On the fatigue behaviour of quenched and tempered at 300 and 600 °C SAE 1045 steel in an environment of sugar cane juice

SAE 1045 steel is widely used for manufacturing shafts in the sugar cane mills of the sugar industry. These shafts are designed with an expectation of a long lifetime. However, fatigue failures occur frequently. The sugar cane juice processed in these mills has corrosive properties that can alter the fatigue life of these shafts. In this research, the fatigue strength of SAE 1045 steel between 1 × 10⁴ and 2 × 10⁵ cycles in air and in sugar cane juice, with two different microstructures (tempered martensite at 300 °C and tempered martensite at 600 °C), was determined in rotating bending. The microstructure of the materials was characterized using optical microscopy, and the fracture surfaces were characterized using scanning electron microscopy. The results show that the fatigue strength at 2 × 10⁵ cycles for the tempered condition at 600 °C decreases 7% because of the sugar cane juice effect, and for the tempered condition at 300 °C, the fatigue strength decreases 15%.     

Sugar Cane Bagasse Waste as Reinforcement in Low Cost Composites

The State University of the North of Rio de Janeiro State is currently engaged on a large development program to exploit the potentialities of sugar cane industry in a self sustained nonpolluting program. Sugar cane is a traditional industry responsible for the main fraction of the economy of the northern region of the State of Rio de Janeiro, also known as the North Fluminense region. In this respect, a project of particular interest is the use of the sugar cane bagasse waste as reinforcement to polymeric resins for fabrication of low cost composites. In the present work a study was carried out on the possible uses of bagasse waste as reinforcement in polyester matrix composites. Preliminary results have attested this possibility. Composites with homogeneous microstructures could be fabricated and the level of their mechanical properties enable them to have practical applications similar to the ones normally associated with wooden agglomerates. Future developments are expected to increase the performance and competitiveness of these composites as compared to those of other materials in the same structural class.     

甘蔗渣对聚甲基丙烯酸甲酯热降解的影响

目的分析生物质材料对塑料废弃物热降解的影响,以聚甲基丙烯酸甲酯(PMMA)为对象,探讨甘蔗渣对其热分解行为和动力学的作用。方法利用溶液共混法制备PMMA/甘蔗渣混合物,采用热失重法研究其在氮气中的热分解过程,通过最大失重速率法和Ozawa等失重法计算PMMA热分解反应的动力学参数活化能和频率因子。结果甘蔗渣使得PMMA的初期热分解温度明显降低,但是PMMA的热分解活化能和频率因子却都显著增加。最大失重速率法的计算结果表明,PMMA加入甘蔗渣后的热分解活化能增加了26.2 k J/mol,等失重法的结果显示活化能和频率因子分别为168.14 k J/mol和28.41 min-1,比纯PMMA相应地增大了72.6 k J/mol和12.52 min-1。结论甘蔗渣的加入对PMMA的热降解有显著的影响,使其热分解变得困难,因此有必要进一步探讨其他生物质对PMMA热分解的影响。     

鲜切山药保鲜护色研究

目的利用家用调味剂(蔗糖、食盐、白醋)对鲜切山药保鲜护色进行研究。方法利用L9(34)正交试验配置一定浓度的蔗糖、食盐、食醋复合浸渍液,并用聚乙烯薄膜进行包装,得出比较理想的鲜切山药贮藏方法。结果蔗糖、食盐、白醋都有很好的保鲜护色效果,单因素试验表明,当采用蔗糖、食盐、食醋(质量浓度分别为3,1,3 g/L)浸泡鲜切山药10 min后,其褐变度的减缓和PPO活性的抑制最为明显。正交试验结果表明,采用蔗糖、食盐、白醋质量浓度分别为4,2,3 g/L混合处理液浸泡10 min后,护色保鲜效果最好。结论经过特定浓度复配的蔗糖、食盐、白醋溶液能有效抑制鲜切山药的酶促褐变,起到保鲜护色的作用。     

Effects of calcining conditions on the microstructure of sugar cane waste ashes (SCWA): Influence in the pozzolanic activation

