Environmental Parameters Research Articles

The Troll Observing Network (TONe): plugging observation holes in Dronning Maud Land, Antarctica

Antarctica and the Southern Ocean play vital roles in the Earth system, exerting significant influence on global atmospheric, cryospheric, and oceanic processes. Understanding the ongoing changes in Antarctica and their broader impact on global dynamics is imperative. Achieving this understanding necessitates dedicated and coordinated observations of environmental parameters in the region. The Troll Observing Network (TONe) is Norway's proactive initiative to the call for sustained, coordinated, complementary, geographically spread, and societally relevant long-term observations from Antarctica. Centered around the Troll Research Station in Dronning Maud Land, a region characterized by limited data availability, TONe constitutes a comprehensive state-of-the-art observatory network, specifically designed for environmental observations for studying and monitoring of the atmosphere, terrestrial, and marine environments. TONe aims to facilitate broad and open access to observational data and shared services to the international research communities as a foundation for acquiring knowledge of societal significance. TONe will, however, be a limited contribution the broader international data gathering effort required to underpin a strengthened understanding of Antarctica in the Earth system. TONE is an important initiative focused on a data sparse region of Antarctica, but has only substantial added value when seen in the context of similar ongoing and future efforts around the continent.

An efficient dual layer data aggregation scheme in clustered wireless sensor networks

AbstractIn wireless sensor network (WSN) monitoring systems, redundant data from sluggish environmental changes and overlapping sensing ranges can increase the volume of data sent by nodes, degrade the efficiency of information collection, and lead to the death of sensor nodes. To reduce the energy consumption of sensor nodes and prolong the life of WSNs, this study proposes a dual layer intracluster data fusion scheme based on ring buffer. To reduce redundant data and temporary anomalous data while guaranteeing the temporal coherence of data, the source nodes employ a binarized similarity function and sliding quartile detection based on the ring buffer. Based on the improved support degree function of weighted Pearson distance, the cluster head node performs a weighted fusion on the data received from the source nodes. Experimental results reveal that the scheme proposed in this study has clear advantages in three aspects: the number of remaining nodes, residual energy, and the number of packets transmitted. The data fusion of the proposed scheme is confined to the data fusion of the same attribute environment parameters.

Lunar regolith water ice simulation method and characterization

The exploration of lunar water resources has always been a cutting-edge topic in human space exploration. This paper presents a method for gas deposition and ice formation to simulate the mixture of ice and regolith in lunar polar shadowed regions. Following the principles of “physical structure equivalence and environmental parameter approximation,” based on the principle of water molecule deposition and adsorption in a cold trap environment, water ice is converted into water vapor by raising the temperature in a vacuum environment. Then, water molecules deposit and adsorb on the surface of dry, low-temperature mineral particles, forming an ice film under the action of the cold trap capture principle. The morphology and occurrence status of the particle surface ice film has been obtained through microscopic characterization of the samples in a cold environment. Vacuum pressure monitoring equipment is used to verify the pressure changes of water during the sublimation and deposition, and the phase diagram of water is analyzed to understand its state changes within the simulated setup. Samples are retrieved from a high-purity nitrogen glove box, and their water content is verified using thermogravimetric analysis (TGA). The effectiveness of the proposed lunar regolith simulation method is validated through macroscopic and microscopic approaches. This method provides high-fidelity samples for lunar water resource utilization, scientific exploration, and payload development on the Moon.

