residual fraction
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Abstract Gasoline compression ignition (GCI) is a cost-effective approach to achieving diesel-like efficiencies with low emissions. The fundamental architecture of the two-stroke Achates Power Opposed-Piston Engine (OP Engine) enables GCI by decoupling piston motion from cylinder scavenging, allowing for flexible and independent control of cylinder residual fraction and temperature leading to improved low load combustion. In addition, the high peak cylinder pressure and noise challenges at high-load operation are mitigated by the lower BMEP operation and faster heat release for the same pressure rise rate of the OP Engine. These advantages further solidify the performance benefits of the OP Engine and emonstrate the near-term feasibility of advanced combustion technologies, enabled by the opposed-piston architecture. This paper presents initial results from a steady state testing on a brand new 2.7L OP GCI multi-cylinder engine designed for light-duty truck applications. Successful GCI operation calls for high compression ratio, leading to higher combustion stability at low-loads, higher efficiencies, and lower cycle HC+NOX emissions. Initial results show a cycle average brake thermal efficiency of 31.7%, which is already greater than 11% conventional engines, after only ten weeks of testing. Emissions results suggest that Tier 3 Bin 160 levels can be achieved using a traditional diesel after-treatment system. Combustion noise was well controlled at or below the USCAR limits. In addition, initial results on catalyst light-off mode with GCI are also presented.

Abstract The geochemical fractionation of toxic heavy metals Cd, Pb, Cr, Co, Mn, Ni, Cu, Fe and Zn was investigated in 10 different sites of river bed sediments (up, mid and downstream) of Gomti River at Lucknow city. Sequential extraction technique was used to identify the distribution of trace elements binding in different fractions i.e., exchangeable, carbonate, Fe and Mn oxide, organic matter and residual. Heavy metal concentrations were least at upstream and significantly higher in mid and downstream. Fractionation indicated that dominant metals were bound in residual fraction to the bed sediments except for Cd and Pb which were bound in an equivalent fraction. Geo-accumulation index factor reveals that the enrichment of heavy metals in the bio-available fraction is contributed anthropogenically. Hierarchical cluster analysis also shows the metal pollution load in the river. Risk assessment code of Cd and Ni showed very high risk (ranged from 54.41 to 85.56 and 20.57 to 44.92 respectively) followed by Pb (high risk), Zn, Co (medium risk), Cr, Mn, Cu, Fe (low risk) in Gomti River water. Further, concentrations of Cd and Pb at mid Lucknow were 31 and 75%, high enough to pose a substantial risk to the environment.

The density of anthropogenic activity in the port of blue fish leads to the contribution of heavy metals in sediments. The method of leaching is an important method to dissolve all zinc in the sediment precision and accuracy. Research on zinc levels in sediments has been widely practiced, but fractionation and distribution of zinc attachment in Blue Spring sediment using BCR Sonification. The results of the zinc analysis using BCR Sonification method gave precision value of 0.49 percent, and accuracy of 91.20 percent, the results showed that BCR method has high precision and accuracy value. The fractionation of zinc metal in the sediments shows that zinc is dominant in non-resistant (1) fractions comprising an ion exchange fraction, (2) carbonate bound fraction, (3) reduction fraction and (3) an oxidation fraction with a percentage of 10.16 percent; 23.52 percent; 21.25 percent. Whereas in the fraction resistant or residual fraction the concentration of zinc in the sediment was 45.07%. The distribution of zinc levels in sediments at nine locations in Sendang Biru ranged from 36.6 mg/kg - 239,78mg/ kg indicating that the Blue Sendang sediment was partly contaminated from anthropogenic because the zinc levels had exceeded the ereference of 120 mg/ kg. Padatnya kegiatan antropogenik di pelabuhan ikan sendang biru menyebabkan adanya kontribusi seng dalam sedimen. Metode leaching merupakan metode yang penting untuk melarutkan semua seng dalam sedimen secara presisi dan akurasi. Penelitian kadar seng dalam sedimen telah banyak dilakukan, tetapi fraksinasi dan distribusi keterikatan seng dalam sedimen Sendang Biru menggunakan metode BCR Sonifikasi. Hasil penelitian analisis seng menggunakan metode BCR Sonifikasi memberikan nilai presisi sebesar 0,49 persen, dan akurasi sebesar 91,20 persen, hasil tersebut menunjukkan bahwa metode BCR memiliki nilai presisi dan akurasi yang tinggi. Fraksinasi logam seng dalam sedimen menunjukkan bahwa seng dominan pada fraksi non resisten yang terdiri dari fraksi (1) pertukaran ion, (2) fraksi terikat karbonat, (3) fraksi reduksi, dan (4) fraksi oksidasi dengan presentase sebesar 10,16 persen; 23,52 persen; 21,25 persen, sedangkan pada fraksi resisten atau fraksi residu konsentrasi seng dalam sedimen adalah 45,07 persen. Distribusi kadar seng dalam sedimen pada sembilan lokasi di Sendang Biru berkisar antara 36,6mg/kg - 239,78mg/kg. Hal ini menunjukkan bahwa sedimen Sendang Biru sebagian terkontaminasi dari antropogenik dengan kadar melebihi ambang batas yaitu sebesar 120 mg/kg.

