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1
Ray, Arpan, Radhikesh Prasad Nanda, and Pronab Roy. "Rutting Performance of Road Using Construction and Demolition Waste Materials." Key Engineering Materials 882 (April 2021): 221–27. http://dx.doi.org/10.4028/www.scientific.net/kem.882.221.
Повний текст джерелаАнотація:
Wastes arising from construction and demolition (C & D) constitute one of the major streams in many countries. In this paper experimental investigation was carried to see the feasibility of C& D waste as road aggregates. From the grading analysis it was observed that using C& D wastes, strength criteria is being satisfied and meet the specifications of MORTH which is then subjected to aggregate impact value (AIV) testing, CBR testing etc. The CBR value of C&D waste was found to be 43.46 which were well above the permissible value. A proposed three-layer system using soil layer, C & D waste layer and asphalt concrete layer is chosen to estimate rut depth using existing analytical model. From the analytical model rut depth is predicted to be 14.77 mm which is less then maximum allowable limits. Hence C& D waste materials can be used as alternate materials in road construction with economy and sustainability.
2
Saimanova, Olga, Svetlana Teplykh, and Vadim Alpatov. "Methods of organizing work on construction and demolition waste recycling." BIO Web of Conferences 43 (2022): 03018. http://dx.doi.org/10.1051/bioconf/20224303018.
Повний текст джерелаАнотація:
The research is aimed at finding new ways that contribute to environmental improvement. It is evident that there is a great need at the moment to find optimal methods of construction and demolition waste recycling while renovating urban areas. The researchers examine the recycling method which is characterized as one of the most effective ways to solve the problem of construction waste disposal. In this paper the authors resort to the method of comparison as well as to graphical, tabular, and abstract-logical methods. They analyze two main methods used to carry out recycling operations: the first method involves recycling waste at the site of construction using mobile crushing plants and the second involves recycling at stationary crushing and grading complexes. Then the authors point out advantages and disadvantages of these methods and examine the efficiency of a stationary complex. The researchers also calculate the prime cost of construction waste processing at a stationary crushing and grading complex and its payback period. It is concluded that the use of a stationary complex for construction and demolition waste recycling is technically and economically feasible.
3
Bolzonella, D., P. Pavan, P. Battistoni, and F. Cecchi. "Anaerobic co-digestion of sludge with other organic wastes and phosphorus reclamation in wastewater treatment plants for biological nutrients removal." Water Science and Technology 53, no. 12 (June 1, 2006): 177–86. http://dx.doi.org/10.2166/wst.2006.420.
Повний текст джерелаАнотація:
This paper deals with the performances obtained in full scale anaerobic digesters co-digesting waste activated sludge from biological nutrients removal wastewater treatment plants, together with different types of organic wastes (solid and liquid). Results showed that the biogas production can be increased from 4,000 to some 18,000 m3 per month when treating some 3–5 tons per day of organic municipal solid waste together with waste activated sludge. On the other hand, the specific biogas production was improved, passing from 0.3 to 0.5 m3 per kgVS fed the reactor, when treating liquid effluents from cheese factories. The addition of the co-substrates gave minimal increases in the organic loading rate while the hydraulic retention time remained constant. Further, the potentiality of the struvite crystallisation process for treating anaerobic supernatant rich in nitrogen and phosphorus was studied: 80% removal of phosphorus was observed in all the tested conditions. In conclusion, a possible layout is proposed for designing or up-grading wastewater treatment plants for biological nutrients removal process.
4
Mohd Pauzi, Nurul Noraziemah, Maslina Jamil, Roszilah Hamid, and Muhammad Fauzi Mohd Zain. "Influence of Morphology of Cathode-Ray Tube Glass as Coarse Aggregates on Compressive Strength and Water Absorption of Concrete." Solid State Phenomena 280 (August 2018): 399–409. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.399.
Повний текст джерелаАнотація:
The study on the substitution for natural coarse aggregates using waste CRT funnel glass in spherically shapes is still limited. In this paper, the waste CRT glass has been processed to form a spherical CRT glass (GS) and crushed CRT glass (GC), which were used as a coarse aggregate in concrete production. Results indicated that the inclusion of GS and GC has lower the compressive strength and decreased the rate of capillary water absorption of concrete. It was demonstrated that the morphology properties of GS and GC (shape, surface texture, size, grading) is significantly affected the concrete properties.
5
Zhou, Yingwu, Yitao Weng, Limiao Li, Biao Hu, Xiaoxu Huang, and Zhongfeng Zhu. "Recycled GFRP Aggregate Concrete Considering Aggregate Grading: Compressive Behavior and Stress–Strain Modeling." Polymers 14, no. 3 (January 31, 2022): 581. http://dx.doi.org/10.3390/polym14030581.
Повний текст джерелаАнотація:
Fiber-reinforced polymer (FRP) composites have been used in various industries, thus a large amount of FRP wastes have been generated due to the out-of-service of FRP products. Recycling FRP wastes into coarse aggregates to replace natural coarse aggregates (NCA) to form the recycled FRP aggregate concrete (RFAC) is a potential approach to dispose of huge quantities of FRP wastes with low environmental impact. In this paper, waste glass FRP (GFRP) bars were cut into particles of 12 sizes to enable the grading of recycled FRP aggregate (RFA) as similar as possible to that of NAC. The influence of different RFA volume replacement ratios (0%, 30%, 50%, 70%, 100%) on the compressive performance of RFAC was investigated based on uniaxial compression tests of 15 standard cylinders. The results showed that the failure mode of RFAC was different from that of NAC. As the RFA replacement ratio increased, the compressive strength and elastic modulus of the RFAC gradually decreased, but its post-peak brittleness was significantly mitigated compared to NAC. The Poisson’s ratio of RFAC increased with the increase in the RGFA replacement ratio at the elastic stage and was smaller than that of NCA concrete. Both the existing stress–strain models developed for NAC and recycled aggregate concrete (RAC) were found not fit for the RFAC. Thus, a new stress–strain model that was applicable to RFAC was developed by modifying the classical existing model, and a good agreement between the model predictions and test data was reached.
6
Mao, Peng Jun, Lu Liu, Jun Wang, and Chun Yan Hu. "A Study on Gray Relational Analysis of Many Factor Weights in Tobacco Leaves Classification." Advanced Materials Research 139-141 (October 2010): 1728–31. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1728.
Повний текст джерелаАнотація:
For the nine characteristic factors of tobacco leaf grading standards have different degree of influence on final grading results and lack of objective evaluation method, in this paper, we applied the gray relational analysis method to determine the weight of tobacco leaf factors in every grade, which calculate the gray relational analysis of nine characteristic factors: such as hue, lightness value, chroma, length, leaf structure, waste, oil, maturity and body. The gray relation was normalized to get the weight of the nine factors in tobacco leaf classification. By contrasted with the subjective evaluation of five experts in tobacco field, the calculation results are basically consistent with the experts’ recommendation. It illustrates that the application of Grey relational method to calculate influence ability of flue-cured tobacco grading factors is feasible. This method eliminates the subjectivity of the weight of each factor and can make the results more realistic.
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Gerges, Najib Nicolas, Camille Amine Issa, Samer Ahmad Fawaz, Jacques Jabbour, Johnny Jreige, and Aiman Yacoub. "Recycled Glass Concrete: Coarse and Fine Aggregates." European Journal of Engineering Research and Science 3, no. 1 (January 19, 2018): 1. http://dx.doi.org/10.24018/ejers.2018.3.1.533.
Повний текст джерелаАнотація:
Conventional concrete aggregate consists of sand (fine aggregate) and various sizes and shapes of gravel or stones (coarse aggregate). However, there is a growing interest in substituting alternative aggregate materials, largely as a potential use for recycled materials. While there is significant research on many different materials for aggregate substitutes such as granulated coal ash, blast furnace slag or various solid wastes including fiberglass waste materials, granulated plastics, paper and wood products or wastes, sintered sludge pellets and others. Recycled waste glasses were used as coarse and fine aggregates replacement in concrete. Coarse aggregates were replaced with Green Bottles coarse aggregates at third, half, two thirds, and 100% replacement ratios. The replacement of a third coarse aggregate was established as being the most suitable for retaining the properties of the concrete mix design. As for fine aggregates, in order to account for the numbers of variables and clearly establish a bench mark, the sand grading, color of glass, source of waste glass (bottles and non-bottles), and design mix strength were used as parameters. Fine aggregates from green, brown, and transparent bottles in addition to clear window waste glass were used. Concrete properties were tested in fresh and hardened states. The incorporation of glass sand regardless of the ratios of replacement showed no significant influence on fresh or mechanical properties of concrete except for the case of transparent bottles. Transparent bottles due to the wide source of obtainability have introduced a non-uniform factor that caused discrepancy compared to the rest of the group.
