Modelling the Heating Process in the Transient and Steady State of an In Situ Tape-Laying Machine Head

As the use of composite materials increases, the search for suitable automated processes gains relevance for guaranteeing production quality by ensuring the uniformity of the process, minimizing the amount of scrap generated, and reducing the time and energy consumption. Limitations on production by traditional means such as hand lay-up, vacuum bagging, and in-autoclave methods tend not to be as efficient when the size and shape complexity of the part being produced increases, motivating the search for alternative processes such as automated tape laying (ATL). This work aims to describe the process of modelling and simulating a composite ATL with in situ consolidation by characterizing the machine elements and using the finite differences method in conjunction with energy balances in order to create a digital twin of the process for further control design. The modelling approach implemented is able to follow the process dynamics when changes are made to the heating element and to predict the composite material temperature response, making it suitable for use as a digital twin of a production process using an ATL machine.

Panel evidence from rural Uganda on mobile money, risk sharing, and educational investment

We investigate the influence of the rapidly developing mobile banking service "mobile money" on rural households' capacity to smooth their investment in education following a negative shock. We find that a negative shock reduces per school-age kid educational spending by 9.3 percentage points in families that do not utilize mobile money but by 8.3 percentage points in homes that have used mobile money. The underlying process is a rise in remittance receipts and sender variety as a result of the lower transaction costs afforded by mobile money. We demonstrate that our findings are resistant to alternative processes. We utilize the extension of the mobile money agent network as an exogenous variable in mobile money access.

Catalytic Amidomethylative [2+2+2] Cycloaddition of Formaldimine and Styrenes toward N-heterocycles

Chemo-switchable catalytic [2+2+2] cycloaddition of alkenes with formaldimines has been reported. Bis(tosylamido)methane (BTM) and 1,2-ditosyl-1,2-diazetidine (DTD), two bench-stable precursors for highly reactive tosylformaldimine, have been identified to be effective. BTM worked as a selective releaser of the formaldimine for catalytic [2+2+2] reactions toward hexahydropyrimidine products via a presumable “imine-alkene-imine” addition. A unique catalytic retro-[2+2] reaction of DTD was used and has enabled a proposed “imine-alkene-alkene” pathway with high chemoselectivity for the synthesis of 2,4-diarylpyperidine derivatives. The two alternative processes were catalyzed by simple and environmentally benign catalysts InCl3 and FeBr2, respectively.

Modelling the Heating Process at Transient and Steady State of an In Situ Tape Laying Machine Head

As use of composite materials increases, the search for suitable automated processes gains relevance to guarantee production quality by ensuring uniformity of the process, minimizing the amount of generated scrap and reducing time and energy consumption. Limitations on production by traditional means such as hand lay-up, vacuum bagging and in-autoclave methods, tend not to be as efficient when the size and shape complexity of the part being produced increases, motivating the search for alternative processes such as the Automated Tape Laying (ATL). This work aims to describe the process of modelling and simulating a composite ATL with in situ consolidation by characterizing the machine elements, using the finite differences method in conjunction with energy balances, in order to create a digital twin of the process for further control design. The modelling approach implemented is able to follow the process dynamics when changes to the heating element are imposed as well as to predict the composite material temperature response, making it suitable to work as a digital twin of a production process using an ATL machine.

Avoiding the Production of Polluting and Toxic Chemicals in the Tanning Process

Polluting and potentially toxic chemicals are used in tanning. Sodium sulfide/hydrosulfide are used when the hides are unhaired. These chemicals can be transformed into hydrogen sulfide with a simple change of pH. This gas is highly toxic and is the recurring cause of many deaths and accidents due to suffocation of workers in tanneries around the world. The basic salts of chromium III are the most used chemical to tan. The chromium III used can be transformed by oxidation, even once the leather transformed into a consumer good (shoes, for example), in chromium VI, which is carcinogenic. Both chemicals are present in process floats, in residual floats and in solid waste generated. Chromium III is also present in manufactured leathers. This article aims to describe the problems associated with the use of the aforementioned hazardous materials and deepen the possibility of using less toxic alternative processes to tan. The designed process allows to significantly reduce the pollutant load of the discharged wastewater, facilitates the reuse of the solid waste generated and clearly improve the safety of people at work.

