Distributional Domain-Invariant Preference Matching for Cross-Domain Recommendation

Learning accurate cross-domain preference mappings in the absence of overlapped users/items has presented a persistent challenge in Non-overlapping Cross-domain Recommendation (NOCDR). Despite the efforts made in previous studies to address NOCDR, several limitations still exist. Specifically, 1) while some approaches substitute overlapping users/items with overlapping behaviors, they cannot handle NOCDR scenarios where such auxiliary information is unavailable; 2) often, cross-domain preference mapping is modeled by learning deterministic explicit representation matchings between sampled users in two domains. However, this can be biased due to individual preferences and thus fails to incorporate preference continuity and universality of the general population. In light of this, we assume that despite the scattered nature of user behaviors, there exists a consistent latent preference distribution shared among common people. Modeling such distributions further allows us to capture the continuity in user behaviors within each domain and discover preference invariance across domains. To this end, we propose a Distributional domain-invariant Preference Matching method for non-overlapping Cross-Domain Recommendation (DPMCDR). For each domain, we hierarchically approximate a posterior of domain-level preference distribution with empirical evidence derived from user-item interactions. Next, we aim to build distributional implicit matchings between the domain-level preferences of two domains. This process involves mapping them to a shared latent space and seeking a consensus on domain-invariant preference by minimizing the distance between their distributional representations therein. In this way, we can identify the alignment of two non-overlapping domains if they exhibit similar patterns of domain-invariant preference.Comment: 9 pages, 5 figures, full research paper accepted by ICDM 202

Enhanced mechanical properties of a chip-based Al-Si-Cu-Fe alloy with an in-situ emulsion decomposition recycled by solid-state processing

The effects of a residual emulsion and its in-situ decomposition on the microstructure and mechanical properties of an Al-Si-Cu-Fe aluminum alloy recycled by hot extrusion in the solid-state were studied. Tensile tests reveal superior mechanical properties of hot extruded chips that are pre-heated at 623 K. The results indicate that the in-situ formation of carbon-rich phase is dispersed finely and homogeneously in the recycled specimens using hot extrusions and results in a better interfacial bonding between the matrix and alumina. Thus, the yield strength and tensile strength increase exceeded a factor of 1.2, and the elongation increased approximately 3% compared to that of recycled specimens prepared using clean chips. Keywords: In-situ decomposition, Mechanical properties, Microstructure, Solid-state recycling, Aluminum allo

Microstructures and mechanical properties of SCF/AZ31B composites fabricated by multi-times hot-extrusion

Magnesium matrix composites reinforced with short carbon fiber (SCF) (SCF/AZ31B composites) were fabricated by multi-times hot-extrusion with mass fraction of 3%. The effect of extrusion times and addition of SCFs on microstructure, mechanical properties of the composites were investigated. The results show that the size of grain was initially decreased while increasing the extrusion times, and SCFs were dispersed uniformly in the composites after quadruple-extrusion. The yield strength (YS) and ultimate tensile strength (UTS) of the quadruple-extruded SCF/AZ31B composites were increased by 50.15% and 63.60%, respectively, compared with the extruded AZ31B magnesium alloy. The fracture mechanism of SCF/AZ31B composite is dominated by brittle fracture. In addition, the grain refinement is attributed to dynamic recrystallization during plastic deformation and dislocations motion inhibited by SCFs. Multi-times hot-extrusion is an effective synthesis method to fabricate SCF reinforced Mg-based composites. Keywords: Short carbon fibers, Mg-matrix composite, Multi-times hot-extrusion, Dynamic recrystallization, Dislocatio

Dynamic recrystallization behavior and mechanical properties of bimodal scale Al2O3 reinforced AZ31 composites by soild state synthesis

In this paper, (500 nm 1% +5 µm 3%) bimodal scale Al2O3p/AZ31 composites was fabricated by solid state synthesis and the effect of bimodal scale Al2O3 particulates on its dynamic recrystallization behavior and mechanical properties was investigated. The optical microscopy, scanning electron microscopy, transmission electron microscopy and electron universal strength tester composites were used to characterize the composites. The results indicate that the grains size of the composites are significantly refined and the mechanical properties are obviously improved. Due to the presence of  the bimodal scale Al2O3 particulates, the high-density dislocation zone is formed around nano-Al2O3p and the particle deformation zone is formed near micron-Al2O3p. These zones are ideal sites for the formation of recrystallization nucleus. Meanwhile, the addition of the bimodal scale Al2O3 particulates may delay or hinder the growth of matrix grain through the pining effect on the grain boundaries, resulting in significantly improving the yield strength and tensile strength of Al2O3p/AZ31 composites