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Gerges, Najib Nicolas, Camille Amine Issa, Samer Ahmad Fawaz, Jacques Jabbour, Johnny Jreige, and Aiman Yacoub. "Recycled Glass Concrete: Coarse and Fine Aggregates." European Journal of Engineering and Technology Research 3, no. 1 (January 19, 2018): 1–9. http://dx.doi.org/10.24018/ejeng.2018.3.1.533.
Повний текст джерелаАнотація:
Conventional concrete aggregate consists of sand (fine aggregate) and various sizes and shapes of gravel or stones (coarse aggregate). However, there is a growing interest in substituting alternative aggregate materials, largely as a potential use for recycled materials. While there is significant research on many different materials for aggregate substitutes such as granulated coal ash, blast furnace slag or various solid wastes including fiberglass waste materials, granulated plastics, paper and wood products or wastes, sintered sludge pellets and others. Recycled waste glasses were used as coarse and fine aggregates replacement in concrete. Coarse aggregates were replaced with Green Bottles coarse aggregates at third, half, two thirds, and 100% replacement ratios. The replacement of a third coarse aggregate was established as being the most suitable for retaining the properties of the concrete mix design. As for fine aggregates, in order to account for the numbers of variables and clearly establish a bench mark, the sand grading, color of glass, source of waste glass (bottles and non-bottles), and design mix strength were used as parameters. Fine aggregates from green, brown, and transparent bottles in addition to clear window waste glass were used. Concrete properties were tested in fresh and hardened states. The incorporation of glass sand regardless of the ratios of replacement showed no significant influence on fresh or mechanical properties of concrete except for the case of transparent bottles. Transparent bottles due to the wide source of obtainability have introduced a non-uniform factor that caused discrepancy compared to the rest of the group.
9
Zhou, Wenfei, Huiling Du, Le Kang, Xian Du, Yupu Shi, Xiaojing Qiang, Haodong Li, and Jing Zhao. "Microstructure Evolution and Improved Permeability of Ceramic Waste-Based Bricks." Materials 15, no. 3 (January 31, 2022): 1130. http://dx.doi.org/10.3390/ma15031130.
Повний текст джерелаАнотація:
The resource and large-scale utilization of waste ceramic materials, magnesium slag, and coal gangue are one of the important ways for the sustainable development in metallurgy, coal, and other related enterprises. In this paper, waste ceramic materials were used as aggregates; coal gangue and magnesium slag were used as mixed binder; and the all solid-waste-based permeable bricks with excellent performance were prepared by forming pressure at 5 MPa. The mechanical properties and water permeability of the all-solid-waste-based permeable bricks were evaluated. The results proved that the porous channel of permeable brick is mainly composed of waste ceramic materials with a particle size of 2–3 mm. Pore structures below 200 μm were mainly composed of fine aggregate and mixed binder. Using 60% coarse aggregate, 20% fine aggregate, 10% coal gangue, and 10% magnesium slag as raw materials, the all-solid-waste-based permeable bricks were obtained by pressing at 6 MPa and sintering at 1200 °C, which exhibited the best performance, and its water permeability, compressive strength, and apparent porosity were 1.56 × 10−2 cm/s, 35.45 MPa, and 13.15%, respectively. Excellent water permeability, compressive strength, and apparent porosity of the all solid-waste-based permeable bricks were ascribed to the high content of connecting open pores, and closely adhesive force were ascribed to the porous microstructure constructed by the grading of waste ceramic materials and the tight conjoined points of the liquid phases in coal gangue and magnesium slag at a high sintering temperature.
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Wang, Yong Yi, and Lin Li. "Environment Pollution and Control Strategy for Exploitation of Asbestos Mine." Advanced Materials Research 726-731 (August 2013): 1845–49. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1845.
Повний текст джерелаАнотація:
To control environment pollution by exploitation of asbestos mine and forming of tailing pond effectively and provide decision-making basis to competent authorities, the paper analyzed the causes for asbestos powder pollution in course of exploitation of asbestos mine and tailing pond of asbestos through field investigation and research. Slow exploitation and grading process of asbestos mine and shortage of management were the root causes for environment pollution by asbestos, and the tailing pond of asbestos resulted in resources waste and pollution of the atmosphere, water and land. The government should regulate in terms policy, industrial planning etc. offer economic support, change the backward exploitation process, perform comprehensive resources utilization and utilize asbestos properly.
11
Ye, Gang. "Method of Mix Design for Hot Recycled Asphalt Mixtures." Applied Mechanics and Materials 584-586 (July 2014): 1062–65. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1062.
Повний текст джерелаАнотація:
Hot recycled asphalt mixtures are used more widely in road construction and reconstruction at present. The recycle of asphalts can reuse the waste asphalts and bring economic benefits. Meanwhile it can protect the environment and save the energy. The mix design is an important step for regeneration of the old asphalts. And it is critical to the performance of hot recycled asphalt mixtures. This paper illustrates the mechanism of hot recycling of asphalts and proposes a simple and useful method of mix design for hot recycled asphalt mixtures. In the process, the performances and grading of reclaimed materials were evaluated. And the composition of raw materials with different contents were tested for selection of the best mix. The results show that the method is feasible by practise.
12
Ding, Le, Junhui Zhang, Bowen Feng, and Cheng Li. "Performance Evaluation of Recycled Asphalt Mixtures Containing Construction and Demolition Waste Applicated as Pavement Base." Advances in Civil Engineering 2020 (July 23, 2020): 1–11. http://dx.doi.org/10.1155/2020/8875402.
Повний текст джерелаАнотація:
Construction and demolition waste contain large amount of concrete and bricks. To identify its feasibility of applying in asphalt stabilized gravel mixtures as pavement base, this paper carried out researches on properties of recycled asphalt mixture (RAM) by laboratory testing, under different contents of recycled aggregates (RA) and proportions of bricks to concrete. First, the basic physical properties of each component of the RAM were determined. According to the actual screening passing rate, the Bailey method was used to design and verify the grading of RAM, and then initial asphalt content was estimated. The stability, flow value, voidage, and bulk density were obtained by Marshall Test, and the optimal asphalt-aggregate ratios were determined under different RA contents and proportion of bricks to concrete. Subsequently, the uniaxial compression test, splitting tensile test, immersion Marshall test, freeze-thaw splitting test, and Hamburg rutting test were performed to investigate mechanical properties, water stability, and high-temperature stability of RAM. The results shows that as the content of RA increases from 0% to 100%, the corresponding compressive strength, resilient modulus, and splitting tensile strength all decrease; the same change trend is presented in the residual stability and freeze-thaw splitting test strength ratio and rutting depth. According to the requirement of pavement base of high-grade roads in China’s standards, the recommended RA content and proportion of bricks to concrete were proposed for the design RAM.
13
Horan, William, and Bernadette O’Regan. "Developing a Practical Framework of Sustainability Indicators Relevant to All Higher Education Institutions to Enable Meaningful International Rankings." Sustainability 13, no. 2 (January 11, 2021): 629. http://dx.doi.org/10.3390/su13020629.
Повний текст джерелаАнотація:
Higher Education Institutions (HEIs) sustainability assessments are receiving significant attention in the academic literature, with ever more complex grading and ranking systems being developed. This paper aims to provide national policy makers with a simple set of indicators to facilitate measuring progress towards sustainability for the HEI sector, within the context of national sustainability data collection efforts. Candidate indicators were identified and assessed from the two most subscribed to HEI sustainability assessments, namely, the UIGreenMetric and STARS, to develop a sector specific indicator set. This resulted in a final set of 12 indicators, covering on-site energy, greenhouse gas emissions, solid waste, water, travel, education, research, and governance. The proposed indicator set was then compared to publicly available data for Irish HEIs, to identify gaps in data collection, which found that direct campus energy use and associated Scope 1 and 2 emission data alone were collected with sufficient rigour. The described indicator set has the potential to be applied to guiding national sustainability transitions globally and offers a template for accelerating sustainability data collection efforts for the HEI sector.
14
Horan, William, and Bernadette O’Regan. "Developing a Practical Framework of Sustainability Indicators Relevant to All Higher Education Institutions to Enable Meaningful International Rankings." Sustainability 13, no. 2 (January 11, 2021): 629. http://dx.doi.org/10.3390/su13020629.
