants reported wheezes. Data Analysis showed after 3 months of Physiotherapeutic intervention there was significant difference in FEV1 FVC and FEV1/FVC. Conclusion:The present study shows that there was a high prevalence of pulmonary functions impairment among stone cutting worker in North Gujarat and Physiotherapy measures can be used as an adjacent to minimize this problem. Key words: Stone cutting workers, Pulmonary Function impairment, Pulmonary Function test, North Gujarat.
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Braine, Jonathan, Fatemeh Tabatabaei та Manolis Xilouris. "Dust emission from the atomic and molecular gas in M 33: a changing β". Proceedings of the International Astronomical Union 10, H16 (серпень 2012): 617. http://dx.doi.org/10.1017/s1743921314012460.
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AbstractWe use the very recently completed high-resolution IRAM CO survey of M33 with the high-resolution HI observations (published by Gratier et al. 2010, A&A, 522, 3) and Herschel Far-IR and submillimeter mapping observations to study how the dust behaves in the molecular and atomic gas phases of the interstellar medium (ISM). M33 is a “young" object in that it is gas-rich with a young stellar population and low metallicity as compared to large spirals like the Milky Way or Andromeda. Nonetheless, it is very clearly a spiral galaxy with a thin and reasonably axisymmetric disk. As such, it can be viewed as a stepping stone towards less evolved objects like magellanic irregulars (including the LMC and SMC) and perhaps distant objects in the early universe. More specifically, we look for radial variations in the dust emission spectrum (β parameter) as well as comparing regions dominated by either H2 or HI. The grey-body emission spectrum flattens (lower β) with galactocentric distance and generally is flatter in the atomic medium as compared to the molecular gas.
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Stanwell, R. E., J. M. Stuart, A. O. Hughes, P. Robinson, M. B. Griffin, and K. Cartwright. "Smoking, the environment and meningococcal disease: a case control study." Epidemiology and Infection 112, no. 2 (April 1994): 315–28. http://dx.doi.org/10.1017/s0950268800057733.
Повний текст джерелаАнотація:
SUMMARYThis case control study investigated environmental factors in 74 confirmed cases of meningococcal disease (MD). In children aged under 5, passive smoking in the home (30 or more cigarettes daily) was associated with an odds ratio (OR) of 7.5 (95% confidence interval (CI) 1.46–38.66). ORs increased both with the numbers of cigarettes smoked and with the number of smokers in the household, suggesting a dose–response relationship. MD in this age group was also significantly associated with household overcrowding (more than 1.5 persons per room) (OR 6.0, 95% CI 1.10–32.8), with kisses on the mouth with 4 or more contacts in the previous 2 weeks (OR 2.46, 95% CI 1.09–5.56), with exposure to dust from plaster, brick or stone in the previous 2 weeks (OR 2.24, 95% CI 1.07–4.65); and with changes in residence (OR 3.0, 95% CI 1.0–8.99), marital arguments (OR 3.0, 95 % CI 1.26–7.17) and legal disputes in the previous 6 months (OR 3.10, 95% CI 1.24–7.78). These associations were independent of social class. Public health measures to lower the prevalence of cigarette smoking by parents of young children may reduce the incidence of MD. The influence of building dust and stressful life events merits further investigation.
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Chiruţă, Ciprian, Ioana Mădălina Tănasă, Iulian Alin RoȘu, Ovidiu Gelu Tudose, BrânduȘa SluȘer, and Marius Mihai Cazacu. "Case Study of the Evidence of PM1& PM2.5 Contribution on PM10 from Podul De Piatra– Iasi City." BULETINUL INSTITUTULUI POLITEHNIC DIN IAȘI. Secția Matematica. Mecanică Teoretică. Fizică 68, no. 1 (March 1, 2022): 49–54. http://dx.doi.org/10.2478/bipmf-2022-0004.
Повний текст джерелаАнотація:
Abstract The importance of air quality monitoring has been strongly demonstrated in numerous scientific studies. This study, carried out in an intense circular intersection, brings additional arguments that the monitoring of the fine particles like PM1 and PM2.5 that influence in more than 80% the concentration of PM10 particles must be measured at several points. Few were the cases [approx. 20%] in which the increase of PM10 concentrations is given by particles with diameters from 2.5 to 10 μm, most likely caused by the re-suspension of dust particles. Grimm Aerosol Technik Germany and SC INOESY SRL conducted a campaign for monitoring the air quality [PM1, PM2.5, PM10] in Iasi, Stone Bridge area, from 8 to 22 February 2018. The monitoring point was located close (150 m) to the APMIS-01 station of the National Environmental Protection Agency.
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Nanjegowda, Vinay Hosahally, M. N. Rathankumar, and N. Anirudh. "Fillers Influence on Hot-Mix Asphalt Mixture Design and Performance Assessment." IOP Conference Series: Earth and Environmental Science 1149, no. 1 (May 1, 2023): 012013. http://dx.doi.org/10.1088/1755-1315/1149/1/012013.
