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A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

《能源前沿（英文）》 2023年第17卷第4期页码 504-515 doi: 10.1007/s11708-022-0855-3

摘要： Thermal energy storage has been a pivotal technology to fill the gap between energy demands and energy supplies. As a solid-solid phase change material, shape-memory alloys (SMAs) have the inherent advantages of leakage free, no encapsulation, negligible volume variation, as well as superior energy storage properties such as high thermal conductivity (compared with ice and paraffin) and volumetric energy density, making them excellent thermal energy storage materials. Considering these characteristics, the design of the shape-memory alloy based the cold thermal energy storage system for precooling car seat application is introduced in this paper based on the proposed shape-memory alloy-based cold thermal energy storage cycle. The simulation results show that the minimum temperature of the metal boss under the seat reaches 26.2 °C at 9.85 s, which is reduced by 9.8 °C, and the energy storage efficiency of the device is 66%. The influence of initial temperature, elastocaloric materials, and the shape-memory alloy geometry scheme on the performance of car seat cold thermal energy storage devices is also discussed. Since SMAs are both solid-state refrigerants and thermal energy storage materials, hopefully the proposed concept can promote the development of more promising shape-memory alloy-based cold and hot thermal energy storage devices.

关键词： shape-memory alloy (SMA) elastocaloric effect (eCE) cooled seat cold thermal energy storage

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A hot future for cool materials

《能源前沿（英文）》 2023年第17卷第4期页码 447-449 doi: 10.1007/s11708-022-0854-4

摘要： The widespread need to pump heat necessitates improvements that will increase energy efficiency and, more generally, reduce environmental impact. As discussed at the recent Calorics 2022 Conference, heat-pump devices based on caloric materials offer an intriguing alternative to gas combustion and vapor compression.

关键词： magnetocaloric electrocaloric mechanocaloric elastocaloric barocaloric

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Efficiency characteristics of piezostack pump for linear actuators

Junwu KAN, Kehong TANG, Chenghui SHAO, Guoren ZHU, Taijiang PENG,

《机械工程前沿（英文）》 2009年第4卷第4期页码 407-414 doi: 10.1007/s11465-009-0049-2

摘要： A piezostack pump for linear actuators is presented and studied in terms of mechanical energy efficiency (MEE), energy conversion efficiency (ECE) and design method. MEE is defined as the ratio of the output mechanical energy to that converted from input electrical energy, and ECE is the ratio of output mechanical energy to input electrical energy. The analysis results show that both MEE and ECE decrease with the increase of stiffness of the chamber diaphragm (), which is a function of the radius ratio (rigid disk radius to chamber radius). There is respective optimal external load () for them to achieve peak value for a given piezostack with blocked force () and stiffness (). The optimal force ratio (/) is a constant of 0.5 for maximum MEE, and between 0.57 and 0.5 for maximum ECE. Considering the deflection of the pump chamber and dynamic response of the piezostack, the stiffness ratio (/) should be limited between 0.3 and 1, and the relative radius ratio is between 0.7 and 0.8. With the increase of the radius ratio in the range, the maximal MEE decreases from 0.38 to 0.25, and the peak ECE decreases from 0.20 to 0.14.

关键词： piezostack actuator piezostack pump mechanical efficiency energy conversion efficiency (ECE)

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互易域上的仿生密码系统：DNA链变异以保护健康数据 Research Articles

S. AASHIQ BANU, Rengarajan AMIRTHARAJAN

《信息与电子工程前沿（英文）》 2021年第22卷第7期页码 940-956 doi: 10.1631/FITEE.2000071

摘要：医疗保健和远程医疗行业依赖于互联网技术，数字健康数据更易受到网络攻击，因其中包含大量个人数据，因而，有必要保护数字医疗图像以及保证其安全传输。本文采用基于洛伦兹和吕混沌吸引子突变的DNA加密技术生成强伪随机密钥流。为增强混淆与扩散阶段的近似性系数，所提的混沌DNA加密系统在整数小波变换域和一个生物启发的交叉变异单元上运行。进而，使用组合演化吸引子中的量化混沌集进行异或运算。该算法可以获得平均信息熵7.9973，几乎接近于零相关性的像素变化率（number of pixel change rate, NPCR）99.642%，归一平均强度变化（unified average change in intensity, UACI）33.438%，以及密钥空间10203。此外，实验分析和基于美国国家标准与技术研究院（NIST）的统计测试套件测试证实，所提医疗图像加密技术具有抵御任何统计、差分和暴力攻击的能力。