Повний текст джерелаАнотація:
Higher Education Institutions (HEIs) sustainability assessments are receiving significant attention in the academic literature, with ever more complex grading and ranking systems being developed. This paper aims to provide national policy makers with a simple set of indicators to facilitate measuring progress towards sustainability for the HEI sector, within the context of national sustainability data collection efforts. Candidate indicators were identified and assessed from the two most subscribed to HEI sustainability assessments, namely, the UIGreenMetric and STARS, to develop a sector specific indicator set. This resulted in a final set of 12 indicators, covering on-site energy, greenhouse gas emissions, solid waste, water, travel, education, research, and governance. The proposed indicator set was then compared to publicly available data for Irish HEIs, to identify gaps in data collection, which found that direct campus energy use and associated Scope 1 and 2 emission data alone were collected with sufficient rigour. The described indicator set has the potential to be applied to guiding national sustainability transitions globally and offers a template for accelerating sustainability data collection efforts for the HEI sector.
15
Fang, Yiming, Xianxin Guo, Kun Chen, Zhu Zhou, and Qing Ye. "Accurate and automated detection of surface knots on sawn timbers using YOLO-V5 model." BioResources 16, no. 3 (June 10, 2021): 5390–406. http://dx.doi.org/10.15376/biores.16.3.5390-5406.
Повний текст джерелаАнотація:
Knot detection is a challenging problem for the wood industry. Traditional methodologies depend heavily on the features selected manually and therefore were not always accurate due to the variety of knot appearances. This paper proposes an automated framework for addressing the aforementioned problem by using the state-of-the-art YOLO-v5 (the fifth version of You Only Look Once) detector. The features of surface knots were learned and extracted adaptively, and then the knot defects were identified accurately even though the knots vary in terms of color and texture. The proposed method was compared with YOLO-v3 SPP and Faster R-CNN on two datasets. Experimental results demonstrated that YOLO-v5 model achieved the best performance for detecting surface knot defects. F-Score on Dataset 1 was 91.7% and that of Dataset 2 was up to 97.7%. Moreover, YOLO-v5 has clear advantages in terms of training speed and the size of the weight file. These advantages made YOLO-v5 more suitable for the detection of surface knots on sawn timbers and potential for timber grading.
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Shen, Zhaoyu, Yuhang He, Usama Sayed, Jun Wang, Yuhao Zhou, and Zheng Wang. "Measurement of the elastic constants of carbon fiber board based on modal analysis." BioResources 17, no. 1 (November 17, 2021): 255–68. http://dx.doi.org/10.15376/biores.17.1.255-268.
Повний текст джерелаАнотація:
As a strategic new material with excellent performance, carbon fiber has attracted much attention in the wood structure industry. In this paper, the test modal and computational modal analysis methods are used to study the mode shape and modal parameters of carbon fiber board, calculate the elastic constants, i.e., the elastic modulus, shear modulus, and Poisson’s ratio, and analyze the coupling of the results. The conclusions show that the numerical results of the mode shape and elastic constants of the carbon fiber board obtained via the computational modal and test modal analysis are highly coupled. The first-order bending and first-order torsional modes of the carbon fiber board obtained via the two analysis methods are consistent, and the frequency error rate is less than 5%. The error rates of the elastic modulus and shear modulus are 0.7% and 7.8%, respectively. In addition, the research is conducive to strengthening the work of finite element computational modal analysis, and better promoting the application of non-destructive testing and quality grading of carbon fiber board. The above-mentioned optimization design work for improving the dynamic characteristics of carbon fiber board, and further research on the detection and optimization of the performance when the carbon fiber material is combined with wood, also has engineering application value for promoting the faster development of the wood structure market.
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Reisinger, Julia, Stefan Kugler, Iva Kovacic, and Maximilian Knoll. "Parametric Optimization and Decision Support Model Framework for Life Cycle Cost Analysis and Life Cycle Assessment of Flexible Industrial Building Structures Integrating Production Planning." Buildings 12, no. 2 (February 2, 2022): 162. http://dx.doi.org/10.3390/buildings12020162.
Повний текст джерелаАнотація:
Most industrial buildings have a very short lifespan due to frequently changing production processes. The load-bearing structure severely limits the flexibility of industrial buildings and is a major contributor to their costs, carbon footprint and waste. This paper presents a parametric optimization and decision support (POD) model framework that enables automated structural analysis and simultaneous calculation of life cycle cost (LCC), life cycle assessment (LCA), recycling potential and flexibility assessment. A method for integrating production planning into early structural design extends the framework to consider the impact of changing production processes on the footprint of building structures already at an early design stage. With the introduction of a novel grading system, design teams can quickly compare the performance of different building variants to improve decision making. The POD model framework is tested by means of a variant study on a pilot project from a food and hygiene production facility. The results demonstrate the effectiveness of the framework for identifying potential economic and environmental savings, specifying alternative building materials, and finding low-impact industrial structures and enclosure variants. When comparing the examined building variants, significant differences in the LCC (63%), global warming potential (62%) and flexibility (55%) of the structural designs were identified. In future research, a multi-objective optimization algorithm will be implemented to automate the design search and thus improve the decision-making process.
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Raheem, Akeem A., and Bolanle Deborah Ikotun. "Investigation of Workability and Compressive Strength of Wood Ash Cement Concrete Containing Nanosilica." Advanced Materials Research 1154 (June 2019): 129–36. http://dx.doi.org/10.4028/www.scientific.net/amr.1154.129.
Повний текст джерелаАнотація:
Studies have revealed that wood ash cement concrete just like other pozzolanic cement concrete has lower early strength compared to plain cement concrete. Nanoparticles have been found to improve the early strength of concrete due to its small size and large surface area. This paper reports the findings on influence of nanosilica on the workability and compressive strength of wood ash cement concrete. Wood ash was obtained as a waste product from Ladoke Akintola University of Technology (LAUTECH) bread bakery, Ogbomoso. Biological synthesis of nanosilica using kola pod extract and silica precursor (1:5) was conducted at Nanotechnology research group laboratory at LAUTECH. The chemical composition, specific gravity and grading of wood ash, fine and coarse aggregate used were determined. Concrete with 10% wood ash replacement for cement was produced using 1:2:4 mix proportion and water to binder ratio of 0.5. Nanosilica was added at 0.5, 1.0, 1.5 and 2.0% levels. Concrete with no wood ash and nanosilica served as the control. Workability and compressive strength of the plain and composite concrete were determined. The results showed that concrete workability was enhanced with introduction of nanosilica. The compressive strength also increased with the addition of nanosilica. Maximum compressive strength of 27.53MPa was achieved at 90 days with 1.5% nanosilica addition. It was concluded that nanosilica enhanced workability and improved both early and later strength development in wood ash concrete with 1.5% as the optimum addition.
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Duan, Shaowei, Wenzhao Zhou, Xinglong Liu, Jian Yuan, and Zhifeng Wang. "Experimental Study on the Bending Behavior of Steel-Wood Composite Beams." Advances in Civil Engineering 2021 (June 26, 2021): 1–12. http://dx.doi.org/10.1155/2021/1315849.
Повний текст джерелаАнотація:
This paper proposes a steel-wood composite beam with H-shaped steel beam webs glued to the wood. As a new type of composite beam, it combines the advantages of low energy consumption of wood, high permeability, and less pollution and the advantages of light weight and high strength of steel, high degree of assembly, short construction period, and less construction waste generated. Carrying out research is of great significance to improve the mechanical properties of steel-wood composite beams and promote the development of steel-wood composite structures. In this paper, three hot-rolled H-beam-larch composite beams and one pure steel beam were tested for bending capacity. The composite beams are divided into two different combinations of A and B types. The two sides of the web are connected with larch wood by structural glue to form a composite beam. The type B composite beam is a larch wood glued on both sides of the H-shaped steel web and penetrates the bolts at the same time. Through the three-point monotonic static grading loading of the composite beam, the deflection change, failure phenomenon, and form of the specimen during the experiment were observed. Under the circumstances, the ultimate bearing capacity of the test piece was changed to study the combined effect of larch and hot-rolled H-shaped steel. The results show that the overall performance of the H-shaped steel-larch composite beam is good. Bonding wooden boards on both sides of the steel beam web can improve the bearing capacity, and the form of the member is more reasonable and effective; increasing the cross-sectional size of the H-beam in the steel-wood composite beam can further improve the bearing capacity of the composite beam; adding bolt anchorage on the basis of the structural glue used in the composite beam can further improve the bearing capacity of the composite beam. The superposition principle is used to simplify the calculation of the ultimate bearing capacity of H-shaped steel-larch composite beams. Comparing the calculation results with the test results, the data are in good agreement, which can provide a design reference for the practical application of such composite beams.
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Darko-Koomson, Samuel, Robert Aidoo, and Tahirou Abdoulaye. "Analysis of cassava value chain in Ghana: implications for upgrading smallholder supply systems." Journal of Agribusiness in Developing and Emerging Economies 10, no. 2 (April 14, 2020): 217–35. http://dx.doi.org/10.1108/jadee-05-2019-0066.
