• Energy Research
• 6. Clean water close
• 3. Good health close
• English close
• VTechWorks close

Loblolly pIne (Pinus taeda) and sweetgum (Liquidambar styraciflua) were grown in miniature stands at 7.6-cm spacings outdoors in open-top chambers (4.6 m in diameter and 3.5 m tall) for 16 months. Treatments consisted of ambient- and elevated-CO₂ , drought-stressed and well-watered, and stand type (monoculture and 50:50 replacement mixture). Gas exchange was measured monthly, growth parameters bimonthly. Loblolly pine carbon exchange rate (CER) was positive throughout the winter in all treatments and averaged 83% of summer rates. Between November 1994 and April 1995, relative crowding coefficient (RCC) of pine stem volumes increased regardless of CO₂ or water availability. RCC of pine biomass increased in droughted stands relative to well-watered stands, while RCC of sweetgum showed the opposite response. Based on these results increased atmospheric CO₂ concentrations will not affect the competitive outcomes of loblolly pine and sweetgum mixed stands: loblolly pine will continue to be more competitive on dry sites, sweetgum on wet sites. CER of loblolly pine and sweetgum, as well as soil respiration, were consistently significantly greater in elevated-C02 stands. CER in upper-canopy foliage was significantly greater than that of lower-canopy foliage for sweetgum. Loblolly pine, but not sweetgum, demonstrated a significant canopy position x CO₂ interaction, with upper-canopy CER greater only in elevated-CO₂ conditions. No consistent acclimation of CER to elevated CO₂ was statistically significant for either species, although acclimation response was stronger in sweetgum than in loblolly pine. Master of Science

