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This study attempts to formally quantify Jane Jacob’s notion of urban diversity and examine whether greater diversity actually contributes economic benefits to a neighborhood. Focusing on the number and types of stores at the street level, we use the Shannon–Weaver index to quantify commercial diversity. We then compare the obtained degrees of diversity with store sales volumes obtained through credit card transaction data aggregated in the neighborhood divided into a 200-m grid. The results of the analysis, performed on 50 Spanish cities, show that the greater the diversity in the grid, the higher the sales volumes of the stores, and this tendency is more evident in large than in small–medium cities. In addition, we found that the coexistence of different store types provides a positive environment for the emergence of hub stores. We specifically define a hub store in this paper as the store with the largest revenue within a grid, provided that the distribution of the sales revenue in a grid is statistically similar to the power law. We speculate that hub stores trigger exploration between different store types, and consequently, the sales volumes of highly diverse neighborhoods increase compared with those of less diverse neighborhoods. These results highlight the importance of urban diversity for economic prosperity, which can lead to an increased quality of life for city neighborhoods.

As is often believed that the more centrally located a shop, the higher its sales volume, this paper analyzed relationships between the spatial clustering of retail stores, their respective transaction volumes, and the urban street networks to determine whether, and to what extent, the accessibility and density of a store’s location was correlated with its transaction volume. While this hypothesis is widely accepted, its veracity is underexplored and rarely validated using large-scale empirical datasets, possibly owing to the lack of access. Therefore, transaction datasets and accessibility indicators were first examined; a clear, positive correlation between density and revenue was found for specialty stores wherein people do “comparison shopping,” and for stores that complemented each other for activities such as “one-trip shopping,” the revenues were positively correlated when the stores were clustered. Generally, daily-use stores’ revenues were more sensitive to local access and those of non-daily-use stores were more sensitive to global access. In conclusion, these findings would not have been found using conventional methodology focused on the retail sector as a whole, because aggregate market mechanisms would have hidden the observed effects on specific store categories. Therefore, upon disaggregating the data, we found a distinct heterogeneity across the different store types for what concerns the relationship between revenue and location.

The influence of the Internet of Things (IoT) and related produced data is destined to revolutionize economic and social society, even more incisively than the advent of digital. The creation of the IoT world would have been much more complicated if a big data structure had not been followed since the latter allows to analyze vast amounts of data. The IoT is the most significant flow of information collected on the Internet and, therefore, the largest supplier for big data systems, artificial intelligence (AI), and data science. Advanced statistical analysis techniques, neural networks, and AI algorithms, but also the ability to create mathematical models that best represent a physical phenomenon or social behavior, these are the new strategic assets in the digital transformation process that is facing the world of industry and services. In fact, collecting data is not enough: they must be managed, integrated, and compared with a mathematical model that formalizes the intrinsic knowledge in the experience and competence of people.

Commercial palm oil-derived biodiesel fuels (palm BDFs) were thoroughly profiled based on the specifications of international fuel standards. Their main components were found to be fatty acid methyl esters (FAME) with different numbers of double bonds in the fatty acid tails in addition to small amounts of unreactive glycerides and impurities, the concentrations of which varied slightly among the regional producers in Thailand. The fuel properties of the as-received commercial palm BDFs met international fuel standards; unfortunately, the fuel degraded significantly over time, presumably due to the presence of polyunsaturated fatty acid methyl esters (poly-FAME) and impurities. To prevent this degradation, the commercial palm BDFs were upgraded into partially hydrogenated fatty acid methyl esters with outstanding oxidation stability (H-FAME, a new type of biodiesel fuel enriched in monounsaturated fatty acid methyl esters (mono-FAME)) over supported Pd catalysts with metallic Pd nanoparticles as the catalytically active sites in a batch-type glass reactor under mild conditions (80 °C and 0.5 MPa H2). In the upgrading process, the unwanted component poly-FAME, which had low oxidation stability, was selectively converted into the target component, mono-FAME with high oxidation stability. Although the impurities in the commercial palm BDFs poisoned the supported Pd catalysts, particularly the sulfur species, the homemade mesoporous silica-supported Pd catalyst with a high Pd dispersion of 47% gave higher activity and tolerance to the impurities in the synthesis of palm H-FAMEs than the commercial alumina-supported Pd catalyst, which had a low Pd dispersion of 16%. In the accelerated oxidation stability test, the B20 fuels formulated by blending petro-diesel with the palm H-FAMEs with enhanced oxidation stability produced almost no deposits or sludges, whereas the fuels formulated by blending petro-diesel with commercial palm BDFs were seriously degraded and acidified, and formed deposits and sludges. Moreover, the palm H-FAMEs could be further purified by selective removal of the monoglycerides (MG) and steryl glucosides (SG) through wintering and adsorption posttreatments, and were determined to be a reliable BDF source with high safety and security for use in high blend fuels.