IoT ENBALED SMART AQUARIUM FOR MONITORING THROUGH SENSORS

The development of an IoT-enabled smart aquarium system offering real-time monitoring and automated control of crucial environmental parameters. The core of the system lies in the ESP8266 microcontroller, facilitating seamless internet connectivity and data processing. Water quality assessment is achieved through a turbidity sensor, detecting suspended particles indicative of potential pollution. Environmental conditions are monitored using a DHT11 sensor, providing data on both temperature and humidity – essential factors for maintaining a healthy habitat for specific fish species. For automated lighting control mimicking natural day/night cycles and preventing excessive algae growth, a Light-Dependent Resistor (LDR) is implemented. The LDR adjusts aquarium lighting based on ambient light levels. Finally, a relay module controls the operation of a water pump, ensuring optimal water circulation and distribution of nutrients throughout the aquarium. While an I2C LCD connected to an Arduino Nano provides local data visualization within the aquarium setup, the ESP8266 transmits sensor readings to a user-friendly platform accessible remotely through a mobile application or web interface. This allows for convenient real-time monitoring of water quality, temperature, humidity, and lighting conditions. The system can be further programmed to generate alerts when critical parameters deviate from the ideal range, enabling proactive user intervention to maintain a healthy environment. This project demonstrates the potential of IoT technology to create a more automated, efficient, and user-friendly system for maintaining a thriving aquatic ecosystem. KEYWORDS: IoT (Internet of Things), Smart Aquarium, ESP8266, Turbidity Sensor, DHT11 Sensor, LDR(Light-Dependent Resistor), Relay Module, Water Pump, I2C LCD, Arduino Nano, Real-Time Monitoring, Automated Control, Remote Access, Mobile Application, Web Interface, Water Quality, Temperature, Humidity, Light Control, Aquatic Environment.

Anthropogenic eutrophication and stratification strength control hypoxia in the Yangtze Estuary

Many large estuaries are threatened by intensifying hypoxia. However, due to the limited duration of available observations, uncertainties persist regarding the level of contemporary hypoxia intensity in a longer-term context and the relative contributions of climate versus human factors. Here we present sediment records for the hypoxia intensity and associated environmental parameters in the Yangtze Estuary over the past three centuries. The results show that the hypoxia intensity has been increasing during the last half century due to anthropogenic eutrophication, but the current hypoxia condition is not as severe as some preindustrial periods due to weaker stratification in the water column. Our findings suggest that if anthropogenic and climatic forcing coincide in the foreseeable future, the hypoxia intensity of the Yangtze Estuary may reach unprecedented levels.

Differences in archaeal diversity and potential ecological functions between saline and hypersaline lakes on Qinghai-Tibet Plateau were driven by multiple environmental and non-environmental factors beyond the salinity

BackgroundSaline lakes are home to various archaea that play special and crucial roles in the global biogeochemical cycle. The Qinghai-Tibet Plateau hosts a large number of lakes with diverse salinity ranging from 0.1 to over 400 g/L, harboring complex and diverse archaea. To the best of our knowledge, the formation mechanisms and potential ecological roles of archaea in Qinghai-Tibetan Plateau saline lakes remain largely unknown.ResultsUsing High-throughput Illumina sequencing, we uncovered the vastly distinct archaea communities between two typical saline lakes with significant salinity differences on the Qinghai Tibet Plateau (Qinghai saline lake and Chaka hypersaline lake) and suggested archaea played different important roles in methanogenesis-related and nitrate reduction-related functions of these two lakes, respectively. Rather than the individual effect of salinity, the composite effect of salinity with diverse environmental parameters (e.g., temperature, chlorophyll a, total nitrogen, and total phosphorus) dominated the explanation of the variations in archaeal community structure in different habitats. Based on the network analysis, we further found the correlations between dominant archaeal OTUs were tight but significantly different between the two habitats, implying that archaeal interactions may also largely determine the shape of archaeal communities.ConclusionThe present study improved our understanding of the structure and function of archaea in different saline lakes on the Qinghai-Tibet Plateau and provided a new perspective on the mechanisms underlying shaping their communities.

Year-round monitoring of three water sources in Québec, Canada, reveals site-specific differences in conditions for Cryptosporidium and Giardia contamination.

