Sequential Route Research Articles

Production of ethyl esters from forage radish seed: An integrated sequential route using pressurized ethanol and ethyl acetate

This work investigated the production of fatty acid ethyl esters (FAEE) from forage radish seeds using a sequential process with pressurized ethanol and ethyl acetate as solvents and acyl acceptors. First, the effect of the solvent on the extraction was determined and subsequently, the sequential reaction was carried out with the material from the pressurized liquid extraction (PLE) where the effects of temperature, residence time and water concentration were investigated. Conventional extraction was carried out for comparative purposes with regards to the oil quality of the PLE and its efficiency in the reaction. The use of ethanol resulted in a high mass yield, which was attributed to the high non-lipid fraction in the extracted material, and ethyl acetate retained proteins, phenolic compounds and sugars in the defatted meal. The main fatty acids in the oil were oleic and erucic acids and high levels of minority compounds were observed in the PLE oil. In the sequential reaction, supercritical ethyl acetate at 300 °C provided the highest FAEE content (42 wt% in 25 min). The addition of water in the acyl acceptor increased the production of FAEE, reduced the thermal degradation of the esters and provided a product with low levels of acylglycerols. Oils from PLE and conventional extraction showed similar performance in the synthesis of esters. Ethyl linolenate and ethyl linoleate were the esters that showed the highest level of degradation. The highest content of FAEE (53 wt%) was reached at 300 °C with 20% (v/v) of water, resulting in a triacetin content of 0.92 wt%.

Energy comparison of sequential and integrated CO2 capture and electrochemical conversion

Integrating carbon dioxide (CO2) electrolysis with CO2 capture provides exciting new opportunities for energy reductions by simultaneously removing the energy-demanding regeneration step in CO2 capture and avoiding critical issues faced by CO2 gas-fed electrolysers. However, understanding the potential energy advantages of an integrated process is not straightforward due to the interconnected processes which require knowledge of both capture and electrochemical conversion processes. Here, we identify the upper limits of the integrated process from an energy perspective by comparing the working principles and performance of integrated and sequential approaches. Our high-level energy analyses unveil that an integrated electrolyser must show similar performance to the gas-fed electrolyser to ensure an energy benefit of up to 44% versus the sequential route. However, such energy benefits diminish if future gas-fed electrolysers resolve the CO2 utilisation issue and if an integrated electrolyser shows lower conversion efficiencies than the gas-fed system.

Cyclocarbonylation of Allenyl Glyoxylate Strategy to Build the Tricyclic Core of Cyclocalopin A.

An approach for the construction of the tricyclic framework of naturally occurring cyclocalopin A is described. The establishment of the crucial intermediate α-methylene bis-γ,δ-lactone involves a [2 + 2 + 1]-cyclocarbonylation of newly introduced allenyl glyoxylate via direct methods using Mo(CO)6 or sequential reaction pathways. The sequential reaction route involved a stannylative cyclization by Pd(0) catalyst, bromination of an vinyl stannane moiety, and final cyclocarbonylation by palladium catalysis to provide the bis-γ,δ-lactone. The feasibility of forming the spiro-system by an exo-selective [4 + 2]-cycloaddition was accomplished.

The vehicle routing problem of intercity ride-sharing between two cities

In this paper, we consider that a private company has developed a platform to provide intercity ride-sharing (IRS) services for riders between two cities. The riders between the two cities need to provide their travel information to the platform hours in advance. The company adopts commercial vehicles to pick up riders from one city and deliver them to the other city. The vehicle routing problem of IRS (VRP-IRS) is one of the core problems in the platform's decision making process. Due to the private nature of IRS platform, it is assumed that the platform aims to maximize the total profit of the IRS system by optimizing vehicle routing. As the IRS is long-distance travel, in order to ensure driving safety, each driver has to take a break after completing a long-distance trip. In this paper, the VRP-IRS is defined on a directed graph and formulated as a mixed integer linear programming problem. As the VRP-IRS is NP-hard, we propose a variable neighborhood search algorithm to solve the VRP-IRS. According to the characteristics of the feasible solutions to the VRP-IRS, a greedy sequential route construction method is developed to generate the initial solutions. Four trip-based neighborhood operators and four rider-based local search operators are proposed to shake the current solution to a new neighborhood and find better solutions based on the new neighborhood, respectively. Finally, numerical examples are provided to illustrate the performance of the proposed algorithm and the properties of the proposed model.

A Modified Sequential Deposition Route for High-Performance Carbon-Based Perovskite Solar Cells under Atmosphere Condition.