Ni-rich layered oxide materials have gained significant attention due to the ongoing advances and demands in energy storage. The energy revolution continues to catapult the need for improved battery materials, especially for applications in portable electronic devices and electric vehicles. Lithium batteries are at the frontier of energy storage. Due to geopolitical concerns, there is a growing need to understand the chemistries of Co-free, Ni-rich layered oxide materials which are cost-efficient and possess increased practical capacity. The challenge to studying this class of materials is their inherent electronic and structural fragility. The fragility of these materials is facilitated by a cooperation of metal cation migration, lattice oxygen loss, and undesirable oxide cathode-electrolyte interfacial reactions. Each of these phenomena contribute to complex electrolyte decomposition pathways and oxide cathode structural distortions. Structural instability leads to poor battery performance metrics including specific capacity fading and decreased Coulombic efficiency. Electrolyte decomposition occurs at the oxide cathode surface, but it can lead to bulk electronic and structural changes, chemomechanical breakdown, and irreversible phase transformations in the material. The work in this dissertation focuses on understanding some of the chemistries associated with degradation of representative Ni-rich layered oxides, specifically LiNiO2 (LNO) and LiNixMnyCozO2 (NMC) (where x+y+z =1) materials. Chapter 1 provides a comprehensive review of the interfacial chemistries of fragile, Ni-rich layered oxide materials with carbonate-based liquid electrolytes. These reactions are key in deducing mechanistic pathways that promote thermal runaway. Uncontrollable oxygen loss and electrolyte oxidation leads to catastrophic battery fires and explosions. The chapter highlights the material properties that become perturbed during high states-of-charge which complicate the materials chemistry associated with Ni-rich layered oxides. Lastly, a few strategies to mitigate undesired, structurally detrimental reactions at the Ni-rich layered oxide cathode surface are provided in Chapter 1. To obtain the technical data detailed in this dissertation, a variety of analytical methods are employed. Chapter 2 introduces the working principles of the X-ray techniques, electron microscopy, and other quantification methods. X-ray techniques including synchrotron X-ray absorption spectroscopy (XAS), and its components XANES and EXAFS are discussed. Other X-ray techniques, including X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are additionally included. Electron microscopy techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and scanning transmission electron microscopy (STEM) are provided. Quantification methods, such as gas chromatography – flame ionization detection (GC-FID) and other electrochemical testing methods are also described. Detailed experimental information obtained using the analytical methods is provided in the technical chapters. In understanding the chemistry of Ni-rich layered oxides, exploring surface reconstruction is key. Surface reconstruction, a phenomenon caused by a collaboration between Li/Ni cation intermixing and lattice oxygen loss, is one of the major explanations for structural degradation in Ni-rich layered oxide materials. Chapter 3 explores surface reconstruction and deduces a mechanism by which lattice oxygen is loss in LiNi0.6Mn0.2Co0.2O2 (NMC622). By exploiting Li+ intercalation chemistry, the work emulates various states-of-charge to explore how delithiation impacts small, organic molecule oxidation. Benzyl alcohol serves as a good probing molecule. It is similar to an oxidizable, nonaqueous electrolytic species that undergoes oxidation at the oxide cathode surface. Structure-reactivity trends are defined to correlate electronic and structural changes, lattice oxygen loss, and small molecule oxidation. After studying a proxy molecule, a practical system is required to grasp the complexity of the cathode-electrolyte interfacial reactions that promote Ni-rich layered oxide degradation. In Chapter 4, an electrolyte stirring experiment is described. Stirring experiments provide an accelerated testing method which helps to deduce the influences of chemical electrolyte decomposition on structural degradation of LiNiO2 (LNO). X-ray techniques are used to illustrate electronic perturbations and structural distortions in the material after probing with EC/DMC w/w 3:7 LiPF6. Additionally, this dissertation chapter features a novel voltage oscillation experiment that is employed to quantify Ni-rich oxide cathode degradation at the phase transition regions. LNO has three charging plateaus – H1 ïƒ M, M ïƒ H2, and H2 ïƒ H3. The latter two plateaus have been largely associated with irreversible structural fragility in Ni-rich layered oxides. Cation intermixing and oxygen loss are two phenomena that are largely associated with decreased Li+ intercalation kinetics and increased undesired side reactions. Although researchers debate the chemical phenomenon that occur at each of the phase transitions, most agree that the H2 ïƒ H3 transition is highly influenced by irreversible lattice oxygen loss. This dissertation chapter describes the studies used to explore the electronic changes and structural distortions that accompany the voltage oscillation electrochemical testing. While Ni-rich layered oxides are largely employed as lithium battery cathodes, this class of material is unique in that it is a reducible and electronically tunable. Electronically modifiable metal oxide materials provide a unique platform to lend information to other applications, such as catalysis. There is much debate surrounding the role of metal oxides on metal nanocatalyst performance for catalytically reductive pathways. Chapter 5 discusses the method of employing LiNiO2 and other NMC materials as electronically tunable metal oxides to determine the role of the reducible metal oxide support on the gold (Au) nanocatalyst for p-nitrophenol reduction to p-aminophenol. By obtaining a continuum of nickel (Ni) oxidation states using delithiation strategies, structural-activity relationship trends are provided. Conversion rates for each of the delithiated materials was calculated using pseudo first-order kinetics. Lastly, a detailed discussion on metal oxide reducibility and its influences on key mechanistic factors, such as the induction period is included. Chapter 6 in this dissertation provides conclusions for the technical work provided. It bridges the works together and describes the overarching findings associated with the chemistries of Ni-rich layered oxide materials. This dissertation lays the foundation for future experimentation and innovation in understanding the surface chemistry of Ni-rich layered oxides. Chapter 7 provides future perspectives for each of the technical works included herein. Additionally, the final chapter includes insights toward the future of lithium batteries and other cathode chemistries. As the world navigates the energy revolution, it is important to provide global perspectives expected to catapult a sustainable future with batteries towards a greener world. Doctor of Philosophy Rechargeable lithium batteries have gained a significant surge of interest due to the ongoing demands for portable electronic devices, as well as the global trend towards electric vehicles to decrease the carbon footprint. Lithium batteries reside at the pinnacle of the energy transition. Layered oxide materials are typically employed as the cathode in Li-ion batteries. Ni-rich layered oxides have gained much interest due to their low cost and good charge/discharge capabilities. As consumers want increased charging rates and longer lifetimes, researchers struggle to optimize the balance between incorporating Ni-rich cathodes and increased safety concerns caused by cathode structural fragility. The lack of structural robustness is largely due to the surface reactivity of Ni-rich layered oxide materials. Bonding arrangements and electron transfer pathways intrinsic to this class of material increases the complexity in understanding the surface chemistry and the associated degradation pathways. Oxygen loss is the major cause of the safety issues in lithium batteries such as battery fires and explosions. To mitigate the safety concerns, it is imperative to understand the chemistries that promote organic, liquid electrolyte decomposition, electronic and structural changes, chemomechanical breakdown, and irreversible phase transformations. Each of these components leads to decreased battery performance. The work in this dissertation describes model and practical platforms to probe and understand the chemistries associated with battery performance degradation. A variety of analytical methods were utilized to determine overall structure-activity relationship trends and are highlighted in Chapter 2. Chapters 3-5 is technical research providing insight on Ni-rich layered oxide degradation pathways and behaviors. The work advances the understanding of battery surface chemistry which will lead to improved cathode design. As batteries continue to grow, it is important to know other applications that benefit from the unique chemistry of Ni-rich layered oxide materials. By exploiting the lithium battery cathode chemistry, this dissertation highlights a method to utilize these materials to understand the role of metal oxides on Au nanocatalysts. Conclusions to the findings in this dissertation are provided in Chapter 6. Future perspectives on the technical research provided herein this dissertation is included in Chapter 7. Additionally, Chapter 7 details future perspectives for lithium batteries and how they can facilitate the global transition toward a sustainable future.

