Economical Solution Research Articles

Water-energy-food-land nexus challenges and contributions to the biofuel supply chain: Systematic review and meta-synthesis

The biofuel supply chain (BSC) management has received considerable attention in recent years for diversifying the energy matrix and the achievement of the Sustainable Development Goals (SDGs). However, despite the robust body of literature in studies addressing sustainable management and optimization, research integrating scarce resources in the production process still needs to be developed. Also, problems concerning the basic demands of water, energy, food, and land (WEFL) involve different levels of decision-making, multiple scales, and numerous stakeholders with different objectives. The synergistic management of these resources is called WEFL Nexus approach and constitutes one of the most complex sustainability challenges. Understanding the practical contributions of each dimension of the WEFL Nexus approach to biofuel supply chain management can make the concept more accessible to decision-makers and enable the formulation of practical and implementable programs. Based on this analysis, this article presents a systematic literature review and a meta-synthesis to highlight how the nexus approach contributes to the sustainable management of the biofuel supply chain. The results obtained in the research show that the WEFL Nexus approach can provide social and economic solutions for managing BSCs through the diversification of energy biomass sources, decontamination, use of wastewater, choosing the most appropriate locations for planting and installations according to geography, climate, and society, and meeting regional social demands for resources. Furthermore, this research shows that it is possible to optimize the use of resources while production flows are optimized.

Military Aviation and the Aviation Industry of the Russian Empire in the First World War: Potential, Economic and Technological Solutions (according to Archival Documents)

Military Aviation and the Aviation Industry of the Russian Empire in the First World War: Potential, Economic and Technological Solutions (according to Archival Documents)

Surface modification of TiO2 with a less expensive metal (iron) to exploit solar energy in photocatalysis: An ecological and economical solution

To degrade the tryptophan molecule through photocatalysis, the exploitation of solar energy in the present study necessitated the use of visible light active photocatalysts. Iron-transition metal nanoparticles were deposited on the surface of TiO2 powders through an impregnation method to obtain X%Fe-TiO2 for the purpose of improving the optical absorption of TiO2 in the visible light region. The effects of iron percentage (X%: 2,4 and 5), iron oxidation state and pH on the photocatalytic performance of TiO2 modified under solar irradiation were thoroughly studied. The characterization results by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM-EDS) indicate that iron nanoparticles were successfully fixed on the TiO2 surface. The absorption wavelengths of all X%Fe-TiO2 photocatalysts shifted towards the visible, confirming successful modification of the TiO2 surface with iron. Based on the empirical results, X%Fe-TiO2 nanomaterials demonstrate a higher activity compared with the unmodified TiO2 under solar irradiation. The 4%Fe(III)-TiO2 photocatalyst, in particular, displayed the highest photocatalytic activity at natural pH. The degradation was complete in 60 min. Therefore, it is interesting to note that iron had more functions and benefits than noble metals. The mechanism of the Fe-TiO2 system has been proposed in detail.

Rational structural solutions for triangular trusses

Wooden rafter structures have undoubted advantages, which determine their wide application. The object of the study is triangular rafter structures. The purpose of the research is to find the dependence of force values in the elements of the studied structure on the magnitude of its lifting boom. The calculation of a triangular truss using the Maxwell - Cremona diagram is presented. The efficiency of the proposed method was estimated on the basis of a study of the structure of a wooden truss of the “scissors” type. The following pattern has been established: the change in the coordinates of the points (abscissas) of the force diagram is inversely proportional to the change in f . It is determined the area of rational values of the lift (roof slope) at which the values of internal forces tend to a minimum. It was revealed that the values of force increments in the truss elements at each step increase from 27% to 2 times when the roof slope de-creases. Based on the graphical analysis of the obtained data the range of effective values of the roof slope at which the forces in the elements of the truss take minimum values was found. Using a graphic method of determining the forces, it is possible to check variants of the roof slope in the search for a rational solution of the “scissor” type truss structure. It follows that the proposed method contributes to the choice of the most economical structural solutions.