Modelling the Heating Process at Transient and Steady State of an In Situ Tape Laying Machine Head

As use of composite materials increases, the search for suitable automated processes gains relevance to guarantee production quality by ensuring uniformity of the process, minimizing the amount of generated scrap and reducing time and energy consumption. Limitations on production by traditional means such as hand lay-up, vacuum bagging and in-autoclave methods, tend not to be as efficient when the size and shape complexity of the part being produced increases, motivating the search for alternative processes such as the Automated Tape Laying (ATL). This work aims to describe the process of modelling and simulating a composite ATL with in situ consolidation by characterizing the machine elements, using the finite differences method in conjunction with energy balances, in order to create a digital twin of the process for further control design. The modelling approach implemented is able to follow the process dynamics when changes to the heating element are imposed as well as to predict the composite material temperature response, making it suitable to work as a digital twin of a production process using an ATL machine.

Performance of Alternative Methane Reforms Based on Experimental Kinetic Evaluation and Simulation in a Fixed Bed Reactor

A comparative evaluation of alternative methane reforming processes as an option to steam reforming was performed by carrying out simulations of operations in a fixed bed reactor with a Ni (4.8 wt.%/γ-Al2O3) catalyst at 1023 K under 1.0 bar. Methane reforms, including processing with carbon dioxide (DRM, CH4/CO2), autothermal reform (ATRM, CH4/H2O/O2), and combined reform (CRM, CH4/CO2/H2O/O2) had their operations predicted based on experimental data developed to represent their kinetic behavior, formalized with mechanisms and parametric quantifications. The performance of fixed bed reactor operations for methane conversions occurred with different reaction rates in the three alternative processes, and comparatively the orders of magnitude were 102, 10−1, and 10−4 in CRM, ATRM, and DRM, respectively. According to each process, the methane conversions were oriented towards the predominant productions of hydrogen or carbon monoxide, indicating the kinetic selectivities of H2, 86.1% and CO, 59.2% in CRM and DRM, respectively. Considering the possibility of catalyst deactivation by carbon deposition, its predicted yields are low due to the slow stages of its production and due to its simultaneous consumption through interactions with O2, CO2, and H2O, reflecting favorably in additional productions of H2 and CO.

Carob Pulp: A Nutritional and Functional By-Product Worldwide Spread in the Formulation of Different Food Products and Beverages. A Review

Carob (Ceratonia siliqua L.) pod is a characteristic fruit from the Mediterranean regions. It is composed by seeds, the valuable part due to the extraction of locust bean gum, and the pulp, considered a by-product of the fruit processing industry. Carob pulp is a mixture of macro- and micronutrients, such as carbohydrates, vitamins and minerals, and secondary metabolites with functional properties. In the last few years, numerous studies on the chemical and biological characteristics of the pulp have been performed to encourage its commercial use. Its potential applications as a nutraceutical ingredient in many recipes for food and beverage elaborations have been extensively evaluated. Another aspect highlighted in this work is the use of alternative processes or conditions to mitigate furanic production, recognized for its toxicity. Furthermore, carob pulp’s similar sensorial, chemical and biological properties to cocoa, the absence of the stimulating alkaloids theobromine and caffeine, as well as its low-fat content, make it a healthier potential substitute for cocoa. This paper reviews the nutritional and functional values of carob pulp-based products in order to provide information on the proclaimed health-promoting properties of this interesting by-product.

Application of Plastic Wastes in Construction Materials: A Review Using the Concept of Life-Cycle Assessment in the Context of Recent Research for Future Perspectives

The urbanization process contributes to the growth of solid waste generation and causes an increase in environmental impacts and failures in the management of solid waste. The number of dumps is a concern due to the limited implementation and safe disposal of this waste. The interest in sustainable techniques has been growing in relation to waste management, which is largely absorbed by the civil construction sector. This work aimed to review plastic waste, especially polyethylene terephthalate (PET), that can be incorporated with construction materials, such as concrete, mortars, asphalt mixtures, and paving. The use of life-cycle assessment (LCA) is related, as a tool that allows the sustainability of products and processes to be enhanced in the long term. After analyzing the recent literature, it was identified that studies related to plastic wastes in construction materials concentrate sustainability around the alternative destination of waste. Since the plastic waste from different production chains are obtained, it was possible to affirm the need for a broader assessment, such as the LCA, providing greater quantification of data making the alternative processes and products more sustainable. The study contributes to enhance sustainability in alternative building materials through LCA.