Cryptosporidium and Giardia are protozoan parasites responsible for gastrointestinal illnesses in humans and in animal species. The main way these parasites are transmitted is by ingestion of their (oo)cysts in drinking water. Monitoring (oo)cysts in water sources is beneficial to evaluate the quality of raw water supplying treatment plants. Currently, the only standardized protocol to enumerate these parasites from water samples is United States Environmental Protection Agency (USEPA) Method 1623.1. With this method, we monitored three major water sources in Quebec over a year to assess temporal and geographical variations of these parasite (oo)cysts. These three water sources have independent watersheds despite being in the same region. We found a general pattern for Giardia, with high concentrations of cysts during cold and transition periods, and significantly lower concentrations during the warm period. Cryptosporidium's concentration was more variable throughout the year. Statistical correlations (Pearson's correlation coefficients) were established between the concentration of each parasite and various environmental parameters. The three study sites each showed unique factors correlating with the presence of both protozoa, supporting the idea that each water source must be seen as a unique entity with its own particular characteristics and therefore, must be monitored independently. Although some environmental parameters could be interesting proxies to the parasitic load, no parameter was strongly correlated throughout the whole sampling year and none of the parameters could be used as a single proxy for all three studies sources.

Concentration, composition and exposure risk assessment of particulate matter with different particle sizes in subway stations

Particle composition and risk assessment of their exposure in a subway station are very important for a station's environment and the health of people. However, only a handful of papers have compared and analyzed the composition of particulate matter and the risk of their exposure to people. To address these issues, environmental parameters and particulate matter were measured for one month at six different locations in twelve subway stations in a capital city located on the central coast of China. The particulate matter (PM), its composition and characteristics were analyzed and compared. The daily average exposure risk assessment model for the studied city was proposed to analyze the exposure risks associated with various particulate matters and metals for both commuters and workers. The results showed that, in all public areas (station hall, platform and carriage), the concentrations of PM were higher than those outside the subway station. The highest values of PM2.5, PM10, and TSP (total suspended particulates) were determined to be 158.3 μg/m3, 168.0 μg/m3, and 170.7 μg/m3, respectively. The physical characteristics showed that the surface of particles inside the station was rougher, larger and darker in color. Compared to outdoors, the particles within the subway stations contained much more metals, particularly Fe that had the mass fraction of 9.59 %. On the other hand, the outdoor environment did not contain any Fe. These findings indicated that there were original sources of contamination at subway stations, and the hazardous nature of the particles was particularly pronounced within subway stations. The exposure risk of TSP and metals for workers was nearly twice that of passengers. This study aims to provide data that could help in controlling the environment at subway stations.

Detection of Perkinsus sp. in Chionista fluctifraga cultivated in the southeast Gulf of California

Objective. To determine the presence of Perkinsus sp. in the sand clam Chionista fluctifraga cultivated in an intertidal zone of the southeastern Gulf of California, using Ray's thioglycollate fluid medium staining (MFTR) and polymerase chain reaction (PCR). Material and Methods. The prevalence and parasite load of Perkinsus sp. were monthly obtained and correlated with environmental water conditions and clam biometric indicators (n = 540), from May 2018 to September 2019. Results. Presumptive hypnospores of the protozoan were detected in eight months of culture. The prevalence fluctuated from 3.3% to 13.3%, while the average parasite load ranged from 2 to 1286 hypnospores/g of tissue. The intensity of infection varied from negative to light. The prevalence and parasite load were correlated with each other (r=0.61, P˂0.05) but not with the environmental parameters, nor with the biometric indicators of the clam. The PCR test was negative for the MFTR positive cases. Conclusions. Presumptive hypnospores of Perkinsus sp. were detected in C. fluctifraga without clear indications of infection that compromised the clam health in culture. The constant monitoring of Perkinsus sp. in C. fluctifraga is highly recommended to establish possible infections.

Transmission mechanism of antibiotic resistance genes and their differences between water and sediment in the Weihe River Basin