Повний текст джерелаАнотація:
PurposeCommercialization of cassava is increasing because of increased urban demand for processed products and increased recognition of the industrial potential of the crop. This study aims to examine the cassava value chain in Ghana and its implications for upgrading.Design/methodology/approachA combination of purposive, simple random and snowball sampling methods was adopted to select key actors in the cassava value chain. A semi-structured questionnaire was used to collect primary data. Analysis of the data was largely descriptive, except for profitability of cassava production in selected regions, which was examined by employing gross and net marketing margin analysis. A comprehensive value chain map was generated to show the different product pathways for cassava from the farm gate to the final consumer, and roles of key value chain actors and their relationships were summarized through simple narrations.FindingsEvidence has shown chains of more than four different channels through which fresh cassava roots move from the farm gate to final consumers. Production of cassava in Ghana is profitable, generating positive net marketing margins across major producing centres. Processing of cassava has both dry and wet/fresh value chains depending on the derived products for the final consumer. There is weak governance system in the cassava value chain in Ghana as majority of actors use spot market transactions in dealing with trading partners. The use of standardized grading and weighing system is very limited in the chain, and limited access to credit is a critical constraint to value chain upgrading.Research limitations/implicationsWith the exception of results from the profitability analysis of producers, the findings on marketing margins of other value chain actors may not be generalizable. Future studies could determine the profitability associated with cassava value-adding activities like processing into various forms and explore the possibility of converting waste from processing into energy.Practical implicationsThe study includes implications that focus on product and process upgrading efforts by smallholders in the cassava value chain. This paper recommends innovative financing models for smallholders to improve access to microcredit via internal and external funding sources.Originality/valueThis paper reveals specific intervention areas in which smallholders can direct efforts in an attempt to improve the cassava value chain through product, process and functional upgrading.
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Song, Shou Xu, Ji Ru Zhao, and Tao Liu. "The Prediction for the Residual Life of Waste Drive Axle Housing Basing on Neural Network." Advanced Materials Research 308-310 (August 2011): 246–50. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.246.
Повний текст джерелаАнотація:
In order to estimate the residual life of waste drive axle housing, the prediction model of waste axle housings with artificial neural networks is built in this paper. Take the deformation, residual stress and the gradient of magnetic intensity Kmax relating to axle housing’s fatigue damage degree as the input of neural network, and compare the testing residual life of the waste drive axle housing with its predicting residual life. The result demonstrates that: the deformation, residual stress and the gradient of magnetic intensity Kmax of axle housing as the characteristic parameter estimating the degree of fatigue damage, adopting trainbr training function can get good network performance and comparatively high precision of prediction. Besides, the longer the residual life of the waste axle housing is, the more precise the prediction life will be.
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Earl, Dennis. "Two Years of Specifications Grading in Philosophy." Teaching Philosophy 45, no. 1 (2022): 23–64. http://dx.doi.org/10.5840/teachphil20211118154.
Повний текст джерелаАнотація:
Points-based grading, though now traditional, faces powerful critiques: Such grading creates a low road to passing, it undermines motivation, it wastes time, and it causes stress. It creates an illusion of mathematical precision. It is unfriendly to necessary conditions for satisfactory performance. This paper defends the alternative of specifications grading. Specifications grading grades only on whether work meets a set of expectations for satisfactory performance, with the expectations set at a high but reachable level. With a high bar also comes opportunities to revise unsatisfactory work. I summarize arguments from the literature in support of the system, but I also give account of my two-year experiment in philosophy courses with specifications grading. Compared with points-based grading, specifications grading appears to motivate students better and helps them learn more. I consider objections from both traditionalists and so-called ‘ungraders.’ The former hope to secure the benefits of specifications grading while still keeping points. The latter favor eliminating grading altogether.
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Xin, Chunlin, Lingjie Wang, Bin Liu, Yu-Hsi Yuan, and Sang-Bing Tsai. "An Empirical Study for Green Transportation Scheme of Municipal Solid Waste Based on Complex Data Model Analysis." Mathematical Problems in Engineering 2021 (April 8, 2021): 1–17. http://dx.doi.org/10.1155/2021/6614312.
Повний текст джерелаАнотація:
Solid waste management and air pollution are two pressing issues in the functioning of large cities. This paper studies the optimization problem of the green transportation route of municipal solid waste and establishes a mathematical planning model based on real-time traffic conditions of the city and consideration of a time window and multiple transfer stations with the goal of minimizing energy consumption. In the optimal green transportation process in this paper, comprehensive consideration of vehicle speed, vehicle load, road gradient, and driving distance in different road sections based on real-time traffic conditions is incorporated, which has a better fuel-saving potential than the shortest path. A green transportation program can alleviate the air pollution problem in big cities and promote energy conservation and emission reduction in solid waste transportation.
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Singh, Manpreet, Priyankar Choudhary, Anterpreet Kaur Bedi, Saurav Yadav, and Rishi Singh Chhabra. "Compressive Strength Estimation of Waste Marble Powder Incorporated Concrete Using Regression Modelling." Coatings 13, no. 1 (December 30, 2022): 66. http://dx.doi.org/10.3390/coatings13010066.
Повний текст джерелаАнотація:
A tremendous volumetric increase in waste marble powder as industrial waste has recently resulted in high environmental concerns of water, soil and air pollution. In this paper, we exploit the capabilities of machine learning to compressive strength prediction of concrete incorporating waste marble powder for future use. Experimentation has been carried out using different compositions of waste marble powder in concrete and varying water binder ratios of 0.35, 0.40 and 0.45 for the analysis. Effect of different dosages of superplasticizer has also been considered. In this paper, different regression algorithms to analyse the effect of waste marble powder on concrete, viz., multiple linear regression, K-nearest neighbour, support vector regression, decision tree, random forest, extra trees and gradient boosting, have been exploited and their efficacies have been compared using various statistical metrics. Experiments reveal random forest as the best model for compressive strength prediction with an R2 value of 0.926 and mean absolute error of 1.608. Further, shapley additive explanations and variance inflation factor analysis showcase the capabilities of the best achieved regression model in optimizing the use of marble powder as partial replacement of cement in concrete.
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Yamasoto, Keita, Yuki Osakabe, Sota Adachi, Shinji Munetoh, and Osamu Furukimi. "A Novel Electric Power Generation Mechanism from Waste Heat without Temperature Gradient." MRS Advances 1, no. 60 (2016): 3941–46. http://dx.doi.org/10.1557/adv.2016.292.
Повний текст джерелаАнотація:
ABSTRACTSeebeck effect is widely used for the energy harvesting from wasted heat. In the Seebeck effect, the electric power can be generated by the temperature difference between both ends of the thermoelectric materials. However, low conversion efficiency is caused by heat flux from hot side to cold side of sample. In this paper, we have proposed a new thermal power generation mechanism with no temperature difference. We investigated the band structure of Ba8AuxSi46-x clathrate single crystal synthesized by Czochralski method. The single crystal has a gradient of the gold contents along the growth direction. According to the results of Seebeck coefficient, the electrical properties of the Ba8AuxSi46-x clathrate dramatically changed depending on the gold contents. In the case of gold content of lower than 5.33, the Ba8AuxSi46-x clathrate showed a n-type semiconductor. In the case of gold content of higher than 5.33, the Ba8AuxSi46-x clathrate showed a p-type semiconductor. The band gap of the n-type and p-type Ba8AuxSi46-x clathrate were wider than the intrinsic semiconductor. We can successfully synthesize a n-p junction single crystal, which obtaining energy band curve generated from the difference of Fermi level between p- and n- type semiconductors. The single crystal was heated under the uniform temperature and able to obtain generated electric voltage of around 0.6 mV at 400°C. These results suggested that the obtained electric voltage can be generated from the separation of hole-electron pair excited by heating at the intrinsic part with a narrow band gap along to the energy band curve formed by p-n junction.
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Lu, Shaoguang, and D. Yogi Goswami. "Optimization of a Novel Combined Power/Refrigeration Thermodynamic Cycle." Journal of Solar Energy Engineering 125, no. 2 (May 1, 2003): 212–17. http://dx.doi.org/10.1115/1.1562950.
Повний текст джерелаАнотація:
A novel combined power/refrigeration thermodynamic cycle is optimized for thermal performance in this paper. The cycle uses ammonia-water binary mixture as a working fluid and can be driven by various heat sources, such as solar, geothermal, and low temperature waste heat. The optimization program, which is based on the Generalized Reduced Gradient algorithm, can be used to optimize for different objective functions. In addition, cycle performance over a range of ambient temperatures was investigated.
