A Physical and Geochemical Characterization of Southwestern Ontario\u27s Breathing Well Region

The geology and groundwater geochemistry are described for a 1400km2 breathing well zone within a Middle Devonian, karstic carbonate aquifer system in southwestern Ontario. Breathing wells are unusual because they draw in or emit large volumes of air, depending on fluctuations in atmospheric pressure which causes an exchange of gases between the atmosphere and the subsurface. To better understand this connection, geochemical, hydraulic, and barometric data were used to investigate interconnectivity within the breathing well zone. Spatial and temporal analyses reveal that a significant amount of unsaturated void space exists within the Lucas Formation, and that hypoxic and high CO2 gases are emitted during low atmospheric pressure periods. The groundwater chemistry displays elevated trace metals (e.g. Ag, Cu, Pb, Zn) and SO42- resulting from combined evaporite dissolution and sulphide oxidation. This study provides data useful in understanding the type of environment in which breathing wells are found, and the nature of the subsurface vadose zone gases and groundwater movement in these systems. Keywords Breathing wells, karst, geochemistry, stable isotopes, hydrogeology, sulfide oxidation, evaporite dissolution, barometric loggin

Formic Acid Production From Photochemical Oxidation in condensed and Non-condensed Mechanisms

Organic acids are secondary components generated from the oxidation of volatile organic compounds in the atmosphere, affecting particulate matter composition, aerosol, and rain acidity. Among them, formic acid is the most abundant gas-phase organic acid, which has been observed over 2.5 ppbV in concentrations in rural areas. However, current atmospheric models’ predictions of formic acid are typically biased low, potentially because of the underestimation of direct emissions and chemistry. In our work, we first applied the Framework for 0-D Atmospheric Modeling version4 (F0AMv4) to simulate gas-phase formic acid using four current mechanisms (Master Chemical Mechanism (MCM) v3.3.1, GEOS-Chem Mechanism in version v12-08, SAPRC-07B mechanism and Carbon Bond 6 (CB6) mechanism). The observation data were collected in Yorkville, Georgia, lasted from September to October in 2016 during an intensive campaign. Like earlier studies, the modeled diurnal trend of formic acid was lower than the observation, showing a dissimilar diurnal profile. Then we used the box model combined with the observation data to understand the production of formic acid from isoprene oxidation. Our box model simulations revealed a large difference in formic acid production pathways among four isoprene oxidation mechanisms under different NOx levels. We discovered that MCM v3.3.1 was likely to underestimate formic acid production from isoprene oxidation because it only considered a small contribution from isoprene epoxydiol (IEPOX) peroxy radicals reacting with HO2 pathway. However, CB6 mechanism revealed the suppression of formic acid formation under a high NOx condition as proposed by recent studies, which was not included in all other mechanisms. This mechanism also greatly underestimated the formic acid production from isoprene reacting with ozone and overlooked the pathway from glycolaldehyde to formic. To better improve the formic acid prediction in the model, additional gas-phase reactions of isoprene and monoterpenes suggested by recent studies were added to our chemical mechanisms. After the modification, we could see a small increase in predicted formic acid concentration. However, these added reactions had little impact on the diel profile of formic acid. According to Gao et al. (2021), the model-measurement discrepancy in formic acid at Yorkville persists, despite modifications to the chemical mechanisms. Our work elaborated the formic acid pathways among each mechanism under different NOx levels and revealed the role of isoprene and monoterpenes in formic acid production. This shows that the missing monoterpene and isoprene photooxidation reactions discussed in recent studies might not be the only major missing components for formic acid predictions. Models should also consider incorporating other processes like emission.M.S

CHARACTERIZING A GROUNDWATER SYSTEM DOWNGRADIENT OF A COAL MINE WASTE ROCK DUMP, ELK VALLEY, BRITISH COLUMBIA, CANADA

Seepage from steelmaking coal mine waste rock dumps in the Elk Valley, British Columbia, Canada can contain selenium (Se), cadmium (Cd), and sulfate (SO42-) from the oxidation of sulfide minerals, and nitrate (NO3-) from blasting. The impact of these constituents of interest (CIs) on receiving groundwater systems and the potential for their natural attenuation is investigated. A 10.7 km2 mine-impacted research catchment (West Line Creek) was instrumented with 13 monitoring wells and 8 drivepoint wells to characterize the hydraulics and geochemistry of the aquifer system downgradient of the waste rock dump. These data were augmented with geophysical surveys and by characterizing the lithology, geotechnical properties, and geochemistry of core samples obtained during drilling. Furthermore, the groundwater monitoring program also facilitated the development of a conceptual model of hydrogeology in a small montane valley. An unconfined aquifer at the overburden/fractured bedrock interface, i.e. the basal alluvial aquifer was identified as the primary groundwater conduit for the migration of water and solutes from the waste rock dump toward Line Creek. Vertical and horizontal dispersion of CIs was confirmed with porewater analysis of core samples, with Se concentrations exceeding the BC water quality guideline (2.0 µg/L) in 98% of samples (n = 223). Residence time for groundwater in the overburden aquifers was determined using 3H/3He age dating (n = 3) and estimates of groundwater velocity to be less than three years across the 650 m study site. The chemistry of groundwater was compared with rock drain water samples to evaluate CIs from their source through to identified discharge locations. Linear correlation of CI concentrations with SO42- concentrations in water samples showed that Se and NO3- were conservative solutes, whereas Cd was non-conservative and may be undergoing mineral precipitation or adsorption reactions in the groundwater system. The distribution of CIs in the overburden aquifers was seasonally variable and dilution was determined to be the dominant mechanism controlling the concentrations of conservative CIs (Se, SO42- and NO3-) away from the toe of the waste rock dump and during the spring freshet. The basal alluvial aquifer downgradient of the waste rock dump was estimated to annually discharge 16% of the water and 7% of the SO42- load from the catchment