Antibiotic resistance genes (ARGs) are emerging microbial pollutants that are regulated by many factors and pose potential threats to aquatic environments. In this study, we used network analysis, correlation analysis, and constructed models based on metagenomic sequencing results to explore the spatial patterns, impact mechanisms, transmission risks and differences in ARGs in the water and sediment of the Weihe River Basin. The findings revealed notable disparities in ARGs, mobile genetic elements (MGEs), and bacterial communities. In the sediment, the abundance of ARGs was considerably greater than that in water. Moreover, the percentage of ARGs shared by the two components reached a value of 85.8%. Through network analysis, it was determined that the presence of 16 MGEs and 20 bacterial phyla was strongly associated with ARGs (R2 > 0.7, P < 0.05). The Mantel test showed that abiotic factors including DO, pH, nutrients, and heavy metals played important roles in the distribution of ARGs (P < 0.05). A structural equation model revealed that the key factors influencing the distribution of ARGs in water were bacterial diversity and environmental parameters (standardized effects of −0.730 and −0.667), and those in sediment were bacterial diversity and MGEs (standardized effects of −0.751 and 0.851). Neutral modeling indicated that deterministic processes played an important role in the assembly of ARGs in the water of the Weihe River Basin, and stochastic processes were dominant in the sediment. There was a highly significant positive linear correlation between ARGs and pathogens, and there was more complex co-occurrence in the water than in the sediment (R2 > 0.9, P < 0.05), with stronger migration and transmission occurring. Exploring ARGs in large-scale watersheds is immensely important for elucidating their traits and transmission mechanisms and consequently paving the way for the formulation of efficient strategies to mitigate resistance threats.

Adaptive features of winter triticale accessions from the VIR collection

Background. In the context of global climate change, the study and development of genetic material with environmental plasticity and stability in the manifestation of its traits becomes relevant. The scientific and practical results achieved in triticale breeding place this crop among the most popular cereals in terms of economic importance. However, the main problem for the use of triticale in breeding practice is its limited genetic resources.Materials and methods. The research materials were 161 winter triticale (× Triticosecale Wittm. ex A. Camus) accessions from the global collection of VIR. The study and breeding-oriented assessment of the material were based on conventional breeding techniques and carried out according to the guidelines approved by VIR with minor amendments. The obtained research data underwent statistical analysis using the method by A. V. Kilchevsky and L. V. Khotyleva.Results. Environmental and genetic parameters were analyzed under the conditions of the Middle Volga Region of Russia. Genotypes were identified for their high general adaptability, i. e., securing the highest average yield in the entire set of environments. Cultivars were also selected for their least variable high yields under the impact of weather conditions. The analysis of the studied set of accessions showed that both high-yielding and low-yielding genotypes were stable. The character’s mean value and its environmental sensitivity were relatively independent and could be incorporated in one genotype in various combinations. This finding can be used in the process of triticale breeding.

A dynamic ventilation strategy for industrial buildings based on weight factors

In industrial buildings, pollution sources are often multi-point and unstable. This study proposes a dynamic exhaust strategy (DES) that aims to balance energy utilization efficiency and system performance without the need for monitoring indoor environmental parameters. Firstly, the DES system only monitors the local pollutant concentration in each outlet to determine its “exhaust potential”. Weight factors are then assigned to adjust the total exhaust flowrate, achieving real-time dynamic weight allocation (DWA) and improving the system performance in removing pollutants. Secondly, the system monitors the total pollutants removal from all outlets to enable dynamic total exhaust flowrate adjustment (DTA) to reduce energy consumption. A stochastic release model of multiple pollution sources was established in a typical thermally polluted workshop, and numerical simulations were conducted to investigate the effects of factors such as the stochastic non-uniformity of sources release, frequency and range of dynamic parameter adjustments, and energy-saving potential of the DES system. The results indicate that the DES system demonstrates increased effectiveness in pollutants removal as the randomness of the sources release increases, with a 12 % improvement in capture efficiency η compared to the unregulated system. Additionally, by utilizing 80 % of the total exhaust flowrate to adjust it at a frequency of 5 s per time in the DWA process, the system can meet requirements for pollutants removal, performance, and stability. Furthermore, the co-regulation of the DWA and DTA processes can reduce energy consumption by 78 % while maintaining an 81 % capture efficiency compared to using the DWA alone.