A Study of the Mechanical and Thermal Characteristics of an Al-Si-Fe Alloy Fabricated by Rolling and Heat Treatment

The effects of a rolling process and heat treatment on the mechanical and thermal properties of an Al-Si-Fe alloy were studied. The achieved thermal conductivity of the as-rolled alloy treated by a T6 heat treatment was 188.22 W/(m·K), which is as good as that of the as-cast alloy treated by the T6 heat treatment directly, mostly because of changes in the silicon morphology. The results also revealed that the lower quantity of precipitated Al8Fe2Si and Mg2Si phases had no obvious effect on the thermal properties of the material because the interphase spaces between precipitated phases were larger than the mean free path of electrons. However, the precipitated second phases influenced the elongation. The best mechanical properties of the Al-Si-Fe alloy were obtained by rolling and T6 treatment. The corresponding best tensile strength, yield strength, and elongation were 244 MPa, 295 MPa, and 9.56%, respectively, which are attributed to the near-spherical shape, small size, homogeneous distribution of the Si particles, and the precipitation strengthening of Mg2Si

sj-docx-1-pie-10.1177_09544089231215226 - Supplemental material for Effect of modification and subsequent heat treatment on thermal and mechanical properties of near-eutectic Al-Si-Fe-Mg alloys

Supplemental material, sj-docx-1-pie-10.1177_09544089231215226 for Effect of modification and subsequent heat treatment on thermal and mechanical properties of near-eutectic Al-Si-Fe-Mg alloys by Ye Wang, Jinlin Li, Yu Guo, Bo Jiang, Maoliang Hu and Zesheng Ji in Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering</p

sj-docx-2-pie-10.1177_09544089231215226 - Supplemental material for Effect of modification and subsequent heat treatment on thermal and mechanical properties of near-eutectic Al-Si-Fe-Mg alloys

Supplemental material, sj-docx-2-pie-10.1177_09544089231215226 for Effect of modification and subsequent heat treatment on thermal and mechanical properties of near-eutectic Al-Si-Fe-Mg alloys by Ye Wang, Jinlin Li, Yu Guo, Bo Jiang, Maoliang Hu and Zesheng Ji in Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering</p

Evaluation and Optimization of heat Pump Combined District Heating System: A Case Study of China

The district heating area in China is continuously increasing, which brings an increase in district heating load. In order to solve the shortage of heating power and realize the carbon neutral target, this study proposes two retrofit schemes for district heating system by integrating air source heat pump and water source heat pump, respectively. Mathematical models are established to study the performance of the integrated systems and a bilevel optimization model is proposed to optimize them. The results show that the air source heat pump combined district heating system has better performance compared to the conventional system, which reduces 50% energy consumption, 10.8% carbon emissions and achieves better economy. The dynamic coupling property of the district heating network and power grid are also considered, and the results indicate that the introduction of air source heat pump can effectively improve the efficiency and stability of power grid and reduce the seasonal fluctuation. The potential of large-scale application of air source heat pump combined system in Beijing is evaluated. The results reveal that retrofit scheme of integrating air source heat pumps into district heating system can cover 2930 MW heating load and bring 362 million Chinese Yuan profit by reducing 219,000 tons of carbon emissions and 539,000 tons of standard coal consumption in 2025

Evaluation and Optimization of heat Pump Combined District Heating System: A Case Study of China

The district heating area in China is continuously increasing, which brings an increase in district heating load. In order to solve the shortage of heating power and realize the carbon neutral target, this study proposes two retrofit schemes for district heating system by integrating air source heat pump and water source heat pump, respectively. Mathematical models are established to study the performance of the integrated systems and a bilevel optimization model is proposed to optimize them. The results show that the air source heat pump combined district heating system has better performance compared to the conventional system, which reduces 50% energy consumption, 10.8% carbon emissions and achieves better economy. The dynamic coupling property of the district heating network and power grid are also considered, and the results indicate that the introduction of air source heat pump can effectively improve the efficiency and stability of power grid and reduce the seasonal fluctuation. The potential of large-scale application of air source heat pump combined system in Beijing is evaluated. The results reveal that retrofit scheme of integrating air source heat pumps into district heating system can cover 2930 MW heating load and bring 362 million Chinese Yuan profit by reducing 219,000 tons of carbon emissions and 539,000 tons of standard coal consumption in 2025