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Liu, Gang, Yuanji Li, Pan Wei, Tian Xiao, Xiangzhao Meng, and Xiaohu Yang. "Thermo-Economic Assessments on a Heat Storage Tank Filled with Graded Metal Foam." Energies 15, no. 19 (September 30, 2022): 7213. http://dx.doi.org/10.3390/en15197213.
Повний текст джерелаАнотація:
To save and better deploy waste heat, the use of a mobilized heat storage system (MHSS) with phase change enhancement means is developed. In this paper, three kinds of gradient structures (positive gradient, negative gradient, and non-gradient) are designed in the MHSS system. The uniform porosity is 94% in the non-gradient structure, and the gradient porosities are 86%, 93%, and 98% in the gradient structure, respectively. Numerical models are developed to explore the contribution of the graded metal foam structure to the heat storage and release process. An economic analysis and comparison of MHSS systems with different heat transfer models are carried out. The results show that the positive gradient case can promote the thermal cycle of the melting and solidification process, while the negative gradient case inhibits the thermal cycle. The positive gradient case can reduce the melting time by 9.7% and the solidification time by 4.4%, while the negative gradient can prolong the melting time by 31.4% and the solidification time by 35.9%. Although graded metal foam increases the initial investment by 76.09%, the 1 KW·h heat cost of graded metal foam is reduced by 10.63% compared to pure phase change material (PCM). It is cost-effective in the long run of thermal cycles.
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Kodikara, J. K., and F. Rahman. "Effects of specimen consolidation on the laboratory hydraulic conductivity measurement." Canadian Geotechnical Journal 39, no. 4 (August 1, 2002): 908–23. http://dx.doi.org/10.1139/t02-036.
Повний текст джерелаАнотація:
Laboratory hydraulic conductivity tests are commonly used for the design of clayey liners in waste containment. Although relatively small hydraulic gradients are encountered under field conditions, elevated gradients are desirable to reduce the testing time. It is generally believed, however, that these elevated gradients would reduce the conductivity measured owing to specimen consolidation. In the current paper a theoretical analysis is presented for assessing the effect of specimen consolidation. The theoretical results were compared with experimental results obtained for two local soils. Parametric analyses and nondimensional analyses were carried out and the results are presented. It was found that the hydraulic conductivity is dependent on the type of permeameter, the form of gradient application, and the state of stress within the soil. It was apparent that hydraulic conductivity can decrease with an increase in the hydraulic gradient, and the decrease was not significant up to a hydraulic gradient of about 300 for the soils tested.Key words: hydraulic conductivity, hydraulic gradient, specimen consolidation, volume change, permeameter.
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Golovkina, Anna, Dmitri Ovsyannikov, and Sorin Olaru. "Performance optimization of radioactive waste transmutation in accelerator driven system." Cybernetics and Physics, Volume 7, 2018, Number 4 (December 23, 2018): 210–15. http://dx.doi.org/10.35470/2226-4116-2018-7-4-210-215.
Повний текст джерелаАнотація:
Long-lived actinides transmutation in accelerator driven system (ADS) is considered in this paper. The objective is to improve the transmutation performance from the overall radiotoxity of nuclear waste point of view by means of an optimization approach based on control theory. Parameters subjected to determination are the initial values of actinides nuclear concentration in the loaded fuel. The change in time of actinides’ atomic concentration is described by a system of ordinary differential equations with initial conditions, that can be given with some inaccuracy. For such dynamical system a gradient-based optimization algorithm taking into account robustness of initial loading will be constructed. Moreover, constraint on value of effective multiplication factor is considered during numerical optimization. Based on this approach initial atomic concentration values providing the best indicators of actinides burnup can be obtained. Calculation results of actinides volume fraction and effective multiplication factor dynamics are presented.
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Li, Yingjie, and Lianjun Chen. "Improved LSTM data analysis system for IoT-based smart classroom." Journal of Intelligent & Fuzzy Systems 39, no. 4 (October 21, 2020): 5141–48. http://dx.doi.org/10.3233/jifs-179999.
Повний текст джерелаАнотація:
To reduce the resource and energy waste of colleges and universities more accurately and efficiently, this paper has developed a smart classroom data analysis system based on the Internet of Things, which realizes a variety of sensor information (temperature, humidity, smoke). Environmental parameters such as carbon dioxide concentration and light intensity), remote collection of equipment information, data storage and data analysis functions, and intelligent control of smart classrooms. Data analysis uses an improved LSTM model to predict energy consumption. The model uses LSTM and bidirectional LSTM and uses the ELU activation function instead of the sigmoid and tanh activation functions of the LSTM. Compared with the standard LSTM model and the LSTM model without the ELU activation function, the model improves the prediction accuracy, better avoid the gradient disappearance, and reduces the over-fitting. The system implementation results show that the system can effectively reduce school energy waste.
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Miecznik, Magdalena, Jerzy, Wojciech Mietelski, Edyta Łokas, and Krzysztof Kleszcz. "Modeling of the Cs137 and Sr90 contamination transportation process performed for the vicinity of National Radioactive Wastes Disposal in Różan (NE Poland)." Computer Science and Mathematical Modelling, no. 7/2018 (July 18, 2018): 19–30. http://dx.doi.org/10.5604/01.3001.0012.2002.
Повний текст джерелаАнотація:
This paper contains the results of radionuclides transportation modeling under National Radioactive Waste Disposal (NRWD) grounds in Różan (northeast Poland). The disposal is of the low- and intermediate-level waste (LILW) type. We simulated the radionuclides transportation process through sandy soils. The simulation was performed in a self-written simulator in Scilab using the finite difference method. The model included diffusion, advection and radioactive decay. The model was tested according to convergence and stability. Assuming the hydrological gradient being 0.008, the contamination transportation time was 30–46 years depending on the modeled problem. The modeled distance of 600 m was from underneath the disposal to the exudation in the Narew ravine. Radioactive decay for both cesium (Cs137) and strontium (Sr90) had a significant impact on the results. The model proved to be a useful tool for performing simple scientific simulations. This survey was part of a PhD thesis.
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Chen, Fengbin, Jiguang Liu, Xiaowei Zhang, Jinxing Wang, Huazhe Jiao, and Jianxin Yu. "Review on the Art of Roof Contacting in Cemented Waste Backfill Technology in a Metal Mine." Minerals 12, no. 6 (June 4, 2022): 721. http://dx.doi.org/10.3390/min12060721.
Повний текст джерелаАнотація:
The backfilling mining method can effectively solve the environmental and safety problems caused by mining. It is the key technology to realize green mining. Scientific development has accelerated the pace of research on the rational utilization of mine solid waste and improved the research level of backfilling technology. The development history of the backfilling mining method is introduced in the present paper, and it is determined that roof-contacting backfilling is the key technology of mine-solid-waste backfilling mining. This paper introduces three calculation methods of similar roof-contacted backfilling rates. In this paper, the relationship between the characteristics of backfilling slurry made from solid waste from mines and the roof-contacted backfilling rate is systematically analyzed, such as the flow law in stope (gravity gradient), bleeding shrinkage, and natural sedimentation of backfilling slurry. It is pointed out that the characteristics of the stope, such as washing-pipe water, water for the leading way, filling pipeline, and shape of the backfilling stope, are closely related to the roof-contacted backfilling rate. The influential relationship between objective factors, such as human factors, limited auxiliary leveling measures, and backfilling “one-time operation” in the backfilling process, and high-efficiency top filling are considered, and a schematic diagram of the influencing top-filling rate and structure is drawn. At the same time, this paper summarizes the improvement measures of roof connection from three aspects. These include the use of expansive non-shrinkable materials, forced roof-contacted technology, and strengthening management level. It is pointed out that the roof-contacted filling technology is still facing severe challenges, and the research on the backfilling connection technology needs to be strengthened.
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Lezhnev, Sergey N., Abdrakhman B. Naizabekov, and Evgeniy Panin. "Radial-Shear Rolling as a New Technological Solution for Recycling Bar Scrap of Ferrous Metals." Materials Science Forum 1052 (February 3, 2022): 498–503. http://dx.doi.org/10.4028/p-dtc7hm.
Повний текст джерелаАнотація:
Recycling of waste, both ferrous and non-ferrous metals is a useful process for the economy of any country. In this paper, a new technology for recycling bar scrap of ferrous metals by rolling on radial-shear rolling mills was proposed to obtain a marketable product in the form of bars with an ultrafine-grained gradient structure. Studies have shown that the deformation of the rod of scrap pieces of rebar from steel 18G2S mill of radial-shear rolling can significantly dispersed structure with obtaining the gradient ultrafine-grained structure, and this in turn leads to an increase of the mechanical characteristics of this steel grade. Thus, the tensile strength of steel grade 18G2S deformed at the radial-shear rolling mill was 620 MPa (at the initial value of 365 MPa).
