Identification of particulate matter sources on an hourly time-scale in a wood burning community

Particulate matter (PM) sources at two different sites in a rural town in New Zealand were investigated on an hourly time-scale. Streaker samplers were used to collect hourly, size-segregated PM(10-2.5) and PM(2.5) samples that were analyzed for elemental content using ion beam analysis techniques. Black carbon concentrations were determined using light reflection and PM(10) concentrations were recorded using colocated continuous PM monitors. PM(10) concentrations at both sites displayed a diurnal pattern, with hourly PM(10) concentration maxima in the evening (7 pm-midnight) and in the morning (7-9 am). One of the monitoring sites experienced consistently higher average PM(10) concentrations during every hour and analysis indicated that katabatic flows across the urban area contributed to the increased concentrations observed. Source apportionment using positive matrix factorization on the hourly data revealed four primary PM(10) sources for each site: biomass burning, motor vehicles, marine aerosol and crustal matter. Biomass burning was the most dominant source at both sites and was responsible for both the evening and morning PM(10) concentration peaks. The use of elemental speciation combined with PM(10) concentrations for source apportionment on an hourly time-scale has never been reported and provides unique and useful information on PM sources for air quality management.     

Wall coating behavior of catalyst slurries in non-porous ceramic microstructures

We report the use of the gas-displacement technique to generate wall coatings of catalyst slurries in fused silica capillaries, as well as ceramic microreactors. The non-porous and glassy surfaces make it difficult to prepare adherent coatings within ceramic structures. In the fused silica capillaries, we were able to show adherent catalyst coats up to thick and found that the maximum fraction coated decreased as the capillary diameter decreased. We developed a model for the various diameters showing the relationship of the fraction coated versus the capillary number, Ca. It was determined that the coating behavior was controlled by the coupled effects of the fluid rheology and the dramatic increase in the Reynold's number as the diameters decreased. For the ceramic microreactor, we determined that the coatings were adherent and tests showed the wall-coated catalyst in these structures to be catalytically active for the steam reforming of methanol.     

Glycemic responses to sweetened dried and raw cranberries in humans with type 2 diabetes

This study assessed the metabolic response to sweetened dried cranberries (SDC), raw cranberries (RC), and white bread (WB) in humans with type 2 diabetes. Development of palatable cranberry preparations associated with lower glycemic responses may be useful for improving fruit consumption and glycemic control among those with diabetes. In this trial, type 2 diabetics (n= 13) received WB (57 g, 160 cal, 1 g fiber), RC (55 g, 21 cal, 1 g fiber), SDC (40 g, 138 cal, 2.1 g fiber), and SDC containing less sugar (SDC-LS, 40 g, 113 cal, 1.8 g fiber + 10 g polydextrose). Plasma glucose (mmol/L) peaked significantly at 60 min for WB, and at 30 min for RC, SDC, and SDC-LS at 9.6 ± 0.4, 7.0 ± 0.4, 9.6 ± 0.5, and 8.7 ± 0.5, respectively, WB remained significantly elevated from the other treatments at 120 min. Plasma insulin (pmol/mL) peaked at 60 min for WB and SDC and at 30 min for RC and SDC-LS at 157 ± 15, 142 ± 27, 61 ± 8, and 97 ± 11, respectively. Plasma insulin for SDC-LS was significantly lower at 60 min than either WB or SDC. Insulin area under the curve (AUC) values for RC and SDC-LS were both significantly lower than WB or SDC. Phenolic content of SDC and SDC-LS was determined following extraction with 80% acetone prior to high-performance liquid chromatography (HPLC) and electronspray ionization-mass spectrometry (ESI-MS) and found to be rich in 5-caffeoylquinic cid, quercetin-3-galactoside, and quercetin-3-galactoside, and the proanthocyanidin dimer epicatechin. In conclusion, SDC-LS was associated with a favorable glycemic and insulinemic response in type 2 diabetics. Practical Application: This study compares phenolic content and glycemic responses among different cranberry products. The study seeks to expand the palatable and portable healthy food choices for persons with type 2 diabetes. The novel use of polydextrose as a bulking agent making possible a reduction in caloric content and potential glycemic response is also characterized in this study.     

