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Visible (VIS) and near-infrared (NIR) mechanoluminescence (ML) materials have been developed rapidly for use in energy conversion, biological applications and mechanical sensing. The realization of visible and NIR ML in single host materials meets the dual requirements of visualization and anti-interference for high-precision mechanical sensing. In this work, Mn2+ single-doped magnesium aluminate spinel MgAl2O4 with excellent ML performance was studied in detail. Bright, visible green and NIR ML were achieved under mechanical stimulation, and the ratio between visible and NIR ML intensity can be regulated by manipulating the doping concentration of Mn2+. The generation of ML without additional pre-irradiation proved that the self-powered ML phenomenon was independent of trap. The functional relationship between mechanical parameters and ML intensity indicated that the doped spinel can be used for visualization, anti-interference and non-contact mechanical sensing. In addition, the NIR ML of MgAl2O4:Mn2+, centered at 835 nm, is located in the first NIR window (NIR-I, 650–950 nm), which effectively penetrates living tissue such as skin, fat, and lean meat, respectively, showing that it has potential applications in in vivo optical imaging. [ABSTRACT FROM AUTHOR]

Cache is the bridge between CPU and memory for data exchange, which consumes up to 45% of the entire CPU energy. Low power cache and memory are urgently required for the computer system. The paper focuses on using Destiny to simulate the scaling roadmap of the STT-MRAM. The performance evaluation of the STT-MRAM is explored in the cache applications, including the cell area, the aspect ratio for different cache capacities. Based on the exploration, optimisation on the performance is achieved, showing a write latency reduction of up to 5.4% and a total leakage power reduction of up to 42.1%, suggesting an important application scenario for the STT-MRAM. Furthermore, comparison is conducted in the cache performance between SRAM and STT-MRAM using high performance (HP) and low power performance (LOP) device models, including the capacity, total area, hit latency, write latency, total leakage power, hit dynamic energy and write dynamic energy. It is interesting to disclose that the STT-MRAM memory bank with large-capacity (> 32 MB) shows better performances. The large cache with the STT-MRAM exhibits better performances than the cache based on the SRAM. Especially for the STT-MARM using LOP device model compared with the SRAM using LOP device model, it can effectively reduce energy consumption. [ABSTRACT FROM AUTHOR]

Integrated circuits operated in the near-threshold region exhibit specific merit with high energy efficiency. A near-threshold model is highly required for the circuit design. In this paper, a near-threshold drain current model is proposed based on the surface inversion layer charge model for analyzing digital circuits. The short-channel effect in deep submicrometer is also included in the model. Moreover, the delay and energy parts based on the near-threshold drain current model are derived and integrated in the model. Two process design kits (PDKs) are used for parameter extraction to demonstrate the feasibility of the proposed model. The results show that the proposed model can be used for the near-threshold circuit calculation, with the benefit of high accuracy. [ABSTRACT FROM AUTHOR]

Cold is an important cause of the death of people who fall into the water. The use of a gas generating agent to inflate an inflatable lifejacket is a kind of self-heating inflatable lifejacket, which maintains the inflation effect and portability of the original lifejacket and can also play an auxiliary heating effect. In this paper, a nitrogen-rich substance, 5-aminotetrazole 3-nitro-1,2,4-triazole (5ATNTZ) was synthesized, together with the selected oxidant and binder to complete the preparation of the gas generating agent. Commercial life jackets were selected for inflation test to explore the actual dosage and inflation effect of gas generating agent. The experimental results show that when the amount of gas generating agent is 19 g, the amount of physical coolant is 20 g, and the amount of chemical coolant is 7 g, the lifejacket is inflated and its surface temperature reaches at least 40.3 °C. The energy utilization efficiency reaches 75.17% when the chemical energy of the gas generating agent is converted into the heat of the bag and inflation work in the whole inflation process. Therefore, the gas-filled lifejacket using a gas generating agent has a good auxiliary heat effect, and is a type of self-heating inflatable lifejacket with excellent performance, which has great application value. • 5-aminotetrazole 3-nitro-1,2,4-triazole is synthesized and applied in gas generating agent firstly. • A gas generating agent with high gas production and low sensitivity is designed to inflate the lifejacket airbag. • The lifejacket is inflated and its surface temperature reaches at least 40.3 °C. • The energy utilization efficiency reaches 75.17% in the whole inflation process. • Gas generator has better performance than carbon dioxide cylinder in keeping warm of the lifejacket. [ABSTRACT FROM AUTHOR]

Selecting a set of reasonable milling parameters of computerized numerical control (CNC) machines is of great importance in decreasing energy consumption and enhancing processing productivity. However, existing works pay little attention to the optimization of energy-conscious milling parameters. This work establishes a dual-objective optimization model for the selection of milling parameters such that power consumption and process time are minimized. With multiple constraints of milling processing conditions, an improved artificial bee colony (ABC) intelligent algorithm is used to handle the proposed dual-objective optimization model. Compared with the non-dominated sorting genetic algorithm (NSGA-II), our improved algorithm has good performance. [ABSTRACT FROM AUTHOR]