Carbon-based hole transport material (HTM)-free perovskite solar cells have exhibited a promising commercialization prospect, attributed to their outstanding stability and low manufacturing cost. However, the serious charge recombination at the interface of the carbon counter electrode and titanium dioxide (TiO2) suppresses the improvement in the carbon-based perovskite solar cells’ performance. Here, we propose a modified sequential deposition process in air, which introduces a mixed solvent to improve the morphology of lead iodide (PbI2) film. Combined with ethanol treatment, the preferred crystallization orientation of the PbI2 film is generated. This new deposition strategy can prepare a thick and compact methylammonium lead halide (MAPbI3) film under high-humidity conditions, which acts as a natural active layer that separates the carbon counter electrode and TiO2. Meanwhile, the modified sequential deposition method provides a simple way to facilitate the conversion of the ultrathick PbI2 capping layer to MAPbI3, as the light absorption layer. By adjusting the thickness of the MAPbI3 capping layer, we achieved a power conversation efficiency (PCE) of 12.5% for the carbon-based perovskite solar cells.

Fluorescent annulated imidazo[4,5-c]isoquinolines via a GBB-3CR/imidoylation sequence - DNA-interactions in pUC-19 gel electrophoresis mobility shift assay.

Herein we report the development of a sequential synthesis route towards annulated imidazo[4,5-c]isoquinolines comprising a GBB-3CR, followed by an intramolecular imidoylative cyclisation. X-Ray crystallography revealed a flat 3D structure of the obtained polyheterocycles. Thus, we evaluated their interactions with double-stranded DNA by establishing a pUC-19 plasmid-based gel electrophoresis mobility shift assay, revealing a stabilising effect on ds-DNA against strand-break inducing conditions.

Investigating the Sequential Deposition Route for Mixed Cation Mixed Halide Wide Bandgap Perovskite Absorber Layer

Wide bandgap (Eg) perovskite solar cells (PSCs) are emerging as the preferred choice for top cells in a tandem architecture with crystalline silicon solar cells. Among the wide bandgap perovskites, a mixed cation mixed halide composition containing CsyFA1-yPbI3−xBrx is a popular choice because the presence of bromine widens the bandgap and addition of cesium stabilizes the crystal structure. These perovskite layers are commonly fabricated using one-step spin coating technique; however, sequential spin coating followed by dip coating has been successful in offering better control over the crystallization process for low bandgap absorber layers. In this paper, the fabrication of a Cs0.2FA0.8PbI3−xBrx perovskite absorber layer using the sequential deposition route is reported. The concentration of bromine was varied in the range 0 ≤ x ≤ 1 and optical, structural, and morphological properties of the films were studied. As the concentration was increased, the perovskite showed better crystallinity and the presence of large grains with high surface roughness, indicating the formation of the CsPbBr3 phase. Optically, the perovskite films exhibited higher absorbance in the ultraviolet (UV) range between 300 and 500 nm, hence up to x = 0.3 they can be profitably employed as a wide bandgap photon absorber layer in solar cell applications.

Sequential Post-Polymerization Modification of Aldehyde Polymers to Ketone and Oxime Polymers.

A new sequential post-polymerization modification route has been developed for the synthesis of multifunctional polymers from a simple aldehyde polymer. In the first modification step, a template polymer derived from the radical polymerization of 4-vinyl benzaldehyde undergoes Rh-catalyzed hydroacylation with alkenes to furnish a group of ketone polymers. In the second modification step, Schiff base formation with alkoxy ammonium salts introduces a second group-an oxime functionality. Both the steps are highly efficient, introducing evenly distributed dual functionalities at the same position.

Perovskite Quantum Dots Encapsulated in a Mesoporous Metal–Organic Framework as Synergistic Photocathode Materials

Metal halide perovskite quantum dots, with high light-absorption coefficients and tunable electronic properties, have been widely studied as optoelectronic materials, but their applications in photocatalysis are hindered by their insufficient stability because of the oxidation and agglomeration under light, heat, and atmospheric conditions. To address this challenge, herein, we encapsulated CsPbBr3 nanocrystals into a stable iron-based metal-organic framework (MOF) with mesoporous cages (∼5.5 and 4.2 nm) via a sequential deposition route to obtain a perovskite-MOF composite material, CsPbBr3@PCN-333(Fe), in which CsPbBr3 nanocrystals were stabilized from aggregation or leaching by the confinement effect of MOF cages. The monodispersed CsPbBr3 nanocrystals (4-5 nm) within the MOF lattice were directly observed by transmission electron microscopy and corresponding mapping analysis and further confirmed by powder X-ray diffraction, infrared spectroscopy, and N2 adsorption characterizations. Density functional theory calculations further suggested a significant interfacial charge transfer from CsPbBr3 quantum dots to PCN-333(Fe), which is ideal for photocatalysis. The CsPbBr3@PCN-333(Fe) composite exhibited excellent and stable oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities in aprotic systems. Furthermore, CsPbBr3@PCN-333(Fe) composite worked as the synergistic photocathode in the photoassisted Li-O2 battery, where CsPbBr3 and PCN-333(Fe) acted as optical antennas and ORR/OER catalytic sites, respectively. The CsPbBr3@PCN-333(Fe) photocathode showed lower overpotential and better cycling stability compared to CsPbBr3 nanocrystals or PCN-333(Fe), highlighting the synergy between CsPbBr3 and PCN-333(Fe) in the composite.