A synthetic microbial consortium called Effective Microorganisms (EM) consists mainly of photosynthetic bacteria, lactic acid bacteria and yeast. Various effects of EM∙XGOLD, a health drink produced by EM, on life cycle of Dictyostelium discoideum were described previously. Here, we report our attempt to identify the active principle, termed EMF, that brought about the observed effects. Throughout the purification processes, the presence of the active principle was monitored by promoted fruiting body formation. By liquid-liquid separation the activity was recovered in aqueous phase, which, after concentration, was further subjected to reverse-phase column chromatography. No activity was detected in any eluant, while almost all the activity was recovered in residual insoluble material. The application of conventional organic chemistry procedures to the residual fraction did not lead to any informative results. Acid treatment of the insoluble material produced air bubbles, suggesting it to be composed of some inorganic carbonate. Viewed under scanning electronmicroscope, the residue revealed spherical particles of μm size range. Energy Dispersive X-ray (EDX) Spectroscopy pointed to the existence, on the surface of the particles, of magnesium and, to a certain extent, of potassium. In separate experiments, acid treatment and alkali neutralization of EM∙XGOLD completely wiped out the stimulatory activity of fruiting body formation. These lines of evidence indicate these Mg, K-containing microparticles to be an active principle of EM culture extract. How these particles exert their effect is currently under intensive investigation.

The risk associated with the presence of heavy metals in soil is their potential toxicity and ability to enter the ecosystem through the food chain. Total heavy metal content of a soil is inadequate for predicting the toxicity of heavy metals in soil. Therefore, the current study was designed to determine the various forms in which the selected heavy metals: Chromium (Cr), Lead (Pb), Nickel (Ni), and Cadmium (Cd) exist in the soil to ascertain the available forms for plant uptake. Soils samples were randomly collected from selected organic and conventional farms in Akinyele local government, Ibadan, Oyo State, Nigeria, at different depths (0-15, 15-30 and 30-45 cm) using random sampling method. Routine analysis was carried out to determine the textural classes and chemical properties of soil samples. The total heavy metals of the soil samples were determined and their fractions were analysed using sequential extraction method. Cadmium was not detected in most of the soil samples. Residual fraction was predominant in all the analysed heavy metals. In addition, Cr was more associated with the oxidizable fraction having a range of 0.1 mg/kg from Ajibode organic farm (AO) at 30-45 cm depth. Pb and Ni were both more associated with reducible fraction with Pb having a range of 2.7 mg/kg in Ajibode conventional farm (AI) at 0-15 cm depth and 0.1 mg/kg in (AI) at 30-45 cm depth. Reducible values of Ni ranges from 4.3 mg/kg in AI at 0-15 cm to 1.4 mg/kg in AO at 30-45 cm. The apparent mobility and bioavailability for these heavy metals in the studied soils were in the order: Pb>Cr>Ni. The result showed that uptake of heavy metals by the plants would be low as the concentration of the exchangeable form of the heavy metals in the analysed soil sample has the least concentration when compared with the other forms.