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Lezhnev, S. N., A. B. Naizabekov, I. E. Volokitina, E. A. Panin, and E. I. Kuldeyev. "Radial-shear rolling as a new technological solution for recycling bar scrap of ferrous metals." Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 316, no. 1 (March 15, 2021): 46–52. http://dx.doi.org/10.31643/2021/6445.06.
Повний текст джерелаАнотація:
Waste recycling of both ferrous and non-ferrous metals is a useful process for the economy of any country. This paper proposes a new technology for recycling bar scrap of ferrous metals by rolling it in radial-shear rolling mills by producing a commercial product in the form of bars with an ultrafine-grained gradient structure. Studies have shown that the deformation of bar scrap in the form of pieces of reinforcement made of steel grade 18G2S in a radial-shear rolling mill makes it possible to significantly disperse its structure by producing a gradient ultrafine-grained structure, and this, in turn, leads to the elevating of the mechanical characteristics of this steel grade. Thus, the tensile limit of the 18G2S grade steel deformed on the radial-shear rolling mill was 620 MPa (at the initial value of 365 MPa).
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Nunez, Itzel, Afshin Marani, and Moncef L. Nehdi. "Mixture Optimization of Recycled Aggregate Concrete Using Hybrid Machine Learning Model." Materials 13, no. 19 (September 29, 2020): 4331. http://dx.doi.org/10.3390/ma13194331.
Повний текст джерелаАнотація:
Recycled aggregate concrete (RAC) contributes to mitigating the depletion of natural aggregates, alleviating the carbon footprint of concrete construction, and averting the landfilling of colossal amounts of construction and demolition waste. However, complexities in the mixture optimization of RAC due to the variability of recycled aggregates and lack of accuracy in estimating its compressive strength require novel and sophisticated techniques. This paper aims at developing state-of-the-art machine learning models to predict the RAC compressive strength and optimize its mixture design. Results show that the developed models including Gaussian processes, deep learning, and gradient boosting regression achieved robust predictive performance, with the gradient boosting regression trees yielding highest prediction accuracy. Furthermore, a particle swarm optimization coupled with gradient boosting regression trees model was developed to optimize the mixture design of RAC for various compressive strength classes. The hybrid model achieved cost-saving RAC mixture designs with lower environmental footprint for different target compressive strength classes. The model could be further harvested to achieve sustainable concrete with optimal recycled aggregate content, least cost, and least environmental footprint.
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Avetisyan, A. R., O. O. Korchagina, and L. V. Matveev. "Model of a Thermally Induced Liquid Inclusion Migration in a Single Crystal of Halites under a Homogeneous Temperature Gradient Field." Radioactive Waste 19, no. 2 (2022): 100–104. http://dx.doi.org/10.25283/2587-9707-2022-2-100-104.
Повний текст джерелаАнотація:
The paper focuses on an evolution model developed for a liquid inclusion in halites under a temperature gradient field, taking into account surface phenomena. To demonstrate the safety of heat-generating radioactive waste disposal in salt rocks (halites), thermally induced migration of liquid inclusions should be studied. Based on the study, a software package was developed providing numerical implementation of this model. The diffusion equation with initial and boundary conditions was approximated via the finite element method on triangular unstructured mobile grids. In case of weak formulation, the equations were discretized and solved in the FEniCS software. The study showed good agreement between the calculations and the experimental data.
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Iatcheva, Ilona, Rumena Stancheva, Georgi Kunov, and Irish Jordanian. "Shape identification in a magnetic separation system." Facta universitatis - series: Electronics and Energetics 23, no. 2 (2010): 159–67. http://dx.doi.org/10.2298/fuee1002159i.
Повний текст джерелаАнотація:
The present paper deals with a problem of shape identification in a magnetic separation system, used for separation of useful metal pieces from waste materials. The aim is to increase the productiveness of separation process. The effectiveness of the magnetic separator work is estimated on the basis of specific magnetic force, acting in the working zone of the device. This specific force depends on the magnetic field strength and its gradient. The forward problem of electromagnetic field determination has been solved using finite element method and Quickened 5.6 software package. The specific force determination and solution of the identification problem is realized in MATLOW.
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Черьопкіна, Р. І., І. В. Трембус та І. М. Дейкун. "НАПІВФАБРИКАТИ ІЗ НЕДЕРЕВНОЇ СИРОВИНИ ДЛЯ ВИГОТОВЛЕННЯ ПАПЕРУ". Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 148, № 4 (10 березня 2021): 140–48. http://dx.doi.org/10.30857/1813-6796.2020.4.13.
Повний текст джерелаАнотація:
The main objectives of scientific work is to study the technological parameters of the sodium hydroxide method of delignification of non-wood raw materials and production of fibrous first stuff for the manufacturing of packaging types of paper. Methodology. For the research, rapeseed stalks, sodium hydroxide cooking, anthraquinone catalyst were used. The brews were cooked in steel autoclaves, which were lowered into a glycerin bath. Standard methods for the determination of the quality indicators (yield and residual lignin content) of non-wood fiber first stuff were used. As a mathematical data processing method, the generalized reduced gradient method was used. Laboratory samples of castings of fibrous first stuff and paper were made on a LA-2 sheet-making apparatus, the mechanical parameters of the outturn sheet were determined according to the standard methods using appropriate instruments. Results. The expediency of using rapeseed stalks for processing of fibrous first stuff under alkaline conditions has been proven. It was found that the greatest influence on the delignification of raw materials has the raise of cooking temperature from 80 to 120 ° C and the use of the anthraquinone catalyst. It has been shown that the obtained rapeseed first stuff have sufficient paper-forming properties and are suitable for use in the production of MS 5B brand paper for the use in the production of fluting paper or board of B-3 grade. The scientific novelty of the work is due to the environmental friendliness of the agrowaste processing as an alternative raw material for the production of fibrous first stuff at low cooking temperatures. Using rapeseed stalks as an example, the influence of technological parameters on the quality indicators of first stuff was studied. Using the mathematical methods of the processing of experiment data, the optimal ratio of fibrous first stuff /waste paper at which the strength indicators of fluting paper or board will meet the standards was determined. Practical significance. Research results has shown the expediency of using oilseed wastes for processing of fibrous first stuff , with the aim of expanding the raw material base of cardboard and paper production.
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Mahmoud, Hanan Ahmed Hosni, Nada Ali Hakami, and Alaaeldin M. Hafez. "An Intelligent Deep Learning Model for CO 2 Adsorption Prediction." Adsorption Science & Technology 2022 (May 11, 2022): 1–15. http://dx.doi.org/10.1155/2022/8136302.
Повний текст джерелаАнотація:
In this paper, we propose a supervised deep learning neural network (D-CNN) approach to predict CO2 adsorption form the textural and compositional features of biomass porous carbon waste and adsorption features. Both the textural and compositional features of biomass porous carbon waste are utilized as inputs for the D-CNN architecture. A deep learning neural network (D-CNN) is proposed to predict the adsorption rate of CO 2 on zeolites. The adsorbed amount will be classified and predicted by the D-CNN. Three tree machine learning models, namely, gradient decision model (GDM), scalable boosting tree model (SBT), and gradient variant decision tree model (GVD), were fused. A feature importance metric was proposed using feature permutation, and the effect of each feature on the target output variable was investigated. The important extracted features from the three employed model were fused and used as the fusion feature set in our proposed model: fusion matrix deep learning model (FMDL). A dataset of 1400 data items, on adsorbent type and various adsorption pressure, is used as inputs for the D-CNN model. Comparison of the proposed model is done against the three tree models, which utilizes a single training layer. The error measure of the D-CNN and the tree model architectures utilize the mean square error confirming the efficiency of 0.00003 for our model, 0.00062 for the SBT, 0.00091 for the GDM, and 0.00098 for the GVD, after 150 epochs. The produced weight matrix was able to predict the CO 2 adsorption under diverse process settings with high accuracy of 96.4%.
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Zi Feng, Lim, and Lim Joon Hoong. "Effect of temperature mismatch on the life cycle of thermoelectric generator efficiency for waste heat recovery." MATEC Web of Conferences 335 (2021): 03010. http://dx.doi.org/10.1051/matecconf/202133503010.