In this paper a study of calcining conditions on the microstructural features of sugar cane waste ash (SCWA) is carried out. For this purpose, some microparticles (<90 μm) of sugar cane straw ash and sugar cane bagasse ash of samples calcined at 800 °C and 1000 are studied by combining the bright field and the dark field images with the electron diffraction patterns in the transmission electron microscopy (TEM). It is appreciated that the morphology and texture of these microparticles change when silicon or calcium are present. Furthermore, it is observed that iron oxide (magnetite Fe₃O₄) is located in the calcium-rich particles.The microstructural information is correlated with the results of a kinetic–diffusive model that allows the computing of the kinetic parameters of the pozzolanic reaction (mainly the reaction rate constant). The results show that the sugar cane wastes ash calcined at 800 and 1000 °C have properties indicative of high pozzolanic activity. The X-ray diffraction patterns, the TEM images and the pozzolanic activity tests show the influence of different factors on the activation of these ashes.     

Failure detection and optimization of sugar mill boiler using FMEA and Taguchi method

Sugar industry plays an important role in economic development of country. Cogeneration is an important source of income for sugar industries. Boiler is one of the essential components used in cogeneration process. Unscheduled boiler outages in sugar mills are major problem resulting loss of production. The boiler may be failed due to number of reasons; some of the reasons such as mechanical failure, electrical failure and temperature sensors failure. This paper describes the failures of the fuel feeding system frequently occurred in the cogeneration boiler and gives the solution to rectify these failures by using three important tools, namely, cause and effect diagram, Failure Mode and Effect Analysis and Taguchi method.     

Application of cleaner technologies in milk processing industry to improve the environmental efficiency

Changes in production processes and products that result in improvement of environmental, economic and social performance of enterprises are an important element of the overall process towards more sustainable production. The aim of this article is to demonstrate the application of cleaner production and eco-design as sustainable production tools to improve the environmental efficiency of milk processing industry. Milk processing industry is one of the largest and dynamically developing branches of industry in the world. The main impact of milk processing industry on the environment is related to energy and water consumption, and waste and wastewater generation. A number of potential solutions to improve the environmental performance of milk processing industry, to reduce energy and resources consumption are analysed: substitution of cleaning agent in the milk receiving bar for washing of milk tankers with the specialised acidic detergent, integration of the automated CIP washing system in the butter bar, implementation of water recycling system to collect warm (35?°C) water, integration of the membrane technologies for the evaporation process and the use of filtrate received during the condensation for steam generation in the boiler house. Finally, an eco-design solution for cans of milk products is presented. All these proposals have been implemented in the milk processing company.     

Environmental study of producing microalgal biomass and bioremediation of cattle manure effluents by microalgae cultivation

This study conducts a Life Cycle Assessment (LCA) of microalgae grown in laboratory scale using different mediums to produce biomass and purify the effluent organic load. Within this LCA, two microalgae cultivation systems were evaluated: (1) cultivation with synthetic nutrients (CSN) and (2) cultivation with cattle manure effluent from biodigestion (CME). The comparison unit among the two culture systems was the production of 10 g of dry microalgae Scenedesmus sp. biomass through the CML 2000 method. Environmental aspects and impacts of the two systems were analyzed, showing that the CME required less water and reduced the potential for eutrophication in comparison with the CSN. Furthermore, the CME reduced all physical–chemical parameters indicating efficient purification of the effluent through microalgae cultivation, resulting in a 92.5% decrease in total nitrogen and a 51.9% decrease in phosphorus. The key conclusions were that CME is an environmentally conscious and promising technology for wastewater treatment when combined with microalgae biomass production. Although the analysis was conducted in laboratory scale, it is reasonable to project the results to a larger-scale production, provided that adequate control strategies are implemented. Follow-up studies should be conducted with microalgae cultivated in similar effluents to cattle manure (e.g., pig or chicken manure, sugar cane industry effluents and wastewater) in order to evaluate their potential for biomass production and wastewater treatment applications.     