Changes in nutritional, texture, rancidity and microbiological properties of composite biscuits produced from breadfruit and wheat flours enriched with edible fish meal

The use of indigenous crops in the preparation of nutritious snacks such as biscuits has been reported as a means of alleviating the perennial problem of malnutrition among Nigerians, especially children. However, storage has been recognised as a factor affecting the attributes of these biscuits. This study investigated the quality changes of biscuit produced from fish meal enriched-composite flour of breadfruit and wheat. Freshly harvested seedless variety of breadfruit, matured catfish, wheat flour and other ingredients were procured from local outlets in Ogun State, Nigeria. Breadfruit flour (BF) was produced by washing, manual peeling, washing, grating, bagging, dewatering, pulverizing and drying. Edible fish meal (EFM) was produced by washing, eviscerating, steaming and drying Catfish. Five blends of BF, WF and EFM were obtained from the optimised solutions of the D-optimal mixture design. Samples were stored (HDPE; 28 ± 2 °C) for 12 weeks. The proximate and mineral compositions, rancidity, texture profile and microbial counts of the biscuits were determined. Data were subjected to Analysis of Variance (ANOVA) and independent sample t-test. The means from ANOVA were separated using Duncan’s Multiple Range Test at p ≤ 0.05. At the end of the storage period, the biscuit blends were significantly (p ≤ 0.05) different in moisture, protein, fat, fibre, ash, carbohydrate, calcium, iron and zinc. Increased levels of EFM in the blends led to increase in protein, fat, calcium, peroxide value (PV) and free fatty acid (FFA) value of the biscuits. At the end of the storage period, moisture increased, while fat decreased. The PV and FFA of most samples increased significantly (p ≤ 0.05) with storage, and were within the maximum permissible level. Total bacterial and mould counts also increased significantly (p ≤ 0.05) and exceeded the permissible level after 4 weeks of storage. Hence, the biscuits are suitable for consumption within 4 weeks under the investigated storage conditions

Efisiensi energi dan evaluasi keselamatan pada modifikasi penggantian katalis unit Desulfurizer di PT. Kaltim Methanol Industri (KMI), Bontang, Indonesia

A B S T R A KMetanol sebagai salah satu bahan kimia dasar dapat digunakan secara langsung sebagai campuran bahan bakar untuk internal combustion engines atau bahan baku antara (intermediate chemicals) untuk memproduksi beragam bahan kimia penting seperti formaldehyde, asam asetat, dimethyl ether (DME), dan methyl tertiary butyl ether (MTBE). PT. KMI memproduksi metanol dengan bahan baku gas alam melalui proses steam reforming. Penelitian ini bertujuan untuk mendapatkan produk yang berkualitas dan proses produksi yang efisien, dibutuhkan metana yang terbebas dari pengotor sulfur. Untuk itu diperlukan unit desulfurizer berupa fixed bed berisi katalis CoMo pada unit 010-D03 dan adsorben penjerap sulfur pada unit 010-D01. Pada tahun 2019 telah dilakukan penggantian katalis 3 in 1 yang mampu menghilangkan sulfur dalam satu tangki fixed bed (010-D01). Berdasarkan data dari logbook operasi pabrik berupa pressure drop, flowrate, suhu, dan komposisi dilakukan evaluasi penghematan energi dan keselamatan dari modifikasi ini. Penggantian katalis baru pada tangki 010-D01 yang memungkinkan tangki CoMo dioperasikan dalam kondisi kosong sehingga mengurangi pressure drop di dalam sistem. Adanya penurunan pressure drop mengakibatkan konsumsi steam pada kompresor NG menjadi berkurang sehingga didapatkan penghematan energi sebesar 379 kg/jam yang setara dengan 40913 USD/tahun atau 8545 MMBtu/tahun. Untuk menjamin keselamatan dari modifikasi, dilakukan evaluasi terhadap potensi deflagration-detonation dan api menggunakan komponen segitiga api. Berdasarkan parameter keberadaan oksigen, diagram flammability, dan autoignition temperature, modifikasi yang mengoperasikan tangki 010-D03 dalam kondisi kosong, aman dari bahaya terbentuknya api dan ledakan. Dengan demikian, modifikasi penggantian katalis dan pengosongan tangki 010-D03 terkonfirmasi meningkatkan efisiensi energi dan menghemat pemakaian sumber daya alam, sehingga mendorong aplikasi nyata sustainable development di dunia industri. Kata kunci: CoMo katalis; energi kompresi; unit desulfurizer; pressure dropABSTRACT As one of the essential chemicals, methanol can be used directly as fuel mixer for internal combustion engines or intermediate chemicals which can be utilized to produce various final chemicals such as formaldehyde, acetate acid, dimethyl ether (DME), dan methyl tertiary butyl ether (MTBE). PT. KMI produces methanol based on natural gas through steam reforming process. The study aims to get good product quality and efficient process production, the raw material of methane should be avoided from any impurities, especially sulphur. To get those target, PT. KMI installed desulfurizer unit that consist of CoMo fixed bed catalyst on 010-D03 unit and adsorbent on 010-D01 unit. As improvement on 2019, the engineer found the 3 in 1 catalyst which success to preclude the sulphur trace element in the one vessel of 010-D01 unit. Based on the logbook data from plant operation such as pressure drop, flowrate, temperature and gas composition could be performed the evaluation to minimize the energy consumption and safety level of those modification. The replacement using new catalyst (3 in 1) on the 010-D01 unit allowed the system to operate the CoMo vessel (010-D03) with empty condition that could reduce pressure drop within the system. Based on the pressure drop reducing, the consumption of steam for running the NG compressor decreased and obtained the energy saving around 379 kg of steam/hour, which was equal to 40913 USD/year or 8545 MMBtu/year. In order to ensure the safety of this modification, the evaluation of fire and deflagration-detonation potential was done using triangle diagram. Based on the availability of oxygen, flammable region and autoignition temperature, the modification of 010-D01 unit which cause the empty operation of 010-D03 unit was safe from fire and explosion hazard. Therefore, the process modification through catalyst replacement could increase energy efficiency and natural resources saving for real action of sustainable development in the industrial sector. Keyword: CoMo catalyst; compression energy; desulfurizer unit; pressure dro