To improve the oxidative stability of biodiesel fuel (BDF), the polyunsaturated fatty acid methyl esters (poly-FAME) presented in commercial palm oil-derived biodiesel fuel (palm-BDF) were selectively hydrogenated to monounsaturated fatty acid methyl esters (mono-FAME) under a mild condition (80 °C, 0.5 MPa) using activated carbon (AC)-supported Pd catalysts with a Pd loading of 1 wt.%. The partially hydrotreated palm-BDF (denoted as H-FAME) which has low poly-FAME components is a new type of BDF with enhanced quality for use in high blends. In this study, we reported that the chemical states and particle sizes of Pd in the prepared Pd/AC catalysts were significantly influenced by the Pd precursors, Pd(NO3)2 and Pd(NH3)4Cl2, and thus varied their hydrogenation activity and product selectivity. The 1%Pd/AC (nit) catalyst, prepared using Pd(NO3)2, presented high performance for selective hydrogenation of poly-FAME into mono-FAME with high oxidation stability, owning to its large Pd particles (8.4 nm). Conversely, the 1%Pd/AC (amc) catalyst, prepared using Pd(NH3)4Cl2, contained small Pd particles (2.7 nm) with a little Cl residues, which could be completely removed by washing with an aqueous solution of 0.1 M NH4OH. The small Pd particles gave increased selectivity toward unwanted-FAME components, particularly the saturated fatty acid methyl esters during the hydrogenation of poly-FAME. This selectivity is unprofitable for improving the biodiesel quality.

Urban planning is undergoing a great shift from car-centric plans to pedestrian-centric ones. Although such movements are occurring worldwide, few attempts have been made to evaluate the urban structure quantitatively from the point of view of the pedestrian. This paper introduces local betweenness centrality and peak analysis as a method of network analysis, and applies them to 30 cities in Europe. We found both similarities and differences in the spatial patterns of local betweenness peaks among the cities: while the large-radius peaks in most cities appear along boulevards or streets with large traffic capacity, those with small-radius peaks vary between cities. This indicates that the areas favorable for pedestrians do not necessarily coincide with the historical center of the city, which has largely been created before the introduction of automobiles. Our findings are useful for urban planners and decisionmakers wishing to understand the current situation of the city and to make informed decisions.

Partial hydrogenation of soybean oil (SO)-derived biodiesel, as fatty acid methyl esters (FAMEs), over mesoporous palladium (Pd)/SBA-15 materials was examined in a semi-batch reactor. The amount of Pd/SBA-15 catalyst was varied from 0.5–1% by weight (wt%) of the SO feedstock. The selectivity of saturated FAMEs (C18:0), which contribute to an excellent oxidative stability but undesirable cold flow properties, over the Pd/SBA-15 catalyst at different wt% was poor after a 4-h reaction period. To improve the catalytic performance, zirconium (Zr) species were incorporated in the SBA-15, resulting in Zr-SBA-15 with tunable acidity and pore properties. Partial hydrogenation of SO-FAME over 0.75 wt% Pd/xZr-SBA-15 catalysts (where x is the Zr/silicon (Si) molar ratio and ranged from 0.01 to 0.11) was performed for 2 h. The catalytic performance and the selectivity towards trans-monounsaturated FAMEs (trans-C18:1), in terms of the turnover frequency (TOF) and trans-C18:1/cis-C18:1 ratio, respectively, were considered at 10% and 80% conversion levels of diunsaturated FAMEs (C18:2). The incorporation of Zr into SBA-15 resulted in an enhanced TOF due to the greater adsorption of both H2 and the basic double bonds of FAME molecules on the electron-deficient catalyst surfaces. The TOF for the Pd/xZr-SBA-15 catalysts increased as the Zr/Si molar ratio increased up to 0.07, and then slightly dropped at higher Zr/Si molar ratios, presumably due to the hindrance of adsorbed-reacted FAME molecules with strong adsorption and the worsening of physical properties, i.e. pore width (DP). The selectivity towards trans-C18:1 was directly correlated with the Zr/Si molar ratio. Since the strong adsorption of FAME molecules took place on the catalyst surface, the high level of trans-C18:1 was consequently generated. The oxidative stability of the partially hydrogenated biodiesels was improved by more than four-fold compared to that of the starting SO-FAMEs.