Spatial distribution models for the four commercial tuna in the sea of maritime continent using multi-sensor remote sensing and maximum entropy

The dynamic of marine environmental parameters affects the distribution of commercial tuna in the sea of the maritime continent. Hence, the objectives of this study are to develop spatial distribution models for the four main tuna species in the Maritime continent's sea with reasonable accuracy, identify their correlation with marine environmental parameters, and investigate areas of interaction between those tuna species. The study develops the distribution models for albacore (Thunnus alalunga), bigeye (Thunnus obesus), yellowfin (Thunnus albacares), and skipjack (Katsuwonus pelamis) tuna species, utilizing multi-sensor satellite remote sensing and maximum entropy. The results show models have good performance, focusing on environmental factors such as sea surface temperature (SST), chlorophyll-a (CHL), and sea surface height anomalies (SSHA), combined with eddy kinetic energy (EKE). Seasonal variations in potential tuna habitats are revealed, emphasizing the influence of those marine environmental conditions. From December to May, the four commercial tuna species were distributed in conditions characterized by SST of 26–31.5 °C, CHL levels of 0–3 mg/l, SSHA of −0.3 to 0.2 m, and EKE of 0–1 m2/s2, while from June to November, they experienced SST of 23–31 °C, CHL levels of 0–4 mg/l, SSHA of −0.5 to 0.3 m, and EKE of 0–1.1 m2/s2. The spatial persistence of the four tuna species emerged mainly around the south sea of Java, with skipjack being the most common species found in the sea of the maritime continent. With sufficient and evenly distributed tuna presence records, the results indicate the potential for extrapolation beyond the training data to estimate habitat suitability for the four commercial tuna distributions. The results also suggest potential competition between tuna species sharing ecological niches and highlight possible overlapping areas where different tuna species interact with the same fishing gear.

Stability of Immobilized Chemosensor‐Filled Vesicles on Anti‐Fouling Polymer Brush Surfaces

AbstractThe characterization of phospholipid membrane permeability for small molecules is crucial for many applications in drug discovery and biomedical research in general. Here, chemosensor‐laden vesicles offer an attractive platform for permeability assays. In this work, the stability of immobilized chemosensor‐filled vesicles is explored on anti‐fouling polymer brush surfaces for potential use in monitoring small molecule membrane permeability. The study focuses on the development of a method for immobilizing sensor‐loaded vesicles into arbitrary patterns on surfaces and characterizing their stability under changing temperatures and compositions. As substrate to enable intact, long‐term stable vesicle immobilization reactive polymer brushes with anti‐fouling properties are used. Utilizing microchannel cantilever spotting, biotin moieties are introduced on the polymer brush surface, enabling stable tethering of vesicles through streptavidin‐biotin interactions. The immobilized vesicles are monitored through fluorescence microscopy for their response to analytes under changing environmental parameters and vesicle composition. A higher stability of immobilized vesicles compared to free‐floating ones is observed, with permeability only at elevated temperatures. By tuning vesicle compositions, permeability at lower temperatures can be raised again. Overall, the study provides insights into a novel approach for vesicle immobilization, showcasing the potential of surface‐bound vesicles for applications in microfluidic systems and as biosensors in various assays.

Exploring the relationship of the winter-spring crop’s rice yield with meteorological drought and water resources in Ben Tre province

Recent environmental changes have significantly impacted rice cultivation in Ben Tre province, the Vietnamese Mekong Delta (VMD) coastal province. This research employed the Mann-Kendall (MK) non-parametric method and Sen’s slope (SS) technique to detect trends in the rice yield of the winter-spring crop (WSC) in Ben Tre province and environmental parameters from 2009 to 2020. These environmental parameters include the meteorological drought index and key water resource metrics, potentially affecting the region’s rice yield. Furthermore, it established the relationship between these environmental parameters and rice yield using multiple linear regression. The results indicated an average decrease of 0.13 ton/ha/year in the WSC’s rice yield, with a severe reduction to 2.86 ton/ha in 2016. This decline in rice yield is likely attributed to environmental shifts, particularly during years with extreme hydrological events. The study found that during the months of dry season, from January to April, there was a decrease of 0.14 per year in the minimum Standardized Precipitation Evapotranspiration Index (SPEI-4min) at the Ben Tre meteorological station; an increase in the minimum daily discharge at the Tan Chau station (QTCmin) by 81 m3/s/year; a decrease in the mean daily water level at the My Thuan station (QMTmean) by 0.22 cm/year; and an increase in the maximum daily water level at the Ben Trai station (HBTmax) by 0.67 cm/year. However, the maximum daily salinity concentration at the Tra Vinh station (STVmax) showed no significant trend, oscillating between 6.5 and 15 g/l, potentially because the three-hourly monitoring intervals might not have fully captured peak salinity levels. The regression model identified SPEI-4min (with a Correlation Index (CI) of 0.450) and STVmax (CI = 0.372) as the primary factors influencing rice yield. Additionally, QTCmin and HBTmax were also significant, though to a lesser extent, with correlation indices of 0.310 and 0.303, respectively. Conversely, QMTmean had a relatively minor influence, with a correlation index of 0.136. These findings are crucial to developing adaptive strategies and policies for improving the resilience of rice production in the study province and throughout the VMD.

Microfluidic chips for microbially induced calcium carbonate precipitation: Advantages, challenges, and insights

Microbially induced calcium carbonate precipitation (MICP) has garnered significant attention as a biomineralization process with diverse applications spanning from construction to environmental remediation. To propel MICP research and deepen our comprehension of MICP mechanisms, microfluidic chips have emerged as potent tools offering precise control over environmental parameters and real-time observations. Herein, we explore the benefits and challenges associated with employing microfluidic chips as a platform for investigating MICP. The advantages of microfluidic chips lie in their capacity to create controlled microenvironments conducive to emulating specific conditions crucial for MICP. The high-throughput nature of these devices accelerates experimentation by facilitating simultaneous testing of various microbial strains and nutrient compositions. Throughout the MICP process, observations were made on the behaviors of both bacterial cells and CaCO3 cementation. The inherent reduction in reagent consumption offered by microfluidics is both cost-effective and environmentally friendly. However, scaling up from microscale findings to practical applications necessitates careful consideration. Fully replicating the three-dimensional complexity and heterogeneous structures of the soil matrix, which influence microbial behavior, mineral distribution, and overall precipitation dynamics, using microfluidic chips remains challenging. Additionally, certain environmental complexities, including macroscopic soil components such as organic matter and various particle types, which significantly affect microbial activities and mineral precipitation patterns, may be difficult to replicate in microfluidic setups. However, microfluidic chips stand as invaluable tools for advancing MICP research. By addressing the advantages and disadvantages outlined here, researchers can harness the capabilities of microfluidic systems to unravel the intricacies of MICP, ultimately bridging the gap between fundamental understanding and real-world applications.

Advanced Chemical and Imaging Methods for Studying Structure Morphology and Excipients Solid State Transformations in Pharmaceutical Multiparticulate Formulations

The formulation of paediatric medicines faces significant challenges to meet the requirements for safe and accurate administration, while maintaining a suitable taste. Multiparticulate formulations have a strong potential to address these challenges because they combine dose flexibility with ease of administration. Understanding the stability of multiparticulate formulations over storage as a function of time and environmental parameters, such as humidity and temperature, is important to manage their commercialisation and use. In this work, we have expanded the toolkit of available techniques for studying multiparticulates beyond those such as scanning electron microscopy (SEM) and confocal laser scanning microscopy. We include advanced methods of environmentally-controlled SEM to monitor temperature- and humidity-induced changes in-situ, and a variety of Raman spectroscopies including stimulated Raman scattering microscopy to identify and localise the different ingredients at the surface and inside the multiparticulates. These techniques allowed unprecedented monitoring of specific changes to the particulate structure and distribution of individual ingredients due to product aging. These methods should be considered as valuable novel tools for in-depth characterisation of multiparticulate formulations to further understand chemical changes occurring during their development, manufacturing and long-term storage. We envisage these techniques to be useful in furthering the development of future medicine formulations.