Abstract The hyporheic zone (HZ) is an active biogeochemical region where groundwater and surface water mix and a potential reservoir for antibiotic resistance genes (ARGs). In this paper, the relative abundance and spatial distribution of ARGs in the HZ media was investigated, taking into consideration both the 5 speciation of 6 metals and the local characteristics. The samples of surface water, groundwater and sediment were collected from Zaohe-Weihe rivers of Xi’an City, which is representative cities with characteristics of the north-west region region of China. Of 271 ARGs associated with 9 antibiotics, 228 were detected, with a total detection rate of 84%. Sulfonamide and aminoglycoside ARGs were the dominant types of ARGs. The top 6 ARGs and mobile genetic elements (MGEs) in terms of abundance were tnpA-04, cepA, sul1, aadA2-03, sul2 and intI1. The results of principal component analysis (PCA) showed that the distribution characteristics of ARGs were not associated with the sampling sites but with the environmental medias. Similarity in the water phases and significant differences in the water and sediment phases were found. The redundancy analysis (RDA) identified the key factors controlling ARG pollution, including dissolved oxygen (DO) in surface water, total nitrogen (TN) in groundwater and total organic carbon (TOC) in sediments. In terms of the speciation of heavy metals, we further revealed the promotion effect between ARGs and heavy metals, especially the residual fraction of Ni. In terms of horizontal transfer mechanism, ARGs were significantly correlated with tnpA-03 in water phase, and were significantly correlated with tnpA-04 in sediment. In the three media, intI1 and ARGs, all show a significant correlation. These findings showed that hyporheic zone exerted a bottleneck effect on the distribution and transfer of ARGs.

Aims: The aim of this study was to evaluate the anti-inflammatory and analgesic activities of Daniellia oliveri methanolic extract and its fractions in NMRI mice. Study Design: In vivo acute toxicity, anti-inflammatory and analgesic assays. Place and Duration of Study: The work was carried out in the Department of Traditional Pharmacopoeia and Pharmacy (MEPHATRA / PH) of the Research Institute for Health Sciences (IRSS) Ouagadougou (Burkina- Faso) between December 2020 and February 2021. Methodology: The toxicity of the extracts was assessed according to OECD guideline 423 of 2001 at a single dose of 2000 mg / kg body weight. Analgesic effect was evaluated on the number of abdominal contortions induced by the intraperitoneal injection of acetic acid and the anti-inflammatory activity using the Carrageenan anti-edematous test was determined according to Winter. Results: The results of the acute oral toxicity study in mice showed no clinical signs of toxicity at dose of 2000 mg/kg b.w. The lethal dose (LD50) value estimated to 5000 mg/kg. The extracts reduced edema from the first hour, then by the third hour and maximum inhibition was achieved by the fifth hour after the injection of carrageenan. Extract and methanolic fraction at different doses showed significant inhibition of abdominal contortions in mice in a dose dependent manner. At 200mg the analgesic effect of methanolic fraction and crude extract was 53.70±1.29% and 41.38±1.25% respectively. At 400 mg/kg, the methanolic fraction inhibited carragenaan-induced edema by 85.97±5.67%. Conclusion: Daniellia oliveri is an important source of anti-inflammatory and analgesic compounds, justifying the use of this plant in traditional medicine for the treatment of inflammatory diseases.