Palladium/silica (Pd/SiO2) and Pd–M/SiO2 catalysts, where M stands for sodium (Na), calcium (Ca) or barium (Ba), were studied for their catalytic ability in the partial hydrogenation of soybean oil...

MCM-41 has been hydrothermally synthesized using fumed silica (SiO2) and silatrane [Si(TEA)2] as silica sources. Pd nanoparticles were successfully impregnated to the mesoporous MCM-41 supports. Soybean oil methyl ester was partially hydrogenated by the Pd/MCM-41-SiO2 and Pd/MCM-41-silatrane catalysts under a mild condition (low temperature and pressure). Both catalysts could rapidly and selectively convert the polyunsaturated fatty acid methyl esters (C18:3 and C18:2) to monounsaturated fatty acid methyl esters (C18:1) at 100 °C and 0.4 MPa H2 within 4 h. The results verified that the Pd/MCM-41-silatrane catalyst with the greater surface of Pd active sites had higher catalytic activity, representing in term of turnover frequency (TOF), in partial hydrogenation than Pd/MCM-41-SiO2 under both C18:2 conversions of 40% and 60%. Even if the lower selectivity toward cis-C18:1 was obtained for the former. In addition to the better stable structure of MCM-41-silatrane support as compared to MCM-41-SiO2 support, silatrane precursor is more favorable to diminish the extent of complete hydrogenation than fumed silica as it provided the lower index. Even though, this silica precursor sues for more synthetic step. Due to the higher oxidative stability of Pd/MCM-41-SiO2, MCM-41-SiO2 support was further studied for the later research. When varying the Pd loadings in 0.5–2 wt.% on MCM-41-SiO2 support, the Pd(2)/MCM-41-SiO2 catalyst gave the highest performance (TOF) whether the complete hydrogenation was concurrently accompanied. Results signify that the nature of the silica source and the Pd concentration modified the surface active sites and size distribution of metallic particles, which determine the catalytic reactivity and selectivity.

This study analyzes the influence of pedestrianization of urban space on the revenues of surrounding retail stores. Pedestrianization refers to the conversion of street use from vehicles to a walkable environment. We compiled a unique transaction dataset containing the estimates of sales volumes for stores across Spain and combine it with data from Open Street Map to provide the history of land-use changes at the street-level. Based on these high-granular datasets, we apply a difference-in-differences empirical method to measure the economic impact of pedestrian intervention. The results show that stores located in pedestrian environments tend to record higher sales volumes than stores located in non-pedestrian environments. We further analyze the mechanisms underlying this revenue-boosting effect and find that a key factor is the store density of the pedestrianized place, while geographic location is insignificant. This finding suggests that there are no differentiation impacts on stores' revenue based on whether pedestrianization occurs in the city center or periphery. Store category also acts as an important moderator for revenue impacts, with positive effects observed mostly for the cafe or restaurant category. Our results provide suggestive evidence that people prefer a pedestrian-friendly environment to a vehicle-oriented one for non-tradable, local consumption activities. This research provides evidence-based policy implications for urban planners interested in making smart, sustainable cities.

Urban shrinking means a densely populated urban area or city where is experiencing a significant population loss. Currently studies have examined the relationship between built environment and socioeconomic attributes and urban shrinking, however ignore the local effects. Here, we show spatially heterogeneous associations of environment and socioeconomic attributes with urban shrinking reflected by the change of VIIRS night-time light radiance during the period 2014–2019 by mixed geographically weighted regression model, after variables screening by random forest. We found that during the period 2014–2019, there were 35 km2 in Yokohama was shrinking, with most of them being mixed-use land. In general, bus stop density (BSD), road intersection density (RID), aging population (PoAP), housing price (HP), distance to the nearest park (DNP), proportion of business areas (PoBA), and proportion of private houses and flats (PoH_ private) have mixed effects on urban shrinking. Furthermore, BSD, RID, PoAP, DNP and PoH_private have negative or positive association with urban shrinking across locations, suggesting spatial heterogeneous strategies should be considered to address urban shrinking. We anticipate our study to be a start point to use mixed GWR model in shrinking city and as additions in examining the relationship between built environment and socioeconomic attributes and population loss.