Fermentative lactic acid production from a renewable carbon source under response surface optimized conditions without alkali addition: a membrane-based green approach

Experimental investigations were carried out on production of lactic acid from sugar cane juice by Lactobacillus delbruckii in a membrane-integrated and non-neutralizing fermentation system after an initial optimization study. As the process produced lactic acid directly instead of through lactate salt as in traditional processes, many intermediate steps could be bypassed. Most relevant operating parameters like temperature, concentrations of yeast extract, and peptone were optimized first through rigorous experimentation following response surface methodology. At 41°C, 116.28?g?l^?1 lactic acid concentrations was reached with 13.82?g?l^?1 yeast extract and 7.69?g?l^?1 peptone concentration. However, higher yield (96%) was obtained with diluted sugarcane juice containing 102.20?g?l^?1 sucrose. The most remarkable achievement of this new design is that it can produce lactic acid with high degree of purification directly from a renewable and cheap carbon source in an eco-friendly process representing high process intensification.     

Citric acid separation using a hollow fibre liquid membrane system

Citric acid is the bulk chemical produced in the largest volume by fermentation using Aspergillus niger in submerged cultures. It can be made from sugar cane juice, or cane or beef molasses, and acid concentrations up to around 15% can be achieved.     

Comparing the pozzolanic behavior of sugar cane bagasse ash to amorphous and crystalline SiO2

The present paper aims to clarify the pozzolanic behavior of sugar cane bagasse ash-SCBA by comparing it to amorphous and crystalline silica. It is shown that calcium silicate hydrate is formed in lime solution with SCBA but the reaction is slow and does not consume all the material. Comparing its results with the obtained in tests with silica fume and with crushed quartz show a better agreement with the latter. Characterization of cement pastes shows 20% of cement replacement by sugar cane bagasse ash leads to only a minor reduction in the amount of calcium hydroxide formed. This behavior is also closer to the observed in quartz than in silica fume. The results suggest SCBA should be used as a replacement for inert constituents in cement composites rather than pozzolanic addition. Analysis of the microstructure of the cement pastes revealed the presence of calcium hydroxide in samples prepared with partial replacement by silica fume, quartz and sugar cane bagasse ash. The presence of this phase in the sample prepared with silica fume was attributed to agglomeration of the particles that affected the reactivity of this material.     

Biofuel Production: Utilizing Stakeholders’ Perspectives

Abstract

The use of biofuels as a replacement for fossil fuels is growing in the United States and other countries in part because of economic and environmental concerns. One of the technologies for biofuels production is fast pyrolysis; however, to increase manufacturing of fast pyrolysis units, a better understanding of stakeholders’ requirements and perspectives is needed. This is a complex decision problem. Due to the diversity of perspectives, each group of stakeholders has their own unique requirements, which in total will determine the right manufacturing approach. Previous studies either investigated optimal sizing from a single viewpoint or have combined a subset of perspectives. This study applies multiple tools to develop a more comprehensive view of stakeholders’ perspectives. Individual subject matter experts were asked to review and prioritize a set of requirements that reflected different stakeholders’ perspectives, including economic, environmental, technical, social, and legal. The perspectives were then used to analyze multiple fast pyrolysis units to determine which size was the most effective in meeting the perspectives in total. The analysis indicated that the smallest unit, able to process an average of 50 tons per day, is the best alternative when viewed from the economic, technical, social, and legal perspectives. However, when viewed from the environmental perspective, a medium-sized unit, able to process in the range of 200–500 tons per day, is the best alternative. This work provides the basis for further discussions about the individual perspectives, including the economic and environmental perspectives of biofuel production. Potential avenues for further work in assessment of stakeholders’ requirements are also noted.     