Geometric imperfection measurement on welded hybrid steel box‐section girders

AbstractHigh‐strength steel materials (steel grades of S500 ‐ S960) gaining prominence in civil engineering, especially for large‐span bridges. In the case of bridges, the application of hybrid girders combining low‐ and high‐strength steel materials is an effective and economical solution. The hybrid girders generally consist of webs comprised of low‐strength steel and flanges made of high‐strength steel. In Europe, apart from some minor practical applications and research results in Sweden, these structure types are completely new solutions in bridges, and the theoretical background of their stability design is missing from the current European standardized design provisions. To determine the theoretical background of this girder type and to develop the design theories for application purposes it is essential to execute experimental laboratory test programs. Analyzing the local buckling and plastic behavior of hybrid steel plate girders through experiments is essential to have an approopriate knowledge on the geometrical and structural imperfections of the hybrid girders. Therefore, in the present paper the measurement of geometric imperfection on 14 welded hybrid steel box‐section girders with varying geometry is presented and their results are evaluated and discussed. The flanges of the examined hybrid girders are made of S700 or S500, the web of the specimens consists of S355 steel grade. The measured imperfection values are evaluated based on the steel grade and geometric parameters such as plate width or thickness. Using the measured imperfection, a numerical model will be developed to predict the bending and shear resistance of the specimens.

Probabilistic economic evaluation of the most prevalent in Greek market space heating systems

In the present study, the most prevalent space heating (SH) systems are assessed by means of probabilistic economic method, for Athens (Greece) under the ongoing energy crisis. The examined SH systems are the air source heat pump, the natural gas boiler and the oil boiler. An apartment of 85 m2 living area is chosen as the standard Athenian dwelling type for the assessment of the SH systems. In addition, two economic scenarios are set related to the annual energy inflation rate, the pessimistic and the optimistic. Simulations are executed in TRNSYS for the physical system and in MATLAB for the economic analysis. The economic analysis is carried out with the combination of the Monte Carlo simulations and the Life Cycle Cost (LCC) method. It turned out that, the LCC (as net present value) for all systems is much higher than the pre-crisis cost and is not feasible under the existing obscure economic period. It was proved that, the energy cost subsidy may be a solution on the volatility of the energy market, however, this can be achieved with rather high subsidy rates. The air source heat pump system was found to obtain better economy than the conventional fuel-based systems and the pairing of the heat pump with the PV system proved as the only economic feasible solution. The developed methodology can be utilized for evaluating the investment risk associated with the uncertain of the future cost of energy.

Novel Hybrid Modular Construction System ‐ Structural Behaviour of Isolated Sub‐Frames

AbstractWith the rising necessity for sustainable, economic and fast construction solutions, reliable modular construction systems are increasingly in demand. This paper presents a novel lightweight modular construction system, consisting of tubular columns and light‐gauge cold‐form steel profiles, where the beam‐to‐column connection is established by an innovative plug‐and‐play joint. The experimental campaign conducted on the full‐scale isolated sub‐frame configurations is reported, together with the recorded specimen behavior. The experimental results are compared with the numerical FEM estimations, leading to conclusions regarding the system's global behavior, its potential and the influence of the novel joint.

Optimal Economic Dispatch and Power Generation for Microgrid Using Novel Lagrange Multipliers-Based Method With HIL Verification

Microgrid incorporating distributed renewable energy resources (RERs) is increasingly important owing to the goal to reach net-zero emissions by mid-century. This article deals with the optimal energy management of microgrid comprising RERs and battery energy storage system. In addition to considering power flow constraints and uncertainties of RERs, the importance of retaining profits of microgrid operators and the needs for providing extra supports to the main grid are rising. To meet all the requirements, a novel Lagrange multipliers-based method is proposed to deal with equality and inequality constraints simultaneously to directly obtain the optimal economic dispatch solution analytically. Moreover, a microgrid built in Cimei Island of Penghu Archipelago, Taiwan, is investigated to examine the compliance with the requirements of equality and inequality constraints and the performance of the Lagrange multipliers-based method. Furthermore, the comparison of the proposed method with experience-based energy management system, Newton-particle swarm optimization, and deep Q-learning network is provided to evaluate the obtained solutions. Finally, through the hardware in the loop mechanism, which is built using OPAL-RT real-time simulator with floating-point digital signal processor, the effectiveness of proposed Lagrange multipliers-based method is verified and proven to be pragmatic.