The use of anthracite as a filter medium is gaining popularity throughout industry as evidenced by the fact that in recent years 1100 filter plants have been installed for clarifying water and other chemicals (51). Since little information is contained in the literature as to why anthracite has become so popular replacing the much used sand filters, this investigation was undertaken in an effort to determine the reason, if any, tor this popularity of use. A number of factors such as rank, chemical composition, size, shape, and surface condition or coal could possibly affect its adsorptive properties. Tests were made in an effort to determine if any relationship existed between these factors and adsorptive properties. In the experiments tannin extract solution and viscose spinning bath solution were used as the adsorbate and coals varying in rank from anthracite to high volatile bituminous C, in sizes of -4 +8, -8 +10, -8 +16, -10 +16, -16 +20, -20 +30, and -30 +40, as the adsorbent. The tests were made with the coal in the form of the conventional filter bed (10 ± l in. depth) in l¼ diameter by 12" length Liebig condenser jackets with the direction of flow of the adsorbate, in the case of the tannin extract solution in an upward direction, at a rate of coverage of 500 to 2600 cm.²/min., at 24 ± 4°C, and the viscose spinning bath solution in a downward direction, at a velocity of 19 to 44 ml./min., at 35 ± 6°C. The results of the experiments indicated that in the case of the tannin extract solution the coals were not effective to tannin extract solution clarification; while in the case of the viscose spinning bath solution the following conclusions were drawn: l. As the size of anthracite was decreased from -4 .+8 to -30 +40 mesh (U. S. Standard Screen), thus decreasing the pore space diameter and increasing the surface area in the coal bed from 2740cm.², to 22,940 cm.², the amount of insoluble solids adsorbed was increased from 10.3 p.p.m. or 27.9% to 34.1 p.p.m. or 92.4% of insoluble solids in the testing solution. 2. In testing all coals in the size range of -8 +16 mesh (U. S. Standard Screen), the solids adsorbed per 1000 cm.² of coal surface increased from 9.7% to 14.7% as the porosity of the coal beds decreased from 52.3% to 47.2%. 3. In testing all coals in the size range of -8 +16 mesh (U. S. Standard Screen), no correlation of proximate chemical analysis or relative roughness with adsorptive power could be obtained. 4. The method of determining surface area used in this investigation is a satisfactory means of obtaining relative external surface area of coal particles of the sizes tested. Master of Science

Metadata only record Conventional tillage with plow disks and harrows leaving bare soil must no longer be considered recommended practice. Continuous no-till, maintaining soil cover with plant residues, called Conservation Agriculture (CA) must become the standard practice used by agriculture. Initially, more fertilizer may be required, but, as soil organic carbon (SOC) increases, the soil becomes more productive, requiring the same or even less fertilizer due to the increased values of nitrogen, phosphorus, potassium, calcium, magnesium and also greater pH and cation exchange capacity. Soil cover protects the soil against the impact of raindrops, prevents the loss of water from the soil through evaporation, and also protects the soil from the heating effect of the sun. Good aggregation, abundant surface crop residue, and a biologically active soil are keys to drought-proofing a soil. The utilization of CA with permanent soil cover not only improves soil and water quality for the farmer, but also improves the environment for all. CA has experienced wide application and levels of farmer acceptance on more than 100 million ha worldwide and is gaining even greater interest due to demonstrated increases in production, profitability and sustainability. In order to be successful, practicable, and fail-proof and to achieve widespread adoption of CA, farmers require an adequate level of knowledge to ensure that all aspects of the no-till production system are being considered.