Optimization of condition-based maintenance considering partial opportunities

Recent studies have demonstrated the economic benefit of exploiting partial opportunities for maintenance, which arise from the reduction of costs of doing partial maintenance utilizing the opportunity given. A typical example is an externally induced production stop with a duration that may not be sufficient to a complete maintenance activity. This paper combines partial opportunities and condition-based maintenance (CBM) strategies and proposes an innovative maintenance optimization method considering time-varying economic conditions. This scenario naturally fits a broad range of assets with a finite design life (including long-life machinery and infrastructure), operating under variable economic conditions and usage-intensities. The maintenance optimization problem is formulated in this study as a finite-horizon Markov decision process, where the randomly occurring opportunities are accounted for by augmenting the time-varying, decision-dependent transition probabilities. A dynamic programming approach is subsequently used to obtain the optimal CBM policy, consisting of time-varying thresholds on equipment condition and the cost of conducting maintenance during the arrived opportunity. A case study of such a maintenance policy for an induced draft fan of a sugar production system located in Queensland, Australia, is undertaken to evaluate the benefits of the proposed methodology against more traditional approaches that neglect opportunities or consider only replete opportunity durations.     

Economic design of exponential charts for time between events monitoring

The occurrence of defects or non-conformities in manufacturing processes can usually be modeled by a homogeneous Poisson process. However, the process parameter may change over time and it can be monitored with statistical process control techniques. Control charts based on an exponential distribution, called exponential charts in this paper, can be developed to monitor the occurrence rate of such events. For manufacturers, the economic objective of production is very important and has to be optimized. An economic approach is developed in this paper for the design of exponential charts. We compare and contrast the performances of statistical design, economic design and economic–statistical design. The usefulness of the proposed economic design approach is justified. The relationships among these designs are illustrated through numerical examples. In particular, the economic–statistical design approach is interpreted from a multi-objective optimization viewpoint. The limitations of the approach as well as future research are also discussed.     

Using integrated process and microeconomic analyses to enable effective environmental policy for shale gas in the USA

As one of the largest consumers of energy and emitters of greenhouse gases in the world, the USA must balance energy demand and security with environmental responsibility. Recently, shale gas has emerged as a promising element toward a solution to this dilemma. Currently, shale gas production is regulated under the same rules that govern traditional oil and gas operations, without consideration for the unique environmental challenges associated with the unconventional gas extraction process. It involves small independent operators that typically utilize the most cost-effective extraction processes without necessarily prioritizing the environmental impact of their operations. As a result, opposition to shale gas extraction threatens the continuity and sustainability of the shale gas industry. The negative externalities and information asymmetry associated with this market continue to be captured in a price of natural gas which is not inclusive of the environmental costs of the extraction processes. The objective of this work is to determine the environmental policies that will lead to sustainable shale gas production. A hierarchical approach is developed to benchmark current technologies and to generate, assess and select technologies and policies that overcome market hurdles while addressing EHSS objectives. The approach analyzes the technical and microeconomic impacts of environmental remediation techniques and then takes a multipronged policy approach which supports the microeconomic, environmental, health and safety goals. To illustrate the usefulness of the proposed approach, a case study is solved for the Barnett Shale play to assess at the microeconomic and environmental implications of environmental remediation technologies for shale gas operations. Based on the results of the analysis, technology changes create both economic and environmental benefits for operators indicating a market failure resulting in the priceless favorable technologies do not reflect their impact on the environment. The market failures in the process are analyzed and four policy alternatives to the status quo are evaluated against four policy goals. The primary recommendation resulting from the analysis, the Comprehensive policy alternative, uses a phased approach to drive ongoing innovation in the shale gas industry, stimulate demand for natural gas and reduce the information asymmetry. The implementation of this policy is then applied to an economic and environmental model of a cluster of wells in the Barnett Shale to determine how the policy would be implemented.     