In internal combustion engines, the chemical composition of the trapped fuel-air-residual gas mixture controls the nature of combustion, which, in turn, determines the characteristics of the ensuing emissions and work production processes. Therefore, knowledge of the trapped mixture’s composition is critical for reliably predicting and controlling engine performance, emissions, and efficiency. A good index of the overall trapped mixture composition is the trapped equivalence ratio. Unfortunately, in two-stroke engines, it is unfeasible to accurately determine the trapped equivalence ratio using traditional intake flow measurements and exhaust emissions data. This limitation arises from the simultaneous occurrence of intake and exhaust processes in two-stroke engines, which causes: (1) exhaust emissions to be diluted by excess fresh air that was supplied for achieving effective gas exchange, that is trapping inefficiencies and (2) a significant fraction of combustion products to stay back in the cylinder as residual gas, that is scavenging inefficiencies. The current paper presents an experimental study carried out on a cross-scavenged, lean-burn, natural-gas, two-stroke engine to characterize its scavenging performance, thus paving the way for trapped equivalence ratio computation. CO2 is used as a tracer for combustion products, and its concentration is tracked in the combustion chamber and exhaust manifold on a crank-angle-resolved basis using high-speed nondispersive infrared sensors. The changes in cylinder CO2 concentration before and after gas exchange are used to determine the trapped residual fraction and various features of the exhaust CO2“wave” are used to explain the temporal progression of the gas exchange process. The presented results show the effects of changes in engine operation (speed, load, and spark-timing) on the engine’s scavenging efficiency. Speed and load changes are found to have the most pronounced effects, which result from changes in port open duration and phasing of reflected waves in the exhaust.

Abstract This study investigated the spatial, vertical and fraction distribution, multivariate statistical analysis, as well as assessed pollution levels and health risks posed by heavy metals at the Wenshan mining area. There were 6 sampling points at the site, from which a total of 32 samples were collected. The eastern and south-eastern parts of the site were heavily polluted, while the western and north-western parts were less contaminated. As pollution was particularly severe in the topsoil, with the mean value of 503.31 mg kg− 1 being more than 25-fold higher than the risk screening value. As content in all layers was greater than the standard risk screening value in the three typical profiles. The proportion of various Ni, Cu and As fractions changed slightly with depth at all three sampling points, and the residual fraction percentage accounted for more or nearly 80% of the total concentration. In addition, a significantly negative correlation (p < 0.05) was detected between Ni and As (-0.85), indicating a different source of these two elements. Principal component analysis demonstrated that two PCs, i.e. PC1, attributed to human activities, e.g. mining activities and transport, and PC2, defined as natural sources, were responsible for 80.632% of the total variance. As posed severe ecological and unacceptable health risks, i.e. non-carcinogenic and carcinogenic risks both for adults and children. Therefore, a comprehensive understanding of the characteristics of mining pollutants and improved emission management in the mining process are essential to protect the environment and health of local residents.

Waste cement is a construction and demolition waste produced from old buildings’ demolition and transformation. In recent years, the recycling of recycled concrete is limited to the use of recycled aggregate, and the research on the utilization of waste cement in waste concrete is scarce. This study explored the effective application of waste cement for the adsorption of cadmium (Cd2+) from an aqueous solution and the bioavailability and immobility of Cd2+ in soil. Results showed that the maximum adsorption capacities of ordinary Portland cement(OPC) paste, fly ash cement (FAC) paste, and zeolite cement (ZEC) paste for Cd2+ were calculated to be 10.97, 9.47, 4.63 mg·g−1, respectively. The possible mechanisms for Cd2+ adsorption in the solution by waste cement mainly involve precipitation by forming insoluble Cd2+ compounds in alkaline conditions, and ion exchange for Cd2+ with the exchangeable calcium ions in waste cement, which were confirmed by XRD and SEM. Results from diethylene triaminepentaacetic acid (DTPA) extraction and toxicity characteristic leaching procedure (TCLP) implied reduction of the Cd2+ mobility. DTPA-extractable Cd2+ decreased by 52, 48 and 46%, respectively, by adding 1% OPC, FAC and ZEC. TCLP-extractable Cd2+ decreased by 89.0, 80.3, and 56.0% after 1% OPC, FAC, and ZEC treatment, respectively. BCR analyses indicate that OPC, FAC, and ZEC applications increased the percentage of Cd2+ in residual fraction and induced a high reduction in the acid-soluble Cd2+ proportion. The leaching column test further confirmed a reduction in Cd2+ mobility by waste cement treated under continuous leaching of simulated acid rain (SAR). Therefore, waste cement exhibited a significant enhancement in the immobilization of Cd2+ under simulated acid rain (SAR) leaching. In summary, the application of alkaline waste cement could substantially remove Cd2+ from wastewater and reduce Cd2+ mobility and bioavailability in contaminated soil.