As operation cost and energy consumption problems deteriorate with network densification toward 5G, traditional radio resource management and networking strategies must be upgraded. It is observed that when the access network is dealing with a large amount of user traffic, the backhaul (BH) network turns out to be the new bottleneck hindering the cellular system from further increasing its capacity and efficiency. Although wired transmission technologies, such as passive optic fiber networks, are generally available between base stations, the resulting capital expenditure and operational expenditure are prohibitive in an ultradense deployment scenario. To redesign the BH network in 5G, multihop millimeter‐wave transmission is considered as a cost‐efficient and well‐performing candidate. In this paper, we propose a low‐complexity method based on millimeter‐wave transmission to minimize the energy consumption from both the access network and the BH network through joint admission‐power‐traffic control. Concretely, a self‐organizing heuristics is created through which the access and backhaul joint energy efficiency of both the base station and the whole system is maximized under the assumption of predefined user rate requirements. Simulation results show that our proposed method achieves significant reduction (∼95%) in algorithm execution time compared with the branch‐and‐bound search at the expense of little extra energy cost (∼7%). In addition, our proposed method satisfies the quality‐of‐service requirements of user equipment in the system with a lower transmission delay in terms of hops than that of the branch‐and‐bound search. A baseline algorithm called MR‐MPF (maximum reference signal receiver power admission control with minimum power flooding) is also compared to demonstrate our algorithm's superiority in energy saving. Our method is a low‐complexity heuristics comparing with the branch‐and‐bound (BnB) search with very limited extra energy cost (∼7%). Our method yields a lower transmission delay in terms of hops than the exhaustive search method, eg, BnB. Our method transforms the original MILP energy consumption minimization problem into a convex access and backhaul joint energy efficiency maximization problem, which is a novel design for the joint optimization of both the access and backhaul networks. [ABSTRACT FROM AUTHOR]

Abstract The high-power mechanical pumps used in thermal power plants consume a considerable amount of electrical energy. Thus it is of great importance to improve the efficiency from every potential feature of such pumps. In this study, the clocking position of the pump, defined as the circumferential position of the vaned diffuser relative to the circular casing, is investigated to improve the hydraulic performance. Thereafter, the flow loss visualization method is employed to depict the loss caused by clocking positions with the help of entropy production theory based on computational fluid dynamics (CFD). The numerical results are then validated by experiments. At the design condition, the numerical maximum difference in the hydraulic efficiency is 2.61% while the head of each scheme meets the design requirement. The clocking position influences the total pressure loss coefficient more in the circular casing than other components, and the largest difference in the circular casing is 1.91%. Furthermore, the proven visualization method reveals that the clocking position introduces additional flow losses in the circular casing of the worst scheme, and even increases the loss in the vaned diffuser. This study can also provide a new perspective to investigate the optimal assembly strategy for other hydraulic machinery. Highlights • Clocking position has an increasing effect on the relative head as flow rate rises. • Clocking effect influences the hydraulic efficiency at design and overload flows. • Clocking effect introduces more losses in the circular casing than other components. • Additional losses are visualized and located by using entropy production theory. • Fluid impinging on the boundary wall and main flow results in additional losses. [ABSTRACT FROM AUTHOR]

• First reviews on coupling utilisation of thermal sources in vapour compression heat pumps. • The existing thermal source coupling attempts in applied energy fields are summarised and compared. • Design features and performance enhancement principles are analysed in detail. • Recommendations for research and marketisation of energy source coupling methods are made. Vapour compression heat pump provides efficient cooling and heating through the use of various renewable energy sources and plays a significant role in the energy conservation of modern buildings. Its performance enhancement gains increasing attention under the background of conventional energy and environmental crisis. Since the efficiency of a heat pump cycle is closely related to its thermal source condition, a stable high-temperature heat source or low-temperature cold source could benefit its heating or cooling efficiency a lot. Following this improvement strategy, significant progress has been made over the past years on the use of different renewable energy sources as coupled thermal sources of heat pumps. However, a specialised review that summarises relevant studies remains to be published. This paper aims at presenting operating mechanisms, characteristics, benefits, and limitations of different energy source coupling methods for heat pump performance enhancement towards its building application. The most concerning research on solar-assisted air source heat pumps, solar-assisted ground source heat pumps, and air-ground dual source heat pumps is emphasised. The existing thermal source coupling attempts under other renewable energy fields, such as waste heat, biomass, and water sources, are also summarised. Recommendations for further research and marketisation of such technologies are made based on detailed performance characterisation and comparison. The review is expected to benefit researchers in heat pumps and relevant applied energy fields to understand the challenges and opportunities in thermal source coupling technology and to promote its research and application development. [ABSTRACT FROM AUTHOR]

The world energy consumption is currently growing at an alarming rate to support the increase of the world economy and population, which has brought a host of environmental issues. Improving energy efficiency is considered as the crucial solution for changing this situation. The widespread use of inline pumps in the water supply consumes a large amount of electricity, while the efficiency of such devices is lower than the average level. This research is aimed to study the relationship between the shape of the curved inlet pipe and the energy loss distributions by using flow loss visualization technology and correlation analysis. An induced vane was placed at the end of the inlet pipe to suppress the flow phenomena that cause efficiency losses. 700 designs of the inlet pipe with induced vane were generated and calculated to support the research using the automatic simulation approach. An optimization work was also presented to improve the comprehensive performance of the inline pump by using the multi-layer feed-forward neural network and multi-objective particle swarm optimization. An excellent performance improvement was found after the optimization, and a deep analysis of four different design schemes based on the loss visualization method was presented to figure out the main reasons for hydraulic losses in the curved inlet pipe. • An induced vane was added to suppress efficiency losses. • Correlation between inlet profile and performance was investigated. • An optimization method based on automatic simulation program was presented. • Loss visualization method was applied for flow analysis. • Multiple design schemes were compared to figure out application constraints. [ABSTRACT FROM AUTHOR]