关键词：医学图像加密；DNA；混沌吸引子；交叉；突变；电子医疗

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Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

ZHOU Hongbo, CHEN Zhuchang

《结构与土木工程前沿（英文）》 2007年第1卷第4期页码 458-463 doi: 10.1007/s11709-007-0062-7

摘要： Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile), the end effect on skin friction of bored pile is studied. The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end. The degradation degree of skin friction is deduced with the increase of the distance from pile end. The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile. The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.

关键词： distance different concept additional bottom

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A review on different theoretical models of electrocaloric effect for refrigeration

《能源前沿（英文）》 2023年第17卷第4期页码 478-503 doi: 10.1007/s11708-023-0884-6

摘要： The performance parameters for characterizing the electrocaloric effect are isothermal entropy change and the adiabatic temperature change, respectively. This paper reviews the electrocaloric effect of ferroelectric materials based on different theoretical models. First, it provides four different calculation scales (the first-principle-based effective Hamiltonian, the Landau-Devonshire thermodynamic theory, phase-field simulation, and finite element analysis) to explain the basic theory of calculating the electrocaloric effect. Then, it comprehensively reviews the recent progress of these methods in regulating the electrocaloric effect and the generation mechanism of the electrocaloric effect. Finally, it summarizes and anticipates the exploration of more novel electrocaloric materials based on the framework constructed by the different computational methods.

关键词： electrocaloric effect effective Hamiltonian phase-field modeling different theoretical models

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A new miniaturized engine based on thermomagnetic effect of magnetic fluids

Lujun ZHOU, Yimin XUAN, Qiang LI, Wenlei LIAN

《能源前沿（英文）》 2009年第3卷第2期页码 160-166 doi: 10.1007/s11708-009-0018-9

摘要： A new engine system, essentially consisting of a permanent NdFeB magnet, a kerosene-based magnetic fluid and a rotor, is proposed based on the thermomagnetic effect of a temperature-sensitive magnetic fluid. The rotor was driven by the thermal convection of the magnetic fluid in the presence of a homogeneous external magnetic field. A digital camera was used to record the rotation speed of the rotor to investigate the performance of the engine system under varying conditions such as heat load, heat sink temperature, and magnetic field distribution. The peak angle velocity obtained for the rotor was about 2.1 rad/min. The results illustrate that the rotation speed of the rotor increases as the input heat load increases, or as the heat sink temperature decreases. The performance of the motor is considerably influenced by the magnetic field imposed. Therefore, the performance of such an engine can be controlled conveniently by changing the external magnetic field and/or the temperature distribution in the fluid.

关键词： magnetic fluid thermomagnetic effect engine

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The cooperation effect of Ni and Pt in the hydrogenation of acetic acid

《化学科学与工程前沿（英文）》 2022年第16卷第3期页码 397-407 doi: 10.1007/s11705-021-2076-4

摘要： The catalytic hydrogenation of carboxylic acid to alcohols is one of the important strategies for the conversion of biomass. Herein, a series of Ni-doped PtSn catalysts were prepared, characterized and studied in the hydrogenation of acetic acid. The Ni dopant has a strong interaction with Pt, which promotes the hydrogen adsorption, providing an activated hydrogen-rich environment for the hydrogenation. Meanwhile, the presence of Ni also improves the Pt dispersion, giving more accessible active sites for hydrogen activation. The cooperation of Pt and Ni significantly promotes the catalytic activity of the hydrogenation of acetic acid to ethanol. As a result, the catalyst with 0.1% Ni exhibits the best reaction activity, and its space time yield is twice as that of the PtSn/SiO₂ catalyst. It provides a meaningful instruction on the catalyst design for the carboxylic acid hydrogenation.