A sequential route of data and document qualities, satisfaction and motivations on researchers' data reuse intentions

PurposeThis study examined how the qualities of both data and documents of existing datasets can contribute to researchers' satisfaction of data reuse, and how it affects their data reuse intentions mediated by attitudinal and normative beliefs of data reuse.Design/methodology/approachA combined theoretical framework integrating IS (Information Systems) Success Model and the Theory of Planned Behavior (TPB) was utilized to develop the research model of researchers' data reuse, which was evaluated using structural equation modeling based on 820 survey responses from STEM disciplines in the US.FindingsThis study found that both data and document qualities significantly contribute to researchers' satisfaction of data reuse. Then, their satisfaction significantly increases perceived usefulness and subjective norm of data reuse, and it decreases perceived risk associated with data reuse. Finally, both perceived usefulness and subjective norm significantly increases their data reuse intentions.Research limitations/implicationsThe combined theoretical framework integrating IS success model and TPB provides a new theoretical lens in understanding researchers' data reuse behaviors affected by the qualities of both data and documents.Practical implicationsThe findings of this study provided several practical implications in promoting and facilitating researchers' data reuse behaviors by improving data and document qualities of existing datasets.Originality/valueThis is one of the initial studies focusing on the roles of data and document qualities in researchers' data reuse, and it provides a systematic view of how data and document qualities influence researchers' data reuse mediated by their satisfaction of data reuse and attitudinal and normative beliefs.

Mechanistic Investigations into the Catalytic Levulinic Acid Hydrogenation, Insight in H/D Exchange Pathways, and a Synthetic Route to d8-γ-Valerolactone

γ-Valerolactone (GVL) is readily accessible by catalytic hydrogenation of carbohydrate-derived levulinic acid (LA) and is an attractive biobased chemical with a wide range of applications in both the chemical (e.g., as biomass-derived solvent) and the transportation fuel sector. In this study, we used isotopic labeling experiments to provide insights into the catalytic hydrogenation pathways involved in the conversion of LA to GVL under different reaction conditions using water as an environmentally benign solvent and Ru/C as a readily available catalyst. 2H NMR experiments combined with quantum chemical calculations revealed that deuterium atoms can be incorporated at different positions as well as the involvement of the different intermediates 4-hydroxypentanoic acid and α-angelica lactone (α-AL). The insight provided by these studies revealed an as of yet unexploited sequential deuteration route to synthesize fully deuterated LA and GVL. The route starts by the conversion of LA to α-AL followed by a selective deuteration of the acidic protons of α-AL by H/D exchange with D2O. Subsequent ring-opening in D2O (d2-AL to d3-LA) and exchange of the remaining protons of d3-LA via a keto-enol tautomerization by heating in D2O under acidic conditions gives d8-LA. Finally, the d8-LA is catalytically reduced at low temperature using Ru/C with D2 in D2O to d8-GVL.

Path Planning Optimization for Agricultural Spraying Robots Using Hybrid Dragonfly – Cuckoo Search Algorithm

Finding collision-free paths and optimized path coverage over an agricultural landscape has been a critical research problem among scientists and researchers over the years. Key precision farming strategies such as seeding, spraying fertilizers, and harvesting require special path planning techniques for efficient operations and will directly influence reducing the running cost of the farm. The main objective of this research work is to generate an optimized sequential route in an agricultural landscape with the nominal distance. In this proposed work, a novel Hybrid Dragonfly – Cuckoo Search algorithm is proposed and implemented to generate the sequential route for achieving spraying applications in greenhouse environments. Here the agricultural routing problem is expressed as a Travelling Salesman Problem, and the simulations are performed to find the effectiveness of the proposed algorithm. The proposed algorithm has generated better results when compared with other computational techniques such as PSO in terms of both solution quality and computational efficiency.

The Role of Gender and Familiarity in a Modified Version of the Almeria Boxes Room Spatial Task.

Individual factors like gender and familiarity can affect the kind of environmental representation that a person acquires during spatial navigation. Men seem to prefer relying on map-like survey representations, while women prefer using sequential route representations. Moreover, a good familiarity with the environment allows more complete environmental representations. This study was aimed at investigating gender differences in two different object-position learning tasks (i.e., Almeria Boxes Tasks) assuming a route or a survey perspective also considering the role of environmental familiarity. Two groups of participants had to learn the position of boxes placed in a virtual room. Participants had several trials, so that familiarity with the environment could increase. In both tasks, the effects of gender and familiarity were found, and only in the route perspective did an interaction effect emerge. This suggests that gender differences can be found regardless of the perspective taken, with men outperforming women in navigational tasks. However, in the route task, gender differences appeared only at the initial phase of learning, when the environment was unexplored, and disappeared when familiarity with the environment increased. This is consistent with studies showing that familiarity can mitigate gender differences in spatial tasks, especially in more complex ones.