Greywater reuse for irrigation: Effect on soil properties

A controlled study of the effect of greywater (GW) irrigation on soil properties was conducted. Containers of sand, loam and loess soils were planted with lettuce, and irrigated with fresh water, raw artificial GW or treated artificial GW. Greywater was treated using a recirculating vertical-flow constructed wetland. Soil samples were collected every 10 days for the 40-day duration of the study, and plant growth was measured. Soils were analysed for physicochemical and biological parameters to determine changes caused by the different treatments. It was demonstrated that raw artificial GW significantly increased the development of hydrophobicity in the sand and loam soils, as determined by water droplet penetration time. No significant changes were observed for the loess soil under all treatments. Observed hydrophobicity was correlated with increased oil and grease and surfactant concentrations in the soil. Zeta (ζ) potential of the soils was measured to determine changes in the soil particle surface properties as a result of GW irrigation. A significant change in ζ-potential (less negative) was observed in the raw artificial GW-irrigated sand, whereas no difference was observed in the loam or loess. Soils irrigated with fresh water or treated GW exhibited no increase in hydrophobicity. Fecal coliform bacteria were absent or < 10 CFU g^− 1 in soils irrigated with fresh water or treated GW, but at least 1 order of magnitude higher in raw artificial GW irrigated soils. Only in the last sampling event and only for the loess soil was plant growth significantly higher for fresh water irrigated vs. raw or treated GW irrigated soils. This study demonstrates that treated GW can be effectively irrigated without detrimental effects on soil or plant growth; however, raw GW may significantly change soil properties that can impact the movement of water in soil and the transport of contaminants in the vadose zone.     

Modeling the limitations and implicit costs of cereal self-sufficiency: the case of Morocco

High and volatile food prices in 2008 have led to renewed interest in national food security, particularly in the Arab world. One often discussed strategy is to reduce import dependency by increasing self-sufficiency. An alternative strategy is agricultural self-reliance, where revenues from export crops are sufficient to cover the costs of food imports. For countries with limited land and water resources and a comparative advantage in producing export crops rather than cereals, self-reliance (achieving food security through trade) may be more effective than aiming for self-sufficiency in cereals. This paper uses a simple model based on a production possibilities frontier to demonstrate the limitations and high costs of achieving self-sufficiency in cereals for Morocco. At current yield levels, Morocco is capable of achieving 85% self-sufficiency. With a 30% increase in yields the country could achieve self-sufficiency in the present, and with a 40% increase, achieve self-sufficiency until 2022. However, this would require land to be diverted from high value crops to cereals, with an opportunity cost exceeding US$10.3 billion in gross revenue during the period 2008–2022. Morocco and other Arab countries should consider these factors when they asses whether self-sufficiency is a reasonable policy objective, or whether self-reliance would be more appropriate. The model requires only very basic data, uses a simple maximization routine, and can be easily replicated in a wide variety of contexts.     

A Dynamic Route Choice Model Considering Uncertain Capacities

Abstract: The standard assumption in (dynamic) traffic assignment models is that route choice is solely determined by a (perceived) deterministic travel time. However, recently, there is a growing interest in (dynamic) equilibrium route choice models in which travelers not only select their paths based on an estimated deterministic travel time, but also based on travel time reliability, in this article defined as the probability that the actual travel time deviates from the anticipated value. We extend the linear programming cell transmission model‐based dynamic traffic assignment (LP CTM‐DTA) model to account for travelers’ consideration of uncertainty regarding saturation flow rates (in this article referred to as capacities). It is shown that these reliability considerations can be accounted for by simply reducing the road capacities appearing in the constraint set of the classical LP CTM‐DTA model. More importantly, we provide results on the amount of capacity reduction necessary to ensure a certain reliability level. Although in the proposed model any probability distribution can be used to model the uncertainty, the selection of a specific probability distribution can potentially be burdensome for the modeler. To this end, we also present results on the class of symmetric probability distributions that has been particularly popular in the robust optimization literature. Properties for this broad class of distributions will be derived within the context of the introduced model. In numerical case studies, the model predicts that travel patterns can be significantly different when accounting for travelers’ reliability considerations.     