Повний текст джерелаАнотація:
Global warming due to greenhouse gases that has been produced by energy generator as a byproduct has becoming a serious issue in recent decades. Thermoelectric module is an alternative method that can generate energy from heat and vice versa. The module is denominated as thermoelectric generator (TEG) when it is used to generate electricity via a process called the Seebeck effect. The use of thermoelectric generator has become more and more demanding due to the low maintenance cost and waste heat availability can be found everywhere in daily life such as car exhaust, roof tiles, and etc. The purpose of this research paper was to determine the effect of temperature mismatch on the life cycle of the thermoelectric generator efficiency using ANSYS simulation. The common used materials for the thermoelectric are bismuth telluride, lead telluride and silicon germanium. Each material has different thermal conductivity, Seebeck coefficient and electrical resistivity. The materials are paired together to form a thermocouple and the thermal gradient of the TEG is being evaluate through the simulation. Generally, the greater the temperature between the hot and cold side of the TEG, the higher the power generated. Bismuth telluride has a highest temperature difference between the hot and cold side followed by lead telluride and silicon germanium. The combination of BiTe(N) - BiTe(P) has the lowest minimum heat flux compared to the rest of the thermoelectric material combination. This proves that thermal and electrical properties and combination of thermoelectric material plays a vital role in the thermal gradient of the TEG.
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Kellner, E., and E. C. Pires. "The influence of thermal stratification on the hydraulic behavior of waste stabilization ponds." Water Science and Technology 45, no. 1 (January 1, 2002): 41–48. http://dx.doi.org/10.2166/wst.2002.0006.
Повний текст джерелаАнотація:
Thermal stratification, which is characterized by a high vertical thermal gradient, is usually observed in deep lakes. However, although waste stabilization ponds have small depths, their high turbidity provides favorable conditions for the occurrence of this phenomenon, mainly during summer. During that time of the year, the layers nearest to the surface concentrate a larger amount of thermal energy compared to the deeper layers, which results in a temperature difference between the surface and the bottom of the pond. As a consequence a density profile appears, with the less dense layers located at the surface of the pond and the densest ones close to the bottom. This stratification in the water column induces alterations in the flow pattern and a decrease of the useful volume of the pond. This paper presents a mathematical model developed to forecast the conditions of thermal stratification in waste stabilization ponds and the volume actually used for wastewater treatment. With these values it is possible to correct the average residence time of the liquid in the pond. The theoretical results were compared with experimental observations, and maximum differences of 15% between the calculated and observed temperature profiles were found.
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Diawo, Joe. "Training Needs Analyses of Cocoa Farmers in Kailahun District." International Journal of Scientific and Management Research 05, no. 10 (2022): 121–55. http://dx.doi.org/10.37502/ijsmr.2022.51010.
Повний текст джерелаАнотація:
This research analyses the training needs of cocoa farmers in eight chiefdoms in Kailahun District, Eastern Sierra Leone. The paper is an in depth examination of the training needs of the target population in order to bridge the information gap in the existing literature. The objectives of the research were to describe the socio-economic characteristics of cocoa farmers in Kailahun District, analyse their training preferences in areas of cultivation, harvest, post-harvest and marketing practices taking into consideration what knowledge and skills they need to have, when to have them, where and how to have them and ascertain the perception of cocoa farmers in the district on training. The findings reveal that cocoa is grown by both male and female cocoa farmers, more adults aged 36-55 than youth aged 18-36 and the aged, 55 and above were involved in cocoa production in the district, 85.4% of cocoa farmers in the district were married compared to the widowed, 10%; divorced, 1.9%; and single, 2.7%., almost all the male cocoa farmers were polygamous and had many children as labour sources required for work on the cocoa farms, majority of the farmers have been in cocoa farming for a minimum of five years. More than 50% of the farmers had more than one cocoa plantation, the combined acreage of the cocoa farms owned by more than 50% of the farmers was over five acres per farmer, more cocoa farmers (60%) as opposed to 39.7% accepted having received training on various aspects of cocoa farming, major sources of training received were dealers, colleague cocoa farmers, others like development partners interested in cash crop farming, most of the trainings conducted lasted between 1-4 days (29.8%) and 5-10 days (20.5%), a good number of the farmers claimed to have been trained in many of the areas of cocoa farming, though 31.3% of the farmers claimed not to have received any training, the most preferred training method identified by the farmers was on the farm demonstration, the most preferred time of training was in the morning, more youth and adults claimed to have received training in recent times than the aged, cocoa farmers needed training in sorting of dried cocoa beans, grading, cocoa certification, price determination of cocoa, standard number of shade trees per hectare of cocoa, preferable times for under-brushing, strategies for pest management and reasons for the low price of cocoa from Sierra Leone, cocoa farmers had a positive perception about the following: significance of training for cocoa farmers, appropriate spacing of cocoa trees to increase yield, regular under-brushing of cocoa farms to minimise competition with weeds for nutrients, promote easy movement across the farm, reduce pests and increase yield, cultural justification of child labour, gender imbalance tilted in favour of men, the need for women to know and have a say about the use of proceeds from the sale of cocoa, the need for farmers to produce quality cocoa to attract better prices, the need to ferment and thoroughly dry cocoa to attract better prices, the need for proper waste management on cocoa farms, the need to harvest and break the pods to remove the seeds using the right tools, the need to rehabilitate aging cocoa plantations, and the need to keep cocoa beans in jute bags instead of nylon bags, their perceptions about the following were however negative: child labour, the need to grow cocoa on suitable soil, waste management on cocoa farms and the need for care in harvesting and breaking of cocoa pods and the need to keep cocoa separate from other items among others. It is concluded that cocoa farmers in Kailahun District have had training in several aspects of cocoa farming, but still genuinely have training needs that should be addressed. This is because in the first place, a good number of the farmers have never had an opportunity to be trained in any aspect of cocoa farming. Second, even those who have benefitted from one training or the other still require refresher training or training in other aspects of cocoa farming that they have not received training in. Third, the world is dynamic and as such, new knowledge and farming techniques come up regularly that need to trickle down to farmers in the field so that the required impact is created on the sector. These can be done through training the cocoa farmers. It is recommended that farmers should enroll with adult education institutions for some form of adult education in Numeracy, Literacy, record keeping, soil conservation and other related areas for which training. This, coupled with the training by extension agents can enhance their knowledge and skills in cocoa production, increase the quantity and quality of the yield, raise the quantum of their earnings and their standard of living; the Ministry of Agriculture in collaboration with the Ministry of Technical and Higher Education and development partners in agriculture and technical and higher education should take the lead in providing the training opportunities for cocoa farmers by establishing adult education centres in rural communities so that farmers do not envisage many problems attending the classes; farmers who have proven to be resistant to accepting innovations should be encouraged to adopt new technics, new methods of cocoa production and cultivate new and high yielding cocoa varieties; the Amazon variety was found to be creating the desired impact of cultivation among cocoa farmers in the district.
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Guo, Zi Rui, Yi Sun, Li Ran Yue, and Yong Feng Li. "Hydrogen Recovery from Organic Wastes: Reactor Development and Improvement." Advanced Materials Research 113-116 (June 2010): 1040–44. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.1040.
Повний текст джерелаАнотація:
The paper reviewed hydrogen production biotechnology on reactor development and design aspects. Biological hydrogen-producing reactor as acid-producing phase of two-phase anaerobic organism treatment system plays an important role in the following aspects: Reactor was developed as the follow ideas: a. CSTR-type anaerobic fermentation reactor is selected to reduce the substrate concentration in reactor and increase target product operational yield and selectivity in the reactor; b. mixture liquid in reaction area is stirred by the stirrer to reach a turbulent state in order to reduce interfacial layer thickness and temperature gradient in a floc unit particle and increase mass transfer rate; c. H2 in the particle and Liquid phase is accelerated to release to prevent accumulated H2 from bringing feedback inhibition to organism metabolism, and H2/CO2conversion to acetic acid; d. A sector turbine agitator with hoisting capacity and mixing power is selected to facilitate sludge to flow back through a effluence seam.
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Du, Yanan, Haiqiang Fu, Lin Liu, Guangcai Feng, Debao Wen, Xing Peng, and Huaxiang Ding. "Continued Monitoring and Modeling of Xingfeng Solid Waste Landfill Settlement, China, Based on Multiplatform SAR Images." Remote Sensing 13, no. 16 (August 19, 2021): 3286. http://dx.doi.org/10.3390/rs13163286.