关键词： acetic acid ethanol hydrogenation Pt Ni cooperation effect

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Direct energy rebound effect for road transportation in China

《工程管理前沿（英文）》页码 597-611 doi: 10.1007/s42524-023-0276-y

摘要： The enhancement of energy efficiency stands as the principal avenue for attaining energy conservation and emissions reduction objectives within the realm of road transportation. Nevertheless, it is imperative to acknowledge that these objectives may, in part or in entirety, be offset by the phenomenon known as the energy rebound effect (ERE). To quantify the long-term EREs and short-term EREs specific to China’s road transportation, this study employed panel cointegration and panel error correction models, accounting for asymmetric price effects. The findings reveal the following: The long-term EREs observed in road passenger transportation and road freight transportation range from 13% to 25% and 14% to 48%, respectively; in contrast, the short-term EREs in road passenger transportation and road freight transportation span from 36% to 41% and 3.9% to 32%, respectively. It is noteworthy that the EREs associated with road passenger transportation and road freight transportation represent a partial rebound effect, falling short of reaching the magnitude of a counterproductive backfire effect. This leads to the inference that the upsurge in energy consumption within the road transportation sector cannot be solely attributed to advancements in energy efficiency. Instead, various factors, including income levels, the scale of commodity trade, and industrial structure, exert more substantial facilitating influences. Furthermore, the escalation of fuel prices fails to dampen the demand for energy services, whether in the domain of road passenger transportation or road freight transportation. In light of these conclusions, recommendations are proffered for the formulation of energy efficiency policies pertinent to road transportation.

关键词： road transportation direct energy rebound effect asymmetric price effects panel data model

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Photoaging mechanism of microplastics: a perspective on the effect of dissolved organic matter in natural

《环境科学与工程前沿（英文）》 2023年第17卷第11期 doi: 10.1007/s11783-023-1743-8

摘要：

● Microplastics (MPs) undergo photoaging in natural water under light irradiation.

关键词： Microplastics Photoaging Dissolved organic matter ROS generation

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Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

《能源前沿（英文）》 2019年第13卷第1期页码 193-203 doi: 10.1007/s11708-019-0608-0

摘要： Recently the porous bilayer wood solar collectors have drawn increasing attention because of their potential application in solar desalination. In this paper, a thermodynamic model has been developed to analyze the performance of the wood solar collector. A modeling analysis has also been conducted to assess the performance and operating conditions of the multiple effect desalination (MED) system integrated with the porous wood solar collector. Specifically, the effects of operating parameters, such as the motive steam temperature, seawater flow rate, input solar energy and number of effects on the energy consumption for each ton of distilled water produced have been investigated in the MED desalination system combined with the bilayer wood solar steam generator. It is found that, under a given operating condition, there exists an optimum steam generation temperature of around 145°C in the wood solar collector, so that the specific power consumption in the MED system reaches a minimum value of 24.88 kWh/t. The average temperature difference is significantly affected by the solar heating capacity. With the solar capacity increasing from 50 kW to 230 kW, the average temperature difference increases from 1.88°C to 6.27°C. This parametric simulation study will help the design of efficient bilayer wood solar steam generator as well as the MED desalination system.

关键词： solar energy steam generating multi-effect desalination

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十二系列叔胺捕收剂对高岭石的浮选研究

曹学锋,刘长淼,胡岳华

《中国工程科学》 2011年第13卷第1期页码 93-97

摘要：

研究4种十二取代叔胺（DRN，DEN，DPN和DBN）对高岭石的浮选行为。发现4种叔胺对高岭石的浮选捕收能力都较好，其中DEN最好，浮选回收率最高可达92 %以上。4种叔胺主要依靠静电引力吸附在高岭石表面，在酸性pH范围内，浮选高岭石的回收率较高，随着pH的增大，叔胺的阳离子组分减少，使得浮选回收率下降。Zeta电位研究表明，高岭石在整个pH范围内，表面主要带负电，4种叔胺与高岭石作用后，能显著增加高岭石的Zeta电位。红外光谱研究表面，4种叔胺主要与高岭石表面发生了电性作用的物理吸附。叔胺中N原子上的取代基的给电子效应和空间位阻效应是造成 4 种叔胺浮选能力差异的主要原因。

关键词：叔胺高岭石浮选静电作用电子效应空间效应

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Phase transition regulation and caloric effect

《能源前沿（英文）》 2023年第17卷第4期页码 463-477 doi: 10.1007/s11708-023-0860-1

摘要： Solid state refrigeration based on caloric effect is regarded as a potential candidate for replacing vapor-compression refrigeration. Numerous methods have been proposed to optimize the refrigeration properties of caloric materials, of which single field tuning as a relatively simple way has been systemically studied. However, single field tuning with few tunable parameters usually obtains an excellent performance in one specific aspect at the cost of worsening the performance in other aspects, like attaining a large caloric effect with narrowing the transition temperature range and introducing hysteresis. Because of the shortcomings of the caloric effect driven by a single field, multifield tuning on multicaloric materials that have a coupling between different ferro-orders came into view. This review mainly focuses on recent studies that apply this method to improve the cooling performance of materials, consisting of enlarging caloric effects, reducing hysteresis losses, adjusting transition temperatures, and widening transition temperature spans, which indicate that further progress can be made in the application of this method. Furthermore, research on the sign of lattice and spin contributions to the magnetocaloric effect found new phonon evolution mechanisms, calling for more attention on multicaloric effects. Other progress including improving cyclability of FeRh alloys by introducing second phases and realizing a large reversible barocaloric effect by hybridizing carbon chains and inorganic groups is described in brief.

关键词： phase transition regulation caloric effect solid state refrigeration

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Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

《结构与土木工程前沿（英文）》 2010年第4卷第1期页码 116-126 doi: 10.1007/s11709-010-0014-5

摘要： Studies show that the dynamic properties of rockfill are strongly dependent on the confining pressure. Therefore, confining pressure effect has become a very important factor in the seismic analysis of high rockfill dam. The relationships of dynamic shear modulus versus dynamic shear strain and damping ratio versus dynamic shear strain had been improved to a certain degree on the basic of widely used Hardin-Drnevich constitutive model in this paper. Then a new model that could consider confining pressure effect has been established. Regression analysis was carried out of the dynamic triaxial experimental data of the damming materials in the Changheba hydropower station of Sichun Province, China. The results show that, the new model can fit the test data well under various confining pressures. A corresponding computational procedure was compiled and applied in the dynamic response analysis of the Changheba Dam. Comparing the calculation results between the new constitutive model and the ordinary Hardin-Drnevich model, it can be seen that the result is conservative to some extent without considering confining pressure effect.

关键词： confining pressure effect high rockfill dam dynamic response Hardin-Drnevich constitutive model

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A review of salting-out effect and sugaring-out effect: driving forces for novel liquid-liquid extraction

Chuhan Fu, Zhuoxi Li, Zengran Sun, Shaoqu Xie

《化学科学与工程前沿（英文）》 2021年第15卷第4期页码 854-871 doi: 10.1007/s11705-020-1980-3

摘要： Biofuels and bio-based chemicals are getting more and more attention because of their sustainable and renewable properties and wide industrial applications. However, the low concentrations of the targeted products in their fermentation broths, the complicated components of the broths and the high energy-intensive separation and purification process hinder the competitiveness of biofuels and biochemicals with the petro-based ones. Hence, the production and the separation of biofuels and bio-based chemicals in energy-saving, low-cost and greenness ways become hot topics nowadays. This review introduces the separation technologies (salting-out extraction, salting-out, sugaring-out extraction, and sugaring-out) that extract biobutanol, 1,3-propanediol, 2,3-butanediol, acetoin, organic acids and other bio-based chemicals from fermentation broths/aqueous solutions. Salting-out/sugaring-out extraction and salting-out/sugaring-out technologies display the high separating efficiency and the high targeted product yields. In addition, they are easy to operate and require low cost for separating products. Hence, they are the effective and potential technologies for separating targeted products in the wide industrial applications. The successful research into the salting-out/sugaring-out and salting-out/sugaring-out extraction not only affords biofuels and biochemical but also opens a door for the development of novel separation methods.

关键词： salting-out sugaring-out extraction biofuels biochemicals application