Nitrogen isotopes of marine oils in the Tarim Basin, China: Implications for the origin of organic matters and the paleoenvironment

Nitrogen isotope compositions (δ15N) of sedimentary rocks are usually used to reconstruct the paleoenvironment and nitrogen (N) biogeochemical cycle. The δ15N values of crude oils inherit the characteristics of relevant source rocks and can well reflect the information of hydrocarbon-forming organisms and environment in ancient water column. However, studies on the δ15N of crude oils are limited due to the low N content. In this study, a new efficient method is applied to the marine oils from the Bashituo (BST) and Halahatang (HLHT) areas of the Tarim Basin to obtain the nitrogenous components (i.e., nonhydrocarbons and asphaltenes) for the achievement of N concentration. The carbon and nitrogen isotopes of these components and the biomarkers of oils were measured. The δ15N values in asphaltenes (δ15NAsp) are significantly heavier than those in nonhydrocarbons (δ15NNSOs) in these oils, which are attributed to the potential directional N transfer and kinetic isotope fractionation during the thermal evolution of organic matters (OM). The δ15NAsp values have significant correlations with OM origin associated parameters and weak correlations with environmental parameters, suggesting that the difference in δ15NAsp values is mainly resulted from biological source rather than redox conditions. The δ15NNSOs values have a closer relationship with the redox condition than biological characteristics, indicating that they have a good response to paleoenvironmental variation in the water column, which is not completely overprinted by the difference of OM origin. Different redox conditions give rise to distinct nitrogen cycles, resulting in various δ15N values. Anammox occurs in the water column of the Early Cambrian dominated by physically stratified conditions with significant isotope fractionation, resulting in relatively heavier δ15N of OM in the BST area. In the Middle–Late Ordovician period, the limited suboxic zone leads to an insignificant positive bias of δ15N caused by partial denitrification in the HLHT oils. The evaluation of δ15N in nitrogenous fractions enables a more comprehensive reconstruction of N cycle for ancient oceans.

Evaluation of environmental parameters for optimal cell density, biomass, lipid, and biodiesel production in scenedesmus: Focus on suspension and biofilm methods

The study focused on investigating the impact of various environmental parameters on the production of Scenedesmus, a unicellular alga known for its industrial and food value. The parameters studied included production method, temperature, lighting period, light intensity, and pH, with a particular emphasis on suspension and biofilm production methods. The results highlighted optimal conditions for different aspects of production, such as cell density, biomass production, lipid production, and biodiesel production. Specifically, the findings indicated that the highest cell density was achieved at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 16 h, and pH of 8. For biomass production, the optimal conditions were a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 9. The greatest lipid production was observed at a temperature of 20 °C, light intensity of 4000 lux, lighting period of 18 h, and pH of 8. Moreover, the highest biodiesel production was recorded at a temperature of 25 °C, light intensity of 3000 lux, lighting period of 18 h, and pH of 8. Notably, the study found that the biofilm production method outperformed the suspension method across various parameters, including cell density, biomass production, lipid production, and biodiesel production. These results contribute to the existing knowledge of optimal conditions for microalgae production and underscore the potential of Scenedesmus in industrial and food applications.

Experimental Evaluation of the Methane Number Measurement Procedure for Gaseous Fuel Rating

Methane Number (MN) is a fuel rating technique for gaseous fuels analogous to Octane Number. This study establishes and shares a repeatable and reproducible method for MN determination of a gaseous fuel using a modified Cooperative Fuel Research Engine (CFR). Adaptations required to convert a CFR engine for use in the MN test procedure are identified. The investigation includes allowable environmental parameters and operating variation limits. An essential aspect of the MN method involves identifying and quantifying Knock Intensity (KI) during engine operation. CFR engines, originally designed for gasoline testing, come equipped with their own knock measurement systems utilizing a capacitive detonation sensor. The original system is compared with a Fast Fourier Transform (FFT) approach that uses a piezoelectric pressure transducer. Quantification of methane number requires an accurate assessment of the reference fuel blend (CH4 + H2). A comparison is carried out between dynamic blending using mass flow meters and bracketing using certified gas bottles containing various CH4/H2 blends from a gas supplier.