Celebrating Professor Barry M. Trost's 80th Birthday

Celebrating Professor Barry M. Trost's 80^th Birthday

On the effect of Mn-content on the strength-ductility balance in Ni-free high N transformation induced plasticity steels

The present work deals with the room temperature microstructure-mechanical properties relationship in Ni-free high N transformation induced plasticity steels. The tensile properties of the alloy with lower Mn content of 4%, and thus lower austenite fraction and austenite stability, was mainly controlled through sequential (extended) transformation route of γ→ε→α′. The extended route resulted in a higher strain hardening rate and lower ductility value. In addition, the formation of thermally-induced martensite before plastic deformation reduced the capacity of strain partitioning and load transition between the austenite and ferrite. In contrast, the tensile properties of the alloy holding higher Mn content of 8% with higher austenite fraction and stability was mainly governed by twin-aided transformation route of γ→γtwinned→α′. It was found that the higher strain compatibility between austenite and ferrite resulted in a substantially high uniform elongation and moderate strain hardening rate.

Modelling the contribution that different sexual practices involving the oropharynx and saliva have on Neisseria gonorrhoeae infections at multiple anatomical sites in men who have sex with men

BackgroundThe spectrum of sexual practices that transmit Neisseria gonorrhoeae in men who have sex with men (MSM) is controversial. No studies have modelled potential Neisseria gonorrhoeae transmission when one sexual...

Sputtered Ag-alloyed Cu(In, Ga)(Se, S)2 solar cells by sequential process

A sequential route for low-cost fabrication of high quality Ag-alloyed CIGS absorbers is reported. Ag-alloying is introduced into the CuInGa precursor to widen the band gap and improve the crystallinity of the ACIGS absorbers. The morphological, compositional, and structural characteristics of the ACIGS absorber are also systematically investigated. Different Ag thin layer incorporation locations at the bottom, in the middle and on the top of CuInGa precursors are schemed for deep understanding the band gap energy and crystallinity regulation mechanism of Ag alloying. A conversion efficiency of 10.2% is achieved for the ACIGS device with Ag at the bottom. The notable Voc improvement can be obtained due to the widened band gap and the band gap gradient in the absorber created by the Ag and Ga elements grading. Finally, the ACIGS absorbers are further sulfurized and a highest power conversion efficiency of 13.01% is obtained. Our results indicate that the sequential magnetron sputtering is a promising way for the fabrication of CIGS thin film solar cells.

A sustainable solvent system for processing CsPbBr3 films for solar cells via an anomalous sequential deposition route

Full covered CsPbBr3 films are prepared by using green solvents via an anomalous sequential deposition route.

An expeditious microwave assisted one-pot sequential route to pyrido fused imidazo[4,5-c] quinolines in green media

A novel one-pot sequential route for the synthesis of pyrido[2′,1′:2,3]imidazo[4,5-c]quinolines via microwave-assisted sequential reaction of 2-aminopyridines, 2-bromophenacyl bromides, and aldehydes has been developed in green media.

Multi-objective Route Planning for Underwater Cleaning Robot in Water Reservoir Tank

Underwater tank cleaning using robotic method is very crucial due to the concern on the diver’s safety in undisrupted water supply operation. A Remotely Operated Underwater Vehicles (ROV) used in the tank cleaning operation however, suffers from a high operational cost due to the lack of systematic operator guidance in robot maneuvering. This paper presents a multi-objective approach in designing a Decision Support System (DSS) for underwater cleaning robot. To explore all feasible path, the path alternatives for every cleaning point in the tank is found using Probabilistic Roadmap (PRM). Then, an optimized sequential route are identified using Non-Dominated Sorting Genetic Algorithm using Reference Point Based (NSGA-III). Several objectives such as path length and routing angle are considered to be optimized, while ensuring constraints such as similar deployment point, maximum daily time limit and cable entanglement. To measure the quality of the proposed solution, comparisons have been done based on performance of NSGA-III with Non-Dominated Sorting Genetic Algorithm II (NSGA-II) and Multi-Objective Particle Swarm Optimization (MOPSO) by considering the C-Metric value, execution time and estimated cleaning duration. In addition, comparisons with conventional path by human operator is also conducted to validate the significance of DSS application in underwater tank cleaning. Results have shown that NSGA-III has superiorities with an improvement of 11.11% in cleaning time as compared to NSGA-II and 5.12% improvement compared to MOPSO.