Large-Scale Indoor Localization Solution for Pervasive Smartphones Using Corrected Acoustic Signals and Data-Driven PDR

With continuous and accelerated urbanization, a large number of location-based services (LBS) have shifted from outdoor to indoor. The pervasive smartphone-based localization has been the subject of extensive work, including signals, algorithms, technologies, solutions, and applications. However, no single ubiquitous technology or solution exists for performing indoor positioning similar to the global navigation satellite system (GNSS) in the outdoor environment. The aim of this work is to develop a practical, precise, and economic smartphone-based localization solution. In order to address the challenges of utilizing the limited audible-band acoustic signal in pervasive smartphone localization, i.e., signal detection, correction, and evaluation, we present a low-cost anchor hardware, two-step signal detection method, data-driven pedestrian dead reckoning (PDR), and robust positioning algorithm. Moreover, we further propose acoustic measurement compensation approaches and measurement quality evaluation and control strategy (MQECS) to improve the performance of position estimation. Six phones, including Huawei Mate9, P9 Plus, OnePlus 6, Honor 8, Mi 10, and Google Pixel 3 are used to evaluate the localization performance in three typical wide area indoor scenarios (i.e., convention center, parking lot, and dining-hall). The total testbed area is accumulated to more than 8,800 square meters. The experimental results demonstrate that the proposed method achieves average positioning accuracies of 0.34 m (static) and 0.67 m (dynamic). In addition, the results show that the overall performance, repeatability, and stability are superior for different scenarios and devices.

Two-Stage Capacity Determination Framework for Residential Second-Life BESSs Considering Cloud Energy Storage Service

Second-life battery energy storage systems (SL-BESSs) have potential to be used as an economic and affordable energy storage solution for supporting a variety of applications, such as energy backup in residential sector. This article proposes a new capacity determination framework for SL-BESSs that are utilized in household environment. Despite the capital cost is significantly reduced, the degradation characteristics of retired batteries exhibits two-stage decline characteristics. The proposed framework first establishes the SL-BESSs model and estimates its remaining useful lifetime by identifying the “knee point” in the SL-BESSs capacity degradation curve; based on this, a two-level SL-BESS capacity determination model is formulated, which sizes the SL-BESS based on short-term home energy management under different scenarios. In particular, this article considers the dual-service modes of an SL-BESS in its capacity determination process: first, provide local energy supply to the household, and second, provide cloud energy storage service to external users. Extensive numerical simulations are conducted to validate the proposed framework.

An approach to utilize date seeds biochar as waste material for thermal energy storage applications

Rapid industrialization as a consequence of the green revolution and population proliferation has resulted in massive solid waste generation as well as greater energy consumption demands. With increasing energy demand coupled with ever-increasing waste generation, the time has come to think about global sustainability. The practice of green technology which is ecologically benevolent might be the foothold of waste management that renders resolutions. Therefore, waste valorization in sustainable energy forms can bring up an economic and suitable solution for the sustainability of civilization. Contemplating that, an attempt has been made to utilize date seeds as waste material for shape stabilization of phase change materials (PCMs) for effective thermal energy storage applications. Date seeds (DS) are ground to powder and pyrolyzed into porous biochar, having high porosity and channel-like morphology with a BET surface area of 187.07 m2/g. The PCM composites are accomplished by introducing capric acid (CA) into synthesized biochar (DSB). CA has been incorporated in 2:1 and 3:1 ratios into DSB and the thermal stability along with performance of the synthesized DSCA composites have been evaluated for their suitable applications. The 3:1 CA to DSB ratio has been realized as optimum for the highest accommodation of CA into DSB. Higher heat charging and discharging enthalpies of 72.4 and 71.76 J/g are accomplished for 1–3 DSCA sample as well as encapsulation efficiency and ratio are found to be 43.79 % and 43.96 %, respectively. During phase transitions, excellent leakage resistance and congruent heat charging and discharging capabilities have been manifested by the DSCA samples. The extraordinary performances displayed by the DSCA PCM composites are attributed to the surface tension, capillary action, space confinement and surface functionalities offered by the porous biochar.

Framework for choosing energy efficient mixing equipment whatever motions it induces: Example of application for planetary and helical ribbon mixers

Energy savings in industrial processes have become one of the main goals of the current society. This paper aims to propose a systematic approach for the assessment of mixing equipment energy performance for highly viscous fluids. The framework is illustrated and applied by performing a rational comparison of the homogenization efficiency of classical mixing systems (involving an agitator revolving around a vertical axis centred in the tank) with that of planetary mixers when mixing highly viscous fluids. For that purpose, the pioneering framework of Zlokarnik is first reminded and its limitations with regard to non-traditional mixing equipment are discussed. Then, the theoretical background to extend this approach to these latter is presented. Experimental data on power consumption and mixing time are provided to demonstrate the applicability of the present frame. The results illustrated that a planetary mixer can be an economic solution for performing highly viscous fluids homogenization.

Investigating the impact of thermal stresses on blistering effects in sandwich panels

AbstractLightweight steel constructions made of sandwich panels are an economical solution for wall and roof claddings, especially in industrial construction. The panels consist of two thin sheets of steel and a core with thermal insulating properties. In the mounted state and at high temperatures on the outer face of the panel, damage to the components may occur due to blister formation. In a current research project, the influence of defects in sandwich panels with a PIR‐foam core is examined. This article presents the results of experimental tests regarding the influence of various parameters, such as face temperature, production defects and design of the longitudinal joint on blistering in sandwich wall panels with a PIR‐core. The aim is to identify the necessary conditions for the occurrence of blisters. Using an optical strain measuring method (Digital Image Correlation), the temperature‐induced deformations and strains in the covering nose of sandwich wall panels with hidden fastening are measured and will be analyzed with regard to blistering. First results reveal a significant dependence on the geometry and design of the covering nose.

Hydropower Advantages over Batteries in Energy Storage of Off-Grid Systems: A Case Study

Microgrids are decentralized power production systems, where the energy production and consumption are very close to each other. Microgrids generally exploit renewable energy sources, encountering a problem of storage, as the power production from solar and wind is intermittent. This research presents a new integrated methodology and discusses a comparison of batteries and pumped storage hydropower (PSH) as energy storage systems with the integration of wind and solar PV energy sources, which are the major upcoming technologies in the renewable energy sector. We implemented the simulator and optimizer model (HOMER), which develops energy availability usage to obtain optimized renewable energy integration in the microgrid, showing its economic added value. Two scenarios are run with this model—one considers batteries as an energy storage technology and the other considers PSH—in order to obtain the best economic and technical results for the analyzed microgrid. The economic analysis showed a lower net present cost (NPC) and levelized cost of energy (LCOE) for the microgrid with PSH. The results showed that the microgrid with the storage of PSH was economical, with an NPC of 45.8 M€ and an LCOE of 0.379 €/kWh, in comparison with the scenario with batteries, which had an NPC of 95.2 M€ and an LCOE of 0.786 €/kWh. The role of storage was understood by differentiating the data into different seasons, using a Python model. Furthermore, a sensitivity analysis was conducted by varying the capital cost multiplier of solar PV and wind turbines to obtain the best optimal economic solutions.