Partial hydrogenation of soybean oil-derived fatty acid methyl esters was studied using MCM-41 mesoporous silica-supported Pd-Pt bimetallic catalysts with tunable porosity under mild reaction conditions (100 °C, 0.4 MPa H2, 4 h). This process produced partially hydrogenated fatty acid methyl esters (H-FAME) as a new type of high-quality biodiesel fuel enriched in monounsaturated fatty acid methyl esters (mono-FAME), which is a potential source for formulating high blends of biodiesel fuel with petrodiesel. MCM-41 supports with various structural properties and morphologies were synthesized by self-assembly with different amounts of ammonia solution as a mineralizing agent. Bimetallic Pd-Pt nanoparticles with a Pd/Pt atomic ratio of 4 were stepwise impregnated on three MCM-41 supports, resulting in a series of Pd-Pt/MCM-41 bimetallic catalysts with tunable porosity (0.89–1.79 cm3 g−1), average pore size (3.2–8.5 nm), and particle size (0.12–0.62 μm). The Pd-Pt/MCM-41 catalyst prepared with the least amount of ammonia produced the best partial hydrogenation conversion of polyunsaturated FAME into mono-FAME, ascribed to nano-aggregation resulting in a dual-pore system containing large pores for fast molecular diffusion; a high turnover frequency (1920 h−1), larger k1 rate constant (0.60 gcat−1h−1), and smaller k2 rate constant (0.37 gcat−1h−1) were obtained. Furthermore, this Pd-Pt/MCM-41 catalyst exhibited excellent sulfur resistance in the synthesis of H-FAME, even though the feedstocks contained approximately 5 ppm of sulfur contaminates. These results demonstrate that the sulfur-resistant Pd-Pt/MCM-41 bimetallic catalysts with stable and dual pore system are beneficial for obtaining higher quality BDF to reduce our reliance on fossil fuels.

Zr-SBA-15 materials have been successfully synthesized using the direct synthesis method in self-generated acidic conditions. The diffuse reflectance UV-visible (DRUV-vis) spectra and X-ray photoelectron spectroscopy (XPS) results revealed that most of the zirconium species could be incorporated into silica framework. No agglomeration of Zr species was detected in the silica framework and at the extra-framework. Nevertheless, the continuous diminution of BET surface area, total pore volume, and pore width with increase in Zr/Si molar ratios was distinctly observed, which resulted from the deposition of some tiny and well-dispersed Zr species at the inner pore walls and/or external surface areas. The Zr incorporation also resulted in the augmentation of the microporous characteristics of all materials. The CO 2 adsorption measurement was performed under ambient conditions (25 °C and 1 bar) in order to meet the broad needs of industry and household. The largest amount of CO 2 uptake was demonstrated by 0.03 Zr-SBA-15 at around 0.68 mmol/g (29.92 mg/g). The CO 2 adsorption capability of these materials correlated considerably with their textural properties, particularly microporous volume (V Micro ).

The effect of the pore size of Pd/MCM-41 on the catalytic activity and selectivity in partial hydrogenation of canola-oil-derived biodiesel was studied under mild reaction conditions. The catalysts with different pore sizes were obtained by varying the amount of aqueous ammonia added during the synthesis: Pd/MCM-41-a8, Pd/MCM-41-a5, and Pd/MCM-41-a3 with average pore diameters of 3.72, 3.99, and 7.55 nm, respectively. The supports and supported Pd catalysts were characterized by Brunauer–Emmett–Teller surface area analysis, X-ray powder diffraction, transmission electron microscopy, CO pulse chemisorption, and temperature-programmed desorption of ammonia. The highest hydrogenation activity was found for the largest pore catalyst, Pd/MCM-41-a3, as presented in term of the turnover frequency (TOF), whereas Pd/MCM41-a8 and Pd/MCM-41-a5 provided higher selectivity toward cis-monounsaturated fatty acid methyl ester (FAME), which was attributed to their limited pore dimension. The correlation between the cataly...