Facile synthesis of di-mannitol adipate ester-based zinc metal alkoxide as a bi-functional additive for poly(vinyl chloride)

A new di-mannitol adipate ester-based zinc metal alkoxide (DMAE-Zn) was synthesized as a bi-functional poly(vinyl chloride) (PVC) thermal stabilizer for the first time. The materials were characterized with Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterization results confirmed the formation of Zn–O bonds in DMAE-Zn, and confirmed that DMAE-Zn had a high decomposition temperature and a low melting point. The thermal stability of DMAE-Zn on PVC also was tested by a conductivity test, a thermal aging test, and a UV-visible spectroscopy (UV-VIS) test. PVC stabilized by DMAE-Zn had a good initial color and excellent long-term stability. UV-VIS also showed that the conjugated structure in PVC stabilized by DMAE-Zn was almost all of the triene, suggesting that the addition of DMAE-Zn would suppress the formation of conjugated structures above tetraene. The dynamic processing performance of PVC samples tested by torque rheometer indicated that, having a good compatibility with PVC chains in the amorphous regions, DMAE-Zn contributed a good plasticizing effect to PVC. DMAE-Zn thus effectively demonstrates bi-functional roles, e.g., thermal stabilizers and plasticizers to PVC. Furthermore, FT-IR, a HCl absorption capacity test, and a complex ZnCl2 test were also used to verify the thermal stability mechanism of DMAE-Zn for PVC

Wide-field-of-view near-eye display with dual-channel waveguide

We propose a wide-field-of-view near-eye display featuring a dual-channel waveguide with cholesteric liquid crystal gratings. Our dual-channel waveguide is capable of splitting the field of view through the orthogonal polarization division multiplexing. To explain its mechanism, a diagram of k-domain, which factors into both the waveguide size and the number of pupils, is depicted. Our results demonstrate that the diagonal field of view reaches up to 80°, eye relief is 10 mm, exit pupil is 4 × 3 mm2, and uniformity is 79%

A Framework for the Nationwide Multimode Transportation Demand Analysis

This study attempts to analyze the impact of traffic on the US highway system considering both passenger vehicles and trucks. For the analysis, a pseudo-dynamic traffic assignment model is proposed to estimate the time-dependent link flow from the intercity travelers on the network covering the continental U.S. A two-stage simulation scheme was designed to separate the intercity and non-intercity travelers involved in the link flow. The fuel consumption and emissions from the intercity travelers are estimated based on data in Mobile, the emission model developed by EPA. The suggested methodology could be adopted in further deployment of a nationwide transportation system analysis model that supports the evaluation of planned transportation improvement plans. Several suggestions are made for future study

Evaluation of Urban Transportation Resilience under Extreme Weather Events

The frequent occurrence of extreme weather events (EWEs) in recent years has posed major hazards to urban transportation as well as socioeconomic impacts. A quantitative evaluation of the urban transportation resilience to minimize the impact caused by EWEs becomes critical to the rapid recovery of urban transportation after disasters. However, there is, generally, a lack of reliable data sources to monitor urban transportation performance under EWEs. This empirical study proposes a performance indicator (displacement) and quantitative method for evaluating the urban transportation performance under EWEs based on bus GPS trajectory datasets. Furthermore, the transportation resilience of it is quantified, and the variation is compared across temporal and spatial dimensions. The method is applied in a case study of Fuzhou, China, under rainstorm events. The results show that the Gulou and Jinan subareas have the highest transportation resilience during the yellow and red rainstorm warnings. By formulating an emergency plan and taking mitigation measures, the transportation performance in the Jinan subarea during the red rainstorm warning was improved by 36% compared to the yellow rainstorm warning. The empirical study not only fills the knowledge gap for quantifying the transportation resilience across the geographical boundary under rainstorm events, but also estimates the operation status of the road network. The results will help policymakers prioritize the resource distribution and develop effective policies or measures to further improve transportation resilience in the city

Facile Synthesis of Di-Mannitol Adipate Ester-Based Zinc Metal Alkoxide as a Bi-Functional Additive for Poly(Vinyl Chloride)

A new di-mannitol adipate ester-based zinc metal alkoxide (DMAE-Zn) was synthesized as a bi-functional poly(vinyl chloride) (PVC) thermal stabilizer for the first time. The materials were characterized with Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Characterization results confirmed the formation of Zn−O bonds in DMAE-Zn, and confirmed that DMAE-Zn had a high decomposition temperature and a low melting point. The thermal stability of DMAE-Zn on PVC also was tested by a conductivity test, a thermal aging test, and a UV-visible spectroscopy (UV-VIS) test. PVC stabilized by DMAE-Zn had a good initial color and excellent long-term stability. UV-VIS also showed that the conjugated structure in PVC stabilized by DMAE-Zn was almost all of the triene, suggesting that the addition of DMAE-Zn would suppress the formation of conjugated structures above tetraene. The dynamic processing performance of PVC samples tested by torque rheometer indicated that, having a good compatibility with PVC chains in the amorphous regions, DMAE-Zn contributed a good plasticizing effect to PVC. DMAE-Zn thus effectively demonstrates bi-functional roles, e.g., thermal stabilizers and plasticizers to PVC. Furthermore, FT-IR, a HCl absorption capacity test, and a complex ZnCl2 test were also used to verify the thermal stability mechanism of DMAE-Zn for PVC