Motivated by the fact that both security and energy efficiency are the fundamental requirements and design targets of future satellite communications, this letter investigates secure energy efficient ...beamforming in multibeam satellite systems, where the satellite user in each beam is surrounded by an eavesdropper attempting to intercept the confidential information. To simultaneously improve the transmission security and reduce power consumption, our design objective is to maximize the system secrecy energy efficiency (SEE) under the constraint of total transmit power budget. Different from the existing schemes with high complexity, we propose an alternating optimization scheme to address the SEE problem by decomposing the original nonconvex problem into subproblems. Specifically, we first utilize the signal-to-leakage-plus-noise ratio metric to obtain closed-form normalized beamforming weight vectors, while the successive convex approximation method is used to efficiently solve the power allocation subproblem. Then, an iterative algorithm is proposed to obtain the suboptimal solutions. Finally, simulations are provided to verify the superiority of the proposed scheme compared to the benchmark schemes.
The use of mixed matrix membranes (MMMs) comprising metal–organic frameworks (MOFs) for the separation of COsub.2 from flue gas has gained recognition as an effective strategy for enhancing gas ...separation efficiency. When incorporating porous materials like MOFs into a polymeric matrix to create MMMs, the combined characteristics of each constituent typically manifest. Nevertheless, the inadequate dispersion of an inorganic MOF filler within an organic polymer matrix can compromise the compatibility between the filler and matrix. In this context, the aspiration is to develop an MMM that not only exhibits optimal interfacial compatibility between the polymer and filler but also delivers superior gas separation performance, specifically in the efficient extraction of COsub.2 from flue gas. In this study, we introduce a modification technique involving the grafting of poly(ethylene glycol) diglycidyl ether (PEGDE) onto a UiO-66-NHsub.2 MOF filler (referred to as PEG-MOF), aimed at enhancing its compatibility with the 6FDA-durene matrix. Moreover, the inherent COsub.2-philic nature of PEGDE is anticipated to enhance the selectivity of COsub.2 over Nsub.2 and CHsub.4. The resultant MMM, incorporating 10 wt% of PEG-MOF loading, exhibits a COsub.2 permeability of 1671.00 Barrer and a COsub.2/CHsub.4 selectivity of 22.40. Notably, these values surpass the upper bound reported by Robeson in 2008.
It is significant to evaluate accurately energy efficiency of ethylene cracking furnace as the highest energy consumption device in ethylene production. However, previous energy efficiency evaluation ...methods mainly concentrate on system-level evaluation of ethylene production and fail to consider effects of production load on operation conditions, which are unsuitable for detailed evaluation online. Considering single energy efficiency content and impractical improvement scheme of DEA and unreasonable static baselines in TOPSIS, a modified TOPSIS energy efficiency evaluation method is proposed. A set of new energy efficiency indicators is designed through matter conversion and energy transformation together with matter and energy interaction. To acquire real-time energy efficiency a simulation model of cracking furnace is established by employing radial basis function neural network. To improve evaluation accuracy, the relations among energy efficiency and operation conditions and production load are quantified by calculation formulas of energy efficiency indicators and functions extracted from simulation model. The sequential quadratic programming algorithm is suggested to solve dynamic baselines according to real-time production load by adjusting operation conditions within constraints. Furthermore, optimal operation conditions are provided by searching for maximum comprehensive energy efficiency. Finally, validity of proposed evaluation method is illustrated by applying in a practical cracking furnace.
•A revised TOPSIS energy efficiency evaluation method for cracking furnace is proposed.•Dynamic baselines are determined according to real-time production load.•A set of new energy efficiency indicators is designed and predicted in real time.•The relations of energy efficiency and operation conditions and load are quantified.
Many countries have implemented policies to encourage higher Energy Efficiency (EE) implementation, but they seem insufficient and significant EE opportunities are unrealized. It is thus important to ...understand which internal strategic drivers can help further improve EE implementation by a firm. We develop a theoretical framework and empirically investigating how corporate strategy influences firms' EE implementation on top of EE policies. Drawing from the literature on Natural-resource-based view and Proactive Environmental Strategy, we hypothesize the impacts of several strategic capabilities, including shared vision, top management support and stakeholder integration on a firm's EE implementation. We test our hypotheses using combined secondary data of 572 publicly traded firms from the CDP report, COMPUSTAT Fundamentals North America and Global, and the World Economic Forum. Our study enriches the literature on firms' perceived EE drivers by dissecting the nuanced impacts of different strategic capabilities and exploring new dimensions. Our findings also suggest important policy insights in encouraging higher industrial EE implementation. It remains important to strengthen EE policies and regulation. However, to make further leaps in EE implementation, policy efforts could be spent in information campaigns helping redirect interpretation of EE improvements toward opportunities and away from risks/threats.
•Policies are important, but insufficient to drive energy efficiency implementation.•Firms' internal strategic capabilities are crucial for a leap in energy efficiency.•The management of climate change should be perceived as opportunities, not risks.
Multi energy demand response is an important measure to achieve the economic and efficient operation of the integrated energy system (IES), which is of great significance to promote the sustainable ...development of the IES. The concept of demand response (DR) is extended to IES, and a double objective operation optimization model of IES considering integrated demand response (IDR) mechanism is proposed. Firstly, based on the electro-thermal IES, this paper proposes a demand response mechanism considering electric load and thermal load. According to the load composition (transferable load, reducible load, adjustable thermal load), the load management strategy is established. Then, based on the DR mechanism of electro-thermal IES, a multi-objective operation optimization model is established for the first time, which takes the economic benefits and comprehensive energy efficiency as the objective function. The model involves the equipment constraint in the process of energy production and energy transmission. The relationship between total operation cost and comprehensive energy efficiency of electro-thermal IES is analyzed in the part of Data, Simulation Results and Analysis. Finally, the results show that the model effectively improves the economic benefits and comprehensive energy efficiency of IES, and reduces the pollutants emissions to a certain extent.
•The information and energy flow framework of an integrated energy system is proposed.•An integrated demand response mechanism considering load composition is established.•A dual objective operation optimization model of integrated energy system is established.•The model aims at economy and comprehensive energy efficiency.•The model can improve the economic, efficiency and environmental benefits of the system.
As a strategy, industrial convergence is an important link in building a new economic system. To explore the impact of industrial convergence on the energy efficiency of manufacturing, we first ...incorporated industrial convergence and energy efficiency into a conventional macro-growth model and output density model, and analyzed the relationship between them at the theoretical level. Then, taking the convergence of the information industry and manufacturing in China as the research object, the impact and transmission mechanism of industrial convergence on energy efficiency were empirically investigated. Furthermore, three new techno-economic relevance matrices were constructed to study the spillover effect of industrial convergence using a spatial autoregressive combined model. The results showed that: (1) Industrial convergence improved the energy efficiency of manufacturing, which remained robust after overcoming endogeneity. Moreover, there was a scale effect whereby the deeper the convergence, the greater the marginal effect. (2) There was a spillover effect with regard to industrial relevance. Through cross-industry imitation and learning, industrial convergence improved the energy efficiency of the entire manufacturing sector. (3) Technological innovation was an effective mediating channel for industrial convergence to function. Industrial convergence not only had a direct impact on technological innovation, but also had an indirect impact through industrial scale expansion and factor structure optimization, thereby improving energy efficiency. Our findings provided insights for newly industrialized countries to promote the convergence of informatization and industrialization in an effort to transform and upgrade manufacturing.
•The impact of industrial convergence on manufacturing energy efficiency in China is investigated.•Two models of the relationship between industrial convergence and energy efficiency are derived.•Industrial convergence has a positive effect on improving energy efficiency.•A spatial autoregressive combined model is employed to examine the inter-industry spillovers.•Positive impacts on technological innovation, scale expansion and factor structure optimization are main influence channels.
The energy efficiency gap has been presented as a prevalent paradox in the literature as individuals and firms fail to invest money or effort in seemingly highly profitable efficiency improvements. ...This article contributes to answering which management tools promote the realization of economic energy savings. This article first provides a comparison of the barriers to energy efficiency in firms from the literature with the prescriptions of ISO standards for energy management. Second, we provide empirical evidence that such ISO-certified large Austrian firms increased implementation of energy efficiency measures by 165% compared to those firms with business-as-usual decision-making methods. These higher conservation efforts observed support the hypothesis that ISO standards are an effective instrument to overcome efficiency barriers in an economic way. The main contributing factors for this achievement are the internalization of the identification process of savings potentials and setting up a stringent decision-making and governance process, thereby increasing implementation rates of measures.
Mika H. Sipponen
Angewandte Chemie,
September 13, 2021, Volume:
60, Issue:
38
Journal Article
Peer reviewed
Open access
“The most important future applications of my research are energy efficiency and environmentally friendly materials … Young professors are not prepared for the amount of emailing and housekeeping ...tasks that are out there for you …“ Find out more about Mika Sipponen in his Introducing … Profile.
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