Повний текст джерелаАнотація:
Abstract Filler’s presence in hot-mix asphalt (HMA) is even though minimal but they do affect its durability characteristics. Many natural and waste materials in the form of fillers have been studied for their effectiveness on HMA mix design and performance characteristics. However, in practice, stone dust (SD) is the preferred filler due to its abundance, ease of availability, and cost-effectiveness. Thus, the major objective of this study was to investigate the effect of locally available materials: stone dust (SD)- natural, hydrated lime (HL) – processed, rice-husk ash (RHA) and fly-ash (FHA)-waste materials on HMA properties based on the factors such as availability, field utilization, cost, and sustainability, while at the same time identify the anomalies of those selected fillers on HMA mix if any. A viscosity grade (VG-30) binder was selected and checked for its fundamental consistency characteristics set forth in Indian standards. In this study, aggregate gradation structure specified as bituminous concrete grading 1 (BC1) in India was designed for the preparation and evaluation of four HMA mixes: (a) BC1 with SD (BC1-SD), (b) BC1 with RHA (BC1-RHA), (c) BC1 with FA (BC1-FA), and d) BC1 with HL (BC1-HL). Fillers: RHA, FA, and HL were studied for their physico-chemical properties. The most recommended filler dosage of 4% by weight of mix was selected and kept uniform for the various BC1 mixes. Marshall method of mix design was performed to identify the optimum asphalt content (OAC) of four different BC1 mixes. The test results of methylene blue value (MBV), german filler value (GFV), and fineness modulus (FM) indicated that RHA includes more micron-to-nano sized particles than the other two fillers (HL and FA). The scanning electron microscope coupled with energy dispersive X-ray results showed that the RHA and FA exhibited similar chemical composition, while HL was identified to be a calcium-based compound. The BC1-RHA mix resulted in non-cohesive mix for the binder content ranging from 4.5 to 6.5%. Additionally, for the binder contents in the range of 7 to 9% the BC1-RHA compacted samples failed to yield air voids of 4% required to arrive at the OAC. The BC1- FA mix showed the highest Marshall stability (26.97 KN) followed by BC1-HL (23.97 kN), and BC1-SD (17.9 kN). Also, retained stability test results of all the three different mixes were in close proximity to each other indicative of the affinity of the fillers to asphalt. The resistance to moisture susceptibility results indicated that HL is the better anti-stripping element followed by FA, and SD. Among the three different filler-based BC1 mixes, BC1-HL mix was adjudged as an effective moisture resistant mix followed by BC1-FA, and BC1-SD. However, a single filler that not only tends to improve the various performance parameters of the mix but be available in abundance and cost-effective is yet to be explored.
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Tandup, Cherring, Lileswar Kaman, and Saroj Kant Sinha. "Surgical management of the impacted dormia basket during ERCP." International Surgery Journal 6, no. 5 (April 29, 2019): 1783. http://dx.doi.org/10.18203/2349-2902.isj20191908.
Повний текст джерелаАнотація:
The incidence of associated common bile duct stones in patients undergoing cholecystectomy is 10%. The present day management of common bile duct stone is pre- or post-operative endoscopic retrograde cholangio-pancreatography and clearance of common bile duct. Complications of ERCP and CBD stone extraction have been reported to occur in 5 to 10% cases which may range from mild to life threatenin Here we report a case of cholelithiasis with choledocholithiasis with obstructive jaundice and patient while undergoing ERCP and stone retrieval had complication of impacted dormia basket which was managed by surgery.
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Sedik, Alaaeldin Mohamed, Abrar Hussein, Abdelmajid Alshimary, Mostafa Elsayed, Ahmed Alzayed, and Nada Alharbi. "Post-ERCP Dormia basket impaction: a case report and literature review." International Surgery Journal 8, no. 12 (November 26, 2021): 3692. http://dx.doi.org/10.18203/2349-2902.isj20214765.
Повний текст джерелаАнотація:
The incidence of Common bile duct stones (CBD) in patients undergoing cholecystectomy is 10%. The present-day management of common bile duct stone may be pre-, intra-, or post-operative Endoscopic retrograde cholangio-pancreatography (ERCP) with stone extraction. The reported complications of ERCP and CBD stone extraction range from 5 to 10% cases, that might be life threatening. Herein, we reported a case of calculus obstructive jaundice and cholangitis. Unfortunately, trials for ERCP and stone retrieval was followed by impacted Dormia basket which was successfully managed by surgerys.
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Traxer, Olivier, and Mariela Corrales. "Managing Urolithiasis with Thulium Fiber Laser: Updated Real-Life Results—A Systematic Review." Journal of Clinical Medicine 10, no. 15 (July 30, 2021): 3390. http://dx.doi.org/10.3390/jcm10153390.
Повний текст джерелаАнотація:
Thirty-three years ago, pulsed lasers marked the beginning of a new era in endoscopic lithotripsy, and the one that was highlighted because of its potential was the Holmium: YAG laser, which became and still is the gold standard in endourology. Recently, a new laser technology has been accepted for clinical use in lithotripsy: the thulium fiber laser (TFL), showing appealing characteristics not seen before in several preclinical studies. A review of the literature was performed and all relevant in vitro studies and clinical trials until April 2021 were selected. The search came back with 27 clinical experiences (7 full-text clinical trials and 20 peer-reviewed abstracts) and 33 laboratory studies (18 full-text articles and 15 peer-reviewed abstracts). The clinical experiences confirmed the clinical safety of using the wide parameter range of the TFL. This technology demonstrated the performance at a higher ablation speed, the higher ablation efficiency, and the better dust quality of the TFL, as well as reduced stone retropulsion, thus helping to maintain an optimal visibility. No thermal or radiation damage was found. Given the current evidence, we may be facing the future gold standard laser in endoscopic lithotripsy.