The choice of optimal parameters of the retaining wall of the pit enclosure in conditions of dense construction, taking into account its spatial rigidity

The results of the study of the interaction of the pit enclosure made of flexible retaining walls, arranged in the conditions of dense construction, with the soil foundation are presented.
 Calculations were carried out by the method of numerical modeling, using the Plaxis software complex. The modeling is performed in a three-dimensional space, which provides an opportunity for a comprehensive assessment of the stress-strain state (SSS) of the elements of the system "soil array - retaining walls - structures of existing buildings" when using complex configurations of retaining walls and taking into account the factor of their spatial stiffness.
 For the analysis of the results, 4 characteristic sections were chosen. Modeling was performed taking into account the following stages:
 1) the initialization stage (formation of the soil massif in its natural state);
 2) installation of a retaining wall;
 3) alternate development of the pit to the design mark;
 4) load from the building at the stage of operation.
 Based on the results of the calculations, the SSS analysis of the elements of the system "soil massif - retaining walls - structures of existing buildings" was performed, and the reinforcement of the retaining walls was selected, and the costs of the main materials were determined.
 It is shown that taking into account the spatial stiffness of the retaining wall of the pit enclosure makes it possible to more effectively estimate the SSS of the retaining wall structure, more correctly estimate the additional deformations of neighboring buildings, due to taking into account the change in the stiffness of the retaining wall of a complex configuration, and therefore, in the future, to more effectively design the constructions of retaining walls.
 According to the results of the calculations, it is shown that retaining walls made in 2 rows in a staggered order, with piles with a diameter of 420 mm, have greater rigidity than retaining walls made in 1 row with piles with a diameter of 620 mm. Therefore, in order to reduce additional subsidence of neighboring buildings and reduce horizontal movements of the retaining wall, the option of the retaining wall made by placing piles in a staggered order is a priority in conditions of dense construction.
 Armature costs for option 1 are 46% higher compared to option 2. These results indicate that the 2nd option of installing a retaining wall is a more economical solution, however, in conditions of dense construction, its use is limited, since the settlement of neighboring buildings in this case will be greater, due to the lower rigidity of the retaining wall.

Towards a circular economy: fabrication and characterization of biodegradable plates from sugarcane waste

Bagasse pulp is a promising material to produce biodegradable plates. Bagasse is the fibrous residue that remains after sugarcane stalks are crushed to extract their juice. It is a renewable resource and is widely available in many countries, making it an attractive alternative to traditional plastic plates. Recent research has shown that biodegradable plates made from Bagasse pulp have several advantages over traditional plastic plates. For example, they are more environmentally friendly because they are made from renewable resources and can be composted after use. Additionally, they are safer for human health because they do not contain harmful chemicals that can leach into food. The production process for Bagasse pulp plates is also relatively simple and cost-effective. Bagasse is first collected and then processed to remove impurities and extract the pulp. The pulp is then molded into the desired shape and dried to form a sturdy plate. Overall, biodegradable plates made from Bagasse pulp are a promising alternative to traditional plastic plates. They are environmentally friendly, safe for human health, and cost-effective to produce. As such, they have the potential to play an important role in reducing plastic waste and promoting sustainable practices. Over the years, the world was not paying strict attention to the impact of rapid growth in plastic use. As a result, uncontrollable volumes of plastic garbage have been released into the environment. Half of all plastic garbage generated worldwide is made up of packaging materials. The purpose of this article is to offer an alternative by creating bioplastic goods that can be produced in various shapes and sizes across various sectors, including food packaging, single-use tableware, and crafts. Products made from bagasse help address the issue of plastic pollution. To find the optimum option for creating bagasse-based biodegradable dinnerware in Egypt and throughout the world, researchers tested various scenarios. The findings show that bagasse pulp may replace plastics in biodegradable packaging. As a result of this value-added utilization of natural fibers, less waste and less of it ends up in landfills. The practical significance of this study is to help advance low-carbon economic solutions and to produce secure bioplastic materials that can replace Styrofoam in tableware and food packaging production.