Numerical simulation of dam construction using low-CO<Subscript>2</Subscript>-emission concrete

Cement production gives rise to CO₂ emissions generated by the calcination of CaCO₃ and by the combustion of fossil fuels, being responsible for about 5% of the global CO₂ emissions. These emissions can be substantially reduced if cement replacement materials are used. In this paper two residual ashes that can be used as mineral additions are considered: sugar cane bagasse ash and rice husk ash. A case study of the construction of a dam with a blended material composed by cement and these two ashes is presented, indicating the potentiality of its use for civil engineering applications. The analyses were performed using experimental and numerical tools developed on the basis of a thermo-chemo-mechanical model. This model considers the coupling, within the theory of thermodynamics, of the several phenomena that intervene in the hydration process, namely, exothermicity, thermo-activation, chemo-plasticity, evolution of thermal and mechanical properties with the hydration reaction, which includes creep and relaxation.     

Smart Contract to Traceability of Food Social Selling

Traditionally, food sustainability has been considered solely in the stage of agricultural production. However, globalization, the expansion of the food production industry, and the emergence of supermarket chains that control the retail food market require specific significant changes in supply chains in the food sector and, therefore, we need to address the economic, social, and environmental impacts of these events. On the other hand, social selling has increased rapidly in recent years, with a further boom, following current events related to the coronavirus disease (COVID-19). This explosion of social sales, where there are usually no control and regulation entities, can bring problems associated with mishandling items. In this paper, we expose how Blockchain technology supports the traceability of social sales by validating the data provided by the chain participants such as digital health passports, production and transport data in the sale process; the proposed solution generates recommendations on product management considering the agreements previously made by the network actors. To evaluate the proposed smart contracts, we use Hyperledger Caliper, obtaining an average throughput of 12.6 transactions per second and an average latency of 0.3 s for the asset update process. We also use a study case to evaluate the proposed project platform’s selling-transport stage using Internet of Things (IoT) sensors.     

Estimating the economic cost of emission reduction in Chinese vehicle industry based on multi-objective programing

By enforcing emission reduction policies, the economic effects on different industry are quite diverse. Scientific estimation for this kind of effect has important realistic meaning for the industry development. A multi-objective programing approach integrated with input–output analysis model is used in this paper to evaluate the impact of emission reduction policy on the cost of reducing gas emissions and undertaking industrial adjustment in Chinese vehicle industry. The empirical results show that gas emission control has positive influence on vehicle industry production value. But, this influence is lower than the average macro-economic cost of CO₂ emission in China. These policy implications on vehicle industry are less serious than other high emission industries and, at the same time, the enforcement of reduction policy is a chance for new energy vehicle development.     

Structural and thermal characterization of Moroccan sugar cane bagasse cellulose fibers and their applications as a reinforcing agent in low density polyethylene

Cellulose fibers were isolated from Moroccan sugar cane bagasse by using three distinct stages. Firstly bagasse was subjected to (1) a hot water (70 °C) treatment to eliminate hemicellulose, then to (2) an alkaline aqueous solution (15% of sodium hydroxide (NaOH), 98 °C) treatment to eliminate lignin, and finally to (3) a bleaching stage. Sugar cane bagasse cellulose fibers were analyzed by different complementary analysis (FT-IR; ¹³C NMR and TG). The reinforcing capability of cellulose fibers extracted from sugar cane bagasse was investigated using low density polyethylene as matrix. The cellulosic preparations were free of bound lignin. The intrinsic viscosity, the viscosity average and the molecular weight were respectively 511 ml/g, 1769 and 286578 g/mol. An enhance on mechanical properties of composites was found, a gain of 72% in Young’s modulus at 25 wt.% fiber loading and a gain of 85% in flexural modulus at 25 wt.% fiber loading, as a results of a good interface adhesion between cellulose fibers and matrix.     

Establishment of process parameters for producing Al-foam by dissolution and powder sintering method

Al-foams have been manufactured by a dissolution and powder sintering process using crystalline raw cane sugar, as a novel leachable pattern. The method involves mixing and compaction, leaching and sintering processes. The influence of the process parameters on the microstructure of the produced foam is investigated in order to optimize the process conditions and produce high quality Al-foams. The differences between the actual and calculated porosity of the produced foam is ascribed to the joint effect of the retained porosity of the green product and the shrinkage during sintering. The optimum ranges of compaction pressure and sintering temperature are 250–300 MPa and 680–750 °C respectively.