Повний текст джерелаАнотація:
Continued settlement monitoring and modeling of landfills are critical for land redevelopment and safety assurance. This paper adopts a MTInSAR technique for time-series monitoring of the Xingfeng landfill (XFL) settlement. A major challenge is that the frequent and significant settlement in the initial stage after the closure of landfills can affect the coherence of interferograms, thus hindering the monitoring of settlement by MTInSAR. We analyzed the factors that can directly affect the temporal decorrelation of landfills and adopted a 3D phase unwrapping approach to correct the phase unwrapping errors caused by such deformation gradient. SAR images from four platforms, including 50 Sentinel-1A, 12 Radarsat-2, 4 ALOS-2, and 2 TerraSAR-X/TanDEM-X images, are collected to measure the settlement and thickness of the landfill. The settlement accuracy is evaluated by a cross-evaluation between Radarsat-2 and Sentinel-1A that have similar temporal coverages. We analyzed the spatial characteristics of settlement and the relationship between the settlement and thickness. Further, we modeled the future settlement of the XFL with a hyperbolic function model. The results showed that the coherence in the initial stage after closure of the XFL is primarily affected by temporal decorrelation caused by considerable deformation gradient compared with spatial decorrelation. Settlement occurs primarily in the forward slope of the XFL, and the maximum line-of-sight (LOS) settlement rate reached 0.808 m/year from August 2018 to May 2020. The correlation between the settlement and thickness is 0.62, indicating an obvious relationship between the two. In addition, the settlement of younger areas is usually greater than that of older areas.
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Liu, Jin, Dong Wei Li, and Zhong Hui Xu. "Research on the Impact of Different VG on Electrokinetic Removal of Heavy Metal Wastes." Applied Mechanics and Materials 71-78 (July 2011): 1099–103. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.1099.
Повний текст джерелаАнотація:
This paper aims to investigate the effects of different VG (voltage gradient) on electrokinetic removal technology, and examine electrode pH, electric conductivity, voltage drop in the sample, electric current, and the electroosmotic flow. It is indicated that with the increase of VG, the electrolytic reaction rate accelerates during the electric removal experiment, which has affected both system current and the pH value & electric conductivity of electrolyte solutions. The higher VG is, the faster the electrolyte solution pH varies；the higher VG is, the faster the electric conductivity changes. Meanwhile the magnitude of electroosmotic flow increases with the increase of the VG.
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Mao, Dianhui, Zhihao Hao, Yalei Wang, and Shuting Fu. "A Novel Dynamic Dispatching Method for Bicycle-Sharing System." ISPRS International Journal of Geo-Information 8, no. 3 (February 28, 2019): 117. http://dx.doi.org/10.3390/ijgi8030117.
Повний текст джерелаАнотація:
With the rapid development of sharing bicycles, unreasonable dispatching methods are likely to cause a series of issues, such as resource waste and traffic congestion in the city. In this paper, a new dynamic scheduling method is proposed, named Tri-G, so as to solve the above problems. First of all, the whole visualization information of bike stations was built based on a Spatio-Temporal Graph (STG), then Gaussian Mixture Mode (GMM) was used to group individual stations into clusters according to their geographical locations and transition patterns, and the Gradient Boosting Regression Tree (GBRT) algorithm was adopted to predict the number of bikes inflow/outflow at each station in real time. This paper used New York’s bicycle commute data to build global STG visualization information to evaluate Tri-G. Finally, it is concluded that Tri-G is superior to the methods in control groups, which can be applied to various geographical scenarios. In addition, this paper also discovered some human mobility patterns as well as some rules, which are helpful for governments to improve urban planning.
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ABDULLAH, LAZIM, and HERRINI MOHD PAUZI. "AN EFFECTIVE MODEL FOR CARBON DIOXIDE EMISSIONS PREDICTION: COMPARISON OF ARTIFICIAL NEURAL NETWORKS LEARNING ALGORITHMS." International Journal of Computational Intelligence and Applications 13, no. 03 (September 2014): 1450014. http://dx.doi.org/10.1142/s146902681450014x.
Повний текст джерелаАнотація:
This paper intends to compare various learning algorithms available for training the multi-layer perceptron (MLP) type of artificial neural networks (ANNs). By using different learning algorithms, this study investigates the performances of gradient descent (GD) algorithm; Levenberg-Marquardt (LM) algorithm; and also Boyden, Fletcher, Goldfarb and Shannon (BFGS) algorithm to predict the emissions of carbon dioxide ( CO 2) in Malaysia. The impact factors of emissions, such as energy use; gross domestic product per capita; population density; combustible renewable and waste; also CO 2 intensity were employed in developing all ANN models investigated in this study. A wide variety of standard statistical performance evaluation measures were employed to evaluate the performances of various ANN models developed. The results obtained in this study indicate that the LM algorithm outperformed both BFGS and GD algorithms.
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Zhang, Chengyi, Wen Zhang, and Yuxin Wang. "Diffusion Dialysis for Acid Recovery from Acidic Waste Solutions: Anion Exchange Membranes and Technology Integration." Membranes 10, no. 8 (July 29, 2020): 169. http://dx.doi.org/10.3390/membranes10080169.
Повний текст джерелаАнотація:
Inorganic acids are commonly used in mining, metallurgical, metal-processing, and nuclear-fuel-reprocessing industries in various processes, such as leaching, etching, electroplating, and metal-refining. Large amounts of spent acidic liquids containing toxic metal ion complexes are produced during these operations, which pose a serious hazard to the living and non-living environment. Developing economic and eco-friendly regeneration approaches to recover acid and valuable metals from these industrial effluents has focused the interest of the research community. Diffusion dialysis (DD) using anion exchange membranes (AEMs) driven by an activity gradient is considered an effective technology with a low energy consumption and little environmental contamination. In addition, the properties of AEMs have an important effect on the DD process. Hence, this paper gives a critical review of the properties of AEMs, including their acid permeability, membrane stability, and acid selectivity during the DD process for acid recovery. Furthermore, the DD processes using AEMs integrated with various technologies, such as pressure, an electric field, or continuous operation are discussed to enhance its potential for industrial applications. Finally, some directions are provided for the further development of AEMs in DD for acid recovery from acidic waste solutions.
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Yan, Xiao Fei, Jian Han Lin, Rong Hui Wang, Mao Hua Wang, Dong An, and Yan Bin Li. "A High-Gradient Magnetic Separation System for Separating Magnetic Nanobeads from Aqueous Solution." Advanced Materials Research 505 (April 2012): 39–43. http://dx.doi.org/10.4028/www.scientific.net/amr.505.39.
Повний текст джерелаАнотація:
Magnetic separation is an emerging and promising technology in biological sample preparation. In this paper, a high-intensity and high-gradient magnetic separation system was developed to separate magnetic nanobeads from aqueous solution. This system mainly consisted of a magnetic separator, a micropump and an electronic timer. The magnetic separator was designed by placing two columns of permanent magnets in an aluminum holder. Two magnets in each column were laid out in repelling mode and a hole between the two columns was used to accommodate a 1.5 ml tube. Working with the electronic timer, the micropump was employed to remove waste solution at a certain rate after magnetic nanobeads captured onto the sides of the tube wall. The experiments for separation of magnetic nanobeads with diameters of 150 nm and 50 nm using the developed magnetic separation system were conducted to optimize the key parameters of the system including nanobeads concentration, separation time and flow rate. The separation efficiencies of magnetic nanobeads increased as the nanobeads concentration and the separation time increased, whereas decreased when the flow rate was increased. Experimental results proved that the proposed magnetic separation system was able to separate magnetic nanobeads (diameters of 150 nm and 50 nm) with separation efficiencies of 99% and 90% in 30 min and 150 min respectively.
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Ponizov, A. V., P. M. Vereshchagin, N. V. Chulkov, M. K. Sharaputa, and E. A. Baidariko. "Conditions, consequences and prevention ways of behind-the-casing flow in deep well injection disposal of liquid waste sites." Геоэкология. Инженерная геология. Гидрогеология. Геокриология, no. 2 (May 18, 2019): 56–67. http://dx.doi.org/10.31857/s0869-78092019256-67.
Повний текст джерелаАнотація:
The main detection methods, signs, geotechnical conditions, factors and potential consequences of liquid radioactive waste (LRW) behind-the-casing flow are described in the paper. Based on the modeling results for the real LRW components behind-the-casing flow, the mechanism of behind-the-casing flows evolution in the intervals of wells with increased permeability of cement stone are presented. The concentration of LRW components in these intervals changes significantly in time and depends not only on their current concentration in the waste and the permeability of the rock, but also on the pressure gradient, the direction and absolute value of which are determined by the well operation mode and natural hydrogeological conditions. It is noted that behind-the-casing flows of groundwater and LRW components are formed primary in injection wells, above its filter and top of aquifer used for LRW disposal (operational aquifer). The behind-the-casing flows lead to technogenic changes in the geological environment, which are local in space and time, and reduce the safety of such facilities as deep-level disposal sites for LRW (DDF LRW).
The vertical channel of increased permeability around injection wells and behind-the-casing flows may be prevented by improving the design and construction materials of wells, adjustment of the LRW disposal mode and other methods, including the use of new sealing materials and clarifying technical solutions.