Self‐Closing and Self‐Healing Multi‐Material Suction Cups for Energy‐Efficient Vacuum Grippers

While vacuum grippers offer an economical solution, the environmental impact of energy waste through their suction cups (SCs) cannot be overlooked. This waste stems from three key factors: i) air losses from idle SCs arranged in arrays, ii) inadequate sealing on target surfaces leading to air leaks, and iii) damage from sharp objects resulting in leaking perforations. To overcome these challenges, in this article, a comprehensive approach is presented that involves the development of a i) self‐closing, ii) multi‐material, and iii) self‐healing system based on reversible elastomers cross‐linked via the Diels–Alder (DA) reaction. The system incorporates a fully autonomous self‐closing mechanism to prevent energy waste in SC arrays during periods of non‐contact. Fluid–structure interaction simulations are utilized to analyze the design. Versatility and stability are achieved by incorporating hyper‐flexible and stiff elastomers in a multi‐material design, supported by covalent DA cross‐links that ensure robustness through high‐strength multi‐material interfaces. These DA cross‐links also enable self‐healing capabilities, allowing the SCs to recover from macroscopic damages within 1 day at ambient conditions or in a single hour with mild heating (80–90 °C), restoring full performance. Additionally, in the article, a recycling method is introduced for multi‐material SCs based on the mechanical separation of reversible polymers.

A comparative assessment of open flame flares and enclosed ground flares for cleaner and safer hydrocarbon production in Mexico

Hydrocarbon industry flaring practices emit large amounts of unburned hydrocarbons and climate forcers, creating environmental and social impacts. The objective of this study is to thoroughly compare different flaring technologies in situations where the industry is unable to avoid flaring. An integrated methodology for assessing two flare technologies in terms of Health-Environment-Safety (HES) impacts, economic performance, and safety benefits is proposed. The methodology includes stoichiometric calculations of combustion reactions, pollutants emission estimation, flare dimensioning for an equivalent inflow stream to be flared, and economic scenarios for assessing Enclosed Ground Flares (EGFs) versus Open Flame Flares (OFFs). The methodology was applied to a Mexican hydrocarbon installation that currently operates OFFs with a historical record of low combustion efficiency. If an EGF were to replace the existing OFF, there would be a significant emissions abatement that depends on their realistic operating efficiencies. Furthermore, the EGF has the potential to utilize 1.55thermal GW for energy applications, which is currently being wasted as the OFF releases it into the environment by flaring 3.75 Mm3/d. The safety radius required for the OFF is 9.3 times that required for the EGF of equivalent capacity. Over a 30-year period for the case study, the cumulative investment and O&M costs for EGF are about 23% less than for OFF. The consequence analysis with the PHAST software found that various failure conditions can be contained within the EGF combustion chamber without causing significant damage to the facility. However, the impacts of disturbances in the OFF such as gas clouds, flash fires, and explosions are around the torch. All these findings indicate that replacing OFF with EGF would be a safer and more economical solution in the future, as it also helps reduce pollutant emissions.

Characterization of the Erosion Basin Shaped by the Jet Flow of Sky-Jump Spillways

The sky-jump spillway is an economical solution to return water to rivers, but an unsuitable flip bucket design might jeopardize the spillway, the dam, or other appurtenant works. Characterizing in advance, during the design phase, the position, size, and shape of the erosion basin would be useful to ensure that water flow is returned to the river in a safe way. Also, it would be useful for the safety assessment throughout the exploitation phase when erosion has not yet reached its maximum extension. Here, based on experimental laboratory work, the location, size, and shape of the erosion basin are analyzed, and a procedure is given for its characterization according to the design of the sky-jump spillway.

Progress in recycling and reutilization of waste polyethylene terephthalate

Polyethylene terephthalate (PET) is a versatile material with a wide range of applications, and the demand for PET products has been steadily increasing in recent years. This has generated large quantities of non-biodegradable PET waste. To reduce environmental pollution, recycling and reuse of waste PET is an economical solution. Different PET products vary greatly in their impurity contents, processing technology, and performance, which poses certain challenges for the recovery, purification, and reuse of PET waste in a high value-added manner. Various recycling and reutilization methods are compared, potential issues with different PET products in the recycling process are analyzed, and viscosity enhancement modification techniques and applications of recycled PET are introduced. This paper provides a reference for the recycling of various waste PET products.