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Abstract. The impact of multiphase reactions involving nitrogen dioxide (NO2) and aromatic compounds was simulated in this study. A mechanism (CAPRAM 2.4, MODAC Mechanism) was applied for the aqueous phase reactions, whereas RACM was applied for the gas phase chemistry. Liquid droplets were considered as monodispersed with a mean radius of 0.1 µm and a liquid content (LC) of 50 µg m-3. The multiphase mechanism has been further extended to the chemistry of aromatics, i.e. reactions involving benzene, toluene, xylene, phenol and cresol have been added. In addition, reaction of NO2 with dissociated hydroxyl substituted aromatic compounds has also been implemented. These reactions proceed through charge exchange leading to nitrite ions and therefore to nitrous acid formation. The strength of this source was explored under urban polluted conditions. It was shown that it may increase gas phase HONO levels under some conditions and that the extent of this effect is strongly pH dependent. Especially under moderate acidic conditions (i.e. pH above 4) this source may represent more than 75% of the total HONO/NO2 - production rate, but this contribution drops down close to zero in acidic droplets (as those often encountered in urban environments).

<p>This paper presents cuckoo search algorithm (CSA) for solving non-convex economic load dispatch (ELD) problems of fossil fuel fired generators considering transmission losses and valve point loading effect. CSA is a new meta-heuristic optimisation technique inspired from the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of other host birds of other species. The strength of the proposed meta-heuristic optimization technique CSA has been tested and validated on the standard IEEE 14-bus, 26-bus and 30-bus system with several heuristic load patterns. The results have indicated that the proposed approach is able to obtain significant economic load dispatch solutions than those of Firefly Algorithm (FFA) and other soft computing techniques reported in the literature.</p>

AbstractSolar fuels offer a promising approach to provide sustainable fuels by harnessing sunlight1,2. Following a decade of advancement, Cu2O photocathodes are capable of delivering a performance comparable to that of photoelectrodes with established photovoltaic materials3–5. However, considerable bulk charge carrier recombination that is poorly understood still limits further advances in performance6. Here we demonstrate performance of Cu2O photocathodes beyond the state-of-the-art by exploiting a new conceptual understanding of carrier recombination and transport in single-crystal Cu2O thin films. Using ambient liquid-phase epitaxy, we present a new method to grow single-crystal Cu2O samples with three crystal orientations. Broadband femtosecond transient reflection spectroscopy measurements were used to quantify anisotropic optoelectronic properties, through which the carrier mobility along the [111] direction was found to be an order of magnitude higher than those along other orientations. Driven by these findings, we developed a polycrystalline Cu2O photocathode with an extraordinarily pure (111) orientation and (111) terminating facets using a simple and low-cost method, which delivers 7 mA cm−2 current density (more than 70% improvement compared to that of state-of-the-art electrodeposited devices) at 0.5 V versus a reversible hydrogen electrode under air mass 1.5 G illumination, and stable operation over at least 120 h.

United Nation’s sustainable goals place emphasis on renewable energy resources to transform the world into a sustainable one and enable it to have affordable energy. Of late alternative green fuels are becoming promising sources of fuel to address the energy crisis. Waste cooking oil (WCO) is the raw material used for biodiesel preparation, which can be employed as a fuel in compression ignition (CI) engines. This article investigates the dual impact of biodiesel, a green fuel and a renewable green additive (turpentine oil) on the performance and emissions of a CI engine. The studies were performed using a B20 (20% biodiesel + 80% diesel) WCO biodiesel fuel blend with 2.5% and 5% vol. of turpentine oil as an additive. The outcome of this research showed an improvement in brake thermal efficiency for the B20 biodiesel blend with a 5% turpentine oil additive. Turpentine oil additive promoted more complete combustion and produced lower carbon monoxide (CO), hydrocarbon (HC) and smoke emissions. However, the oxides of nitrogen (NOx) emissions increased as the turpentine oil composition increased from 2.5% to 5%, which is 4.5% more than B20. The outcome of this study can be extended to accomplish the objectives of sustainable development goal 7 (affordable and clean energy) and goal 13 (climate action) which are planned to be achieved by 2030.