INEEL Subregional Conceptual Model Report Volume 3: Summary of Existing Knowledge of Natural and Anthropogenic Influences on the Release of Contaminants to the Subsurface Environment from Waste Source Terms at the INEEL

This source-term summary document is intended to describe the current understanding of contaminant source terms and the conceptual model for potential source-term release to the environment at the Idaho National Engineering and Environmental Laboratory (INEEL), as presented in published INEEL reports. The document presents a generalized conceptual model of the sources of contamination and describes the general categories of source terms, primary waste forms, and factors that affect the release of contaminants from the waste form into the vadose zone and Snake River Plain Aquifer. Where the information has previously been published and is readily available, summaries of the inventory of contaminants are also included. Uncertainties that affect the estimation of the source term release are also discussed where they have been identified by the Source Term Technical Advisory Group. Areas in which additional information are needed (i.e., research needs) are also identified

NUCLEATION AND GROWTH BEHAVIOR OF TELLURITE-BASED GLASSES SUITABLE FOR MID-INFRARED APPLICATIONS

Optical fibers transmitting in the 2-5 μm mid-infrared (MIR) spectral region are highly desirable for a variety of military and civilian applications including super-continuum generation, infrared countermeasures (IRCM), and MIR laser sources. These new applications in the mid-infrared require novel optical materials that transmit in this window and can be fabricated into fiber. As tellurite glasses are known to have good transparency in the (NIR) region, tellurite-based glasses are the material of choice for this study due to their high linear and nonlinear refractive index, their low glass transition temperature and the ability to form them into optical fiber. This dissertation summarizes findings on tellurite-based glasses with the composition (90-x)TeO2-10Bi2O3-xZnO with x = 15, 17.5, 20 and 25 that were processed and characterized for their potential application as novel optical fibers. Different techniques were deployed for characterization purposes, which include primarily linear refractive index measurements, structural characterization using Raman spectroscopy, and nucleation and growth behaviors, among others. The viscosity of the glasses was measured using a beam bending and parallel plate viscometers. The kinetics of crystallization of the bulk glasses and fiber with x =20 were studied using a differential scanning analyzer (DTA), a hot stage XRD and an optical microscope. The influence of compositional variation on the physical, thermal and optical properties of the glasses in the TeO2-Bi2O3-ZnO family was established. The parameters such as the thermal properties, activation energy for crystallization, Johnson-Mehl-Avrami exponent, or nucleation and growth domains and rates were determined and were found to depend on the glass composition. We correlated the composition-dependent variation of these parameters to the structure of the glasses via Raman spectroscopy. Key physical, thermal, structural and optical differences were observed and quantified between bulk glasses and their corresponding core and core-clad fibers. Also reported are the processing and characterization of modified tellurite-based glass in the TeO2-Bi2O3-ZnO glass family and efforts to reduce their absorption loss due to residual hydroxyl (OH) content. We discuss the impact of this OH reduction in the tellurite network on the physical, thermal and structural properties as well as nucleation and growth behavior of bulk glass and fiber