"The State of Food and Agriculture 2007 highlights the potential of agriculture for enhanced provision of ecosystem services that are not usually compensated for by the market. When we think of farmers, we typically think of the food and fibre that they produce and that they either consume or sell on markets to generate an income. But the production processes can also result in impacts on other ecosystem services that are not traded in markets, referred to in this report as 'environmental services'. Some may be positive, such as groundwater recharge and scenic landscapes; others may be negative, such as water pollution by plant nutrients and animal waste, and soil erosion from poorly managed croplands or overgrazed hillsides. As agricultural production expands, these negative effects can develop into increasingly serious problems. A fundamental question concerns how farmers can be encouraged to reduce negative side-effects while meeting the growing demands for food and fibre. At the same time, changes in agricultural practices may also contribute to addressing environmental problems generated outside agriculture, for example, by offsetting greenhouse gas emissions from other sectors. A relevant question, therefore, is how farmers can be induced to increase their provision of this type of service. PES-1 (Payments for Environmental Services Associate Award)

Though the virus has led to new social distancing measures and disinfecting procedures, some hotels maintain their perspective for staying sustainable by getting rid of printed materials like menus or guest books. Hilton implemented several initiatives to reduce the uses of plastics in the process of hotel operation. This is not for the profit but for the entire people caring for their employees and the local environment as well.

The presentation shows the International Development Enterprises' low cost drip irrigation system with an application in Cambodia. LTRA-5 (Agroforestry and Sustainable Vegetable Production)

In 1971, Garrett Hardin published an editorial entitled _Nobody Ever Dies of Overpopulation based on the cyclone that struck East Bengal and killed an estimated 500,000 people. Overcrowding forced people to live in a dangerous place like the Gangetic Delta which is barely above sea level. Now, 37 years later, a similar situation is unfolding in the Ganges River Delta in Bangladesh. This delta is also barely above sea level, and the water keeps rising due to global warming. If a large storm were to create hurricanes in this area housing and agricultural areas would be destroyed as well as power lines and water supply which would interfere with food deliveries and medical assistance. In a worst case scenario environmental refugees could reach 25 million and the death toll could be in the millions. If global climate change was one of the antecedent causes to this worst case scenario, would seal level rise and sever weather truly be the cause of deaths?

The response of plants to environmental stress spans several orders of magnitude in time and space, causing system-wide changes. These changes comprise of both protective responses and adverse reactions in the plant. Stresses like water deficit or drought cause a drastic effect in crop yield, while concomitantly agriculture consumes 1/3rd of the fresh water available to us and there is widespread water scarcity around the world. It is, hence, a fundamental goal of modern biology and applied biotechnology to unravel this complex stress response in laboratory model plants like Arabidopsis and crop models like rice. Such an understanding, especially at the cellular level, will aid in informed engineering of stress tolerance in plants. We have developed and used integrative functional genomics approaches to characterize environmental stress response at various levels of organization including genes, modules and networks in Arabidopsis and rice. We have also applied these methods in problems concerning bioenergy. Since the poor knowledge of the cellular roles of a large portion of plant genes remains a fundamental barrier to using such approaches, we have further explored the problem of 'gene function prediction'. And, finally, as a contribution to the community, we have curated a large mutant resource for the crop model, rice, and established a web resource for exploratory analysis of abiotic stress in this model. All together, this work presents insights into several facets of stress response, offers numerous novel predictions for experimental validation, and provides principled analysis frameworks for systems level analysis of environmental stress response in plants. Ph. D.

Metadata only record Two distinctive features seem to be driving the agricultural sector in Morocco. The first appears to be an increased frequency of drought, with six of ten years in the 1990s characterized as drought years. The second is the continued protective policy that the government maintains on strategic agricultural commodities, primarily cereals. We employ an enhanced general equilibrium model that examines the long run impacts of trade liberalization policy under alternative climate outcomes. Our results indicate that returns to factors of production are bid up under favorable climate and decