Physical and sensory properties of lemon-flavored acidic beverages formulated with nonfat dry milk during storage

Sensory and physical properties of 2 lemon-flavored beverages with 5% and 7.5% wt/wt nonfat dry milk (NFDM) at pH 2.5 were studied during storage. The 2 beverages had similar volatile compounds, but the 5% NFDM had higher aroma and lemon flavor, with a preferred appearance by consumers due to the lower turbidity and viscosity. After 28 d of storage at 4°C, lemon flavor decreased in the 5% NFDM beverage but was still more intense than the 7.5% one. During 70 d of storage, no microorganisms were detected, and the beverages were more stable when stored at 4°C than at room temperature according to changes of physical properties measured for appearance, turbidity, color, particle size, zeta potential, rheological properties, and transmission electron microscopy morphology. Findings of the present study suggest that NFDM may be used at 5% wt/wt to produce stable acidic dairy beverages with low turbidity when stored at 4°C.     

Numerical study of strain development in high-density polyethylene geomembrane liner system in landfills using a new constitutive model for municipal solid waste

Tensile strain development in high-density polyethylene (HDPE) geomembrane (GMB) liner systems in landfills was numerically investigated. A new constitutive model for municipal solid waste (MSW) that incorporates both mechanical creep and biodegradation was employed in the analyses. The MSW constitutive model is a Cam-Clay type of plasticity model and was implemented in the finite difference computer program FLAC?. The influence of the friction angle of the liner system interfaces, the biodegradation of MSW, and the MSW filling rate on tensile strains were investigated. Several design alternatives to reduce the maximum tensile strain under both short- and long-term waste settlement were evaluated. Results of the analyses indicate that landfill geometry, interface friction angles, and short- and long-term waste settlement are key factors in the development of tensile strains. The results show that long-term waste settlement can induce additional tensile strains after waste placement is complete. Using a HDPE GMB with a friction angle on its upper interface that is lower than the friction angle on the underlying interface, increasing the number of benches, and reducing the slope inclination are shown to mitigate the maximum tensile strain caused by waste placement and waste settlement.     

Consolidation considering increasing soil column radius for dredged slurries improved by vacuum preloading method

Soil column is often investigated in the improvement of dredged slurries. Different from the smear zone, the soil column forms gradually and has extremely low permeability. This study presents an analytical solution for soil consolidation considering the increasing radius of the soil column and time-dependent discharge capacity. Based on the solution, the influence of the radius' increase on the consolidation behavior is found significant when the soil column has low permeability and large final radius, and the increase of formation time can lead to the increase of consolidation speed and final consolidation degree.     

Far-red-emitting YAl3(BO3)4:Cr3+ phosphors with excellent thermal stability and high luminescent yield for plant growth LEDs

Phosphors-converted LEDs (pc-LEDs) are excellent artificial light sources for indoor plant cultivation, in which the far-red-emitting component (700−780 nm) plays an important role in regulating the photomorphogenesis of plants. Accordingly, highly efficient and thermally stable far-red-emitting phosphors are indispensable for developing high-performance plant cultivation pc-LEDs. Herein, far-red-emitting YAl₃(BO₃)₄:Cr³⁺ (YAB:Cr³⁺) phosphors were synthesized by solid-state reaction, and their photoluminescence characteristics, thermal quenching, quantum yield (QY), and application in pc-LEDs were systematically investigated. The YAB:Cr³⁺ phosphor has an intense broadband absorption to the blue light, simultaneously exhibiting the sharp-line ²E emission and the broadband ⁴ T₂ emission of Cr³⁺ with a QY of ~86.7%. The far-red broadband emissions of YAB:Cr³⁺ centered at ~735 nm show a high resemblance to the active-state (P_FR) absorption of plant phytochrome. Moreover, the YAB:Cr³⁺ phosphor shows the thermally enhanced luminescence at temperatures of 303−393 K and the near-zero thermal quenching up to 423 K. The anomalous thermal enhancement is attributed to the temperature-dependent repopulation between ²E and ⁴ T₂ states. Finally, a pc-LED device was fabricated with the YAB:Cr³⁺ phosphor and blue chip, exhibiting the light out power of ~50.6 mW and energy conversion efficiency of ~17.4% at 100 mA drive current, respectively. The exceptional PL features including suitable excitation/emission wavelengths, suppressed thermal quenching and high QY make YAB:Cr³⁺ phosphors very promising for applications in plant growth pc-LEDs.     

人工智能赋能在线实验教学行为分析

教学行为分析作是教学质量分析的重要组成部分，也是教学引导与反馈机制的重要依据。文章阐述了人工智能（AI）的含义及发展历程，重点分析总结了教学行为分析方法及AI在教学行为分析上的应用。文章以东南大学电工电子在线实验为研究平台，探索分析了AI技术在实验教学行为分析上的可行性，梳理了基于专家系统的在线实验分析系统的设计思路，充分探讨了“智能”教育在实验教学中的深刻内涵。     

Multi-scale characteristics of magnesium potassium phosphate cement modified by metakaolin

Workability and early-ages mechanical properties are important indicators of magnesium potassium phosphate cement (MKPC) as a repair material. The effect of metakaolin (MK) on the setting time, fluidity and early-ages strength of MKPC paste was studied, and its influence mechanism was analyzed through pore structure, microstructure and nanomechanical properties. The results show that 10% and 20% of MK prolong the setting time of MKPC paste, but excessive MK shortens the setting time of MKPC paste. Meanwhile, incorporating MK reduces the fluidity of MKPC paste, and the early-ages strength of MKPC specimens increases when the substitution ratio of MK is 10%. When 10% of MK is incorporated to the MKPC paste, the 30-d shrinkage of the sample is only 69% of the control group. Meanwhile, a proper amount of MK can improve the pore structure of the MKPC specimen and make its microstructure denser by generating amorphous aluminosilicate phosphate gel. It is observed from the nano-scale characteristics that incorporating 10% MK can reduce the content of pore phase and unreacted MgO phase, and increase the volume fraction of hydration products.     

Enhanced structural,electromagnetic and absorption features of CoSm ferrite-metamaterial absorbers through synergistic effects

Currently, materials with outstanding absorption abilities, such as thin size, better absorbing power, and light weight are the need of industry to resolve the electromagnetic issues. However, the research on optimizing the composition of the material, microstructure and the structure of the absorber are also the important factors for enhancing the absorption features. A metamaterial microwave absorber (MMA) based on nano ferrites with desirable absorption peaks is proposed and simulated. Sol-gel auto combustion route is used to prepare the nanosized Sm doped Co ferrite with Co_1+xSm_xFe_2-2xO₄ at x = 0.00, 0.03, 0.06, 0.09, respectively. XRD, VSM, FESEM, and VNA were employed to evaluate the structural, magnetic, morphological, and dielectric features. Rietveld refinement of the XRD patterns of samples was evaluated. Refined parameters show the spinel phase's emergence and the Fe₂O₃ phase. Grain size and crystallite size were increased with Sm doping in Co ferrite. Electromagnetic studies depicted that the highest dielectric constant value was found at x = 0.09 and the minimum value at x = 0.03, respectively. Sm doped Co ferrite at x = 0.09 depicted high Q values at higher frequencies. The coercivity values first decreased and then increased. All samples exhibit variations in coercivity and magneto-crystalline anisotropy constant. This variation was attributed to the super-exchange interactions and strong LS coupling of the cations. The multiple absorption peaks are attained for TE-polarization, and the absorptivity is considerably improved for x = 0.09. The proposed absorber simulated from CST depicted the absorption peaks of the S-band and C-band of the microwave regime. The synergistic effects among the metamaterial and ferrite layers may enhance the absorption feature and would be useful for satellite communication applications.     

闭式外腔循环太阳能墙集热效果实验研究

文章设计了闭式外腔循环太阳能墙系统,从理论和实验两方面研究太阳能墙传热传质规律。以大连市冬季为研究背景,基于对实验测温点不同时刻的持续监测,从逐时曲线中分析了不同环境下闭式外腔循环系统内部温度以及室内获得热量后室温的变化情况。结果表明,太阳能墙集热效率与太阳辐射强度密切相关,在晴朗天气下,白天部分时段单一太阳能墙就能满足采暖要求,不满足采暖要求时可以选择空气源热泵辅助采暖。     

An improved iterative stochastic multi-objective acceptability analysis method for robust alternative selection in new product development

Alternative selection in new product development (NPD) is a multi-criteria decision-making (MCDM) problem. It usually starts with incomplete, imprecise or even partially missing information. Currently, most existing methods in dealing with this problem cannot work well if required information is incomplete or missing. It is acknowledged that stochastic multi-objective acceptability analysis (SMAA) can be applied to address MCDM problem with incomplete preference information and uncertain criteria measurements. In SMAA, alternatives are evaluated based on SMAA measurements (acceptability index, central weight vector and confidence factor). The discriminability of SMAA for the optimum alternative heavily depends on differences of SMAA measurements among different alternatives. Usually, a large number of alternatives and high level of uncertainty are involved in alternative selection in NPD. In this situation, the differences among SMAA measurements are not obvious, and therefore SMAA cannot deal with such problem very well. To this end, this paper proposes an improved SMAA method called Iterative-SMAA (I-SMAA) for alternative selection in NPD. In the I-SMAA, an iterative multi-step decision-making process is suggested to improve differences of SMAA measurements among different alternatives, and thus assist decision makers (DMs) to positively discern from the most preferred alternative. To enhance the decision-making efficiency, sensitive criteria are acquired in each iteration by ranking sensitivity analysis. DMs are guided to provide partial preference information and give more accurate criteria measurements for sensitive criteria rather than all criteria. Eventually, to verify the proposed method, a numerical example of the existing literature is solved with the method, and the results are compared. And then, a practical example of a preparation equipment for coal samples is further employed to verify the practicability of the proposed I-SMAA.