This study evaluated the efficacy of enzyme induced calcite precipitation (EICP) in restricting the mobility of heavy metals in soils. EICP is an environmentally friendly method that has wide ranging applications in the sustainable development of civil infrastructure. The study examined the desorption of three heavy metals from treated and untreated soils using ethylene diamine tetra-acetic acid (EDTA) and citric acid (C6H8O7) extractants under harsh conditions. Two natural soils spiked with cadmium (Cd), nickel (Ni), and lead (Pb) were studied in this research. The soils were treated with three types of enzyme solutions (ESs) to achieve EICP. A combination of urea of one molarity (M), 0.67 M calcium chloride, and urease enzyme (3 g/L) was mixed in deionized (DI) water to prepare enzyme solution 1 (ES1); non-fat milk powder (4 g/L) was added to ES1 to prepare enzyme solution 2 (ES2); and 0.37 M urea, 0.25 M calcium chloride, 0.85 g/L urease enzyme, and 4 g/L non-fat milk powder were mixed in DI water to prepare enzyme solution 3 (ES3). Ni, Cd, and Pb were added with load ratios of 50 and 100 mg/kg to both untreated and treated soils to study the effect of EICP on desorption rates of the heavy metals from soil. Desorption studies were performed after a curing period of 40 days. The curing period started after the soil samples were spiked with heavy metals. Soils treated with ESs were spiked with heavy metals after a curing period of 21 days and then further cured for 40 days. The amount of CaCO3 precipitated in the soil by the ESs was quantified using a gravimetric acid digestion test, which related the desorption of heavy metals to the amount of precipitated CaCO3. The order of desorption was as follows: Cd > Ni > Pb. It was observed that the average maximum removal efficiency of the untreated soil samples (irrespective of the load ratio and contaminants) was approximately 48% when extracted by EDTA and 46% when extracted by citric acid. The soil samples treated with ES2 exhibited average maximum removal efficiencies of 19% and 10% when extracted by EDTA and citric acid, respectively. It was observed that ES2 precipitated a maximum amount of calcium carbonate (CaCO3) when compared to ES1 and ES3 and retained the maximum amount of heavy metals in the soil by forming a CaCO3 shield on the heavy metals, thus decreasing their mobility. An approximate improvement of 30% in the retention of heavy metal ions was observed in soils treated with ESs when compared to untreated soil samples. Therefore, the study suggests that ESs can be an effective alternative in the remediation of soils contaminated with heavy metal ions.

AbstractThe Green Revolution is often seen as epitomising the dawn of scientific and technological advancement and modernity in the agricultural sector across developing countries, a process that unfolded from the 1940s through to the 1980s. Despite the time that has elapsed, this episode of the past continues to resonate today, and still shapes the institutions and practices of agricultural science and technology. In Brazil, China, and India, narratives of science-led agricultural transformations portray that period in glorifying terms—entailing pressing national imperatives, unprecedented achievements, and heroic individuals or organizations. These “epic narratives” draw on the past to produce meaning and empower the actors that deploy them. Epic narratives are reproduced over time and perpetuate a conviction about the heroic power of science and technology in agricultural development. By crafting history and cultivating a sense of scientific nationalism, exceptionalism, and heritage, these epic narratives sustain power-knowledge relations in agricultural science and technology, which are underpinned by a hegemonic modernization paradigm. Unravelling the processes of assemblage and reproduction of epic narratives helps us make sense of how science and technology actors draw on their subjective representations of the past to assert their position in the field at present. This includes making claims about their credentials to envision and deliver sustainable solutions for agriculture into the future.

Abstract The study is aimed to evaluate the combustion and emission characteristics of a partially premixed charge compression ignition (PCCI) engine with diesel and ethanol fuels. Ethanol was fumigated with preheated intake air at 40°C and inducted into the intake manifold of the test engine. Experimental tests were carried out with varying proportions of premixed ethanol at different engine loading conditions of 1, 2, 3, and 4 bar brake mean effective pressures (BMEP). It was explored that at lower BMEP, oxides of nitrogen (NOx) were decreased with an increment of premixed ethanol, however, at higher BMEP, the emissions increased. At all loads, smoke opacity decreased exceedingly with increasing premixed ethanol share. At part loads, hydrocarbon (HC) and carbon monoxide (CO) emissions were increased because of the high latent heat of vaporization of ethanol. Net heat release rate and in-cylinder pressure rise were found to be increased with an increasing engine load. Overall, it could be determined that the performance of the PCCI engine with ethanol fumigation is comparable with the conventional diesel fuel operation.