Fe3O4@mesoporouspolyaniline: A Highly Efficient and Magnetically Separable Catalyst for Cross‐Coupling of Aryl Chlorides and Phenols

A high surface, magnetic Fe₃O₄@mesoporouspolyaniline core‐shell nanocomposite was synthesized from magnetic iron oxide (Fe₃O₄) nanoparticles and mesoporouspolyaniline (mPANI). The novel porous magnetic Fe₃O₄ was obtained by solvothermal method under sealed pressure reactor at high temperature to achieve high surface area. The mesoporouspolyaniline shell was synthesized by in situ surface polymerization onto porous magnetic Fe₃O₄ in the presence of polyvinylpyrrolidone (PVP) and sodium dodecylbenzenesulfonate (SDBS), as a linker and structure‐directing agent, through ‘blackberry nanostructures’ assembly. The material composition, stoichiometric ratio and reaction conditions play vital roles in the synthesis of these nanostructures as confirmed by variety of characterization techniques. The role of the mesoporouspolyaniline shell is to stabilize the porous magnetic Fe₃O₄ nanoparticles, and provide direct access to the core Fe₃O₄ nanoparticles. The catalytic activity of magnetic Fe₃O₄@mesoporousPANI nanocomposite was evaluated in the cross‐coupling of aryl chlorides and phenols.     

Assaying small-molecule-receptor interactions by continuous flow competitive displacement chromatography/mass spectrometry

Small-molecule screening techniques that employ mass spectrometry detection have been highly successful. However, the inability of conventional techniques, such as frontal affinity chromatography-mass spectrometry (FAC-MS), to easily identify weak binding molecules (i.e., Kd >or= 1 microM) using small amounts of target protein (subpicomole levels) represents a significant impediment to the widespread use of the method in the routine screening of low-abundance membrane receptors. This limitation is particularly notable in the early stages of the drug discovery process, as weak binding molecules can serve as useful leads for targets with no known ligand or when existing tight binding ligands have little therapeutic value. Competitive assay methods involving the displacement of an indicator ligand offer a more sensitive alternative, as the ability to generate an appreciable signal through various methods, including transient overconcentrations of indicator compounds, provides an unambiguous means for identifying weak affinity ligands. In this work we describe a continuous flow competitive assay based on the principles of FAC-MS that can be widely used to identify and characterize weak affinity ligands using low levels of the nicotinic acetylcholine receptor from Torpedo californica (nAChR). The validity of the assay is shown through the ability to identify nicotine (Kd approximately 1 microM) with columns containing <2 pmol of binding sites. Multiple injections of nicotine on a single column produce reproducible peaks in the signal of the indicator compound, epibatidine (Kd approximately 2 nM) showing minimal degradation in signal intensity between trials. The intensity of the peaks is dependent on the concentration of nicotine being injected, and binding curves can be generated through multiple injections on the same column. We investigate and optimize various parameters, including assay speed and concentrations, and demonstrate an automated assay format with the potential for use as a high-throughput screening tool. The ability to screen for weak binders of more pharmacologically relevant membrane receptors in a high-throughput screening format is discussed.     

Modeling,equilibrium, and demand management for mobility and delivery services in Mobility-as-a-Service ecosystems

Mobility-as-a-Service (MaaS) is an emerging business model integrating various travel modes into a single mobility service accessible on demand. Besides the on-demand mobility services, instant delivery services have increased rapidly and particularly boomed during the coronavirus (COVID-19) pandemic, requiring online orders to be delivered timely. In this study, to deal with the redundant mobility resources and high costs of instant delivery services, we model an MaaS ecosystem that provides mobility and instant delivery services by sharing the same multimodal transport system. We derive a two-class bundle choice user equilibrium (BUE) for mobility and delivery users in the MaaS ecosystems. We propose a bilateral surcharge–reward scheme (BSRS) to manage the integrated mobility and delivery demand in different incentive scenarios. We further formulate a bilevel programming problem to optimize the proposed BSRS, where the upper level problem aims to minimize the total system equilibrium costs of mobility and delivery users, and the lower level problem is the derived two-class BUE with BSRS. We analyze the optimal operational strategies of the BSRS and develop a solution algorithm for the proposed bilevel programming problem based on the system performance under BSRS. Numerical studies conducted with real-world data validate the theoretical analysis, highlight the computational efficiency of the proposed algorithm, and indicate the benefits of the BSRS in managing the integrated mobility and delivery demand and reducing total system equilibrium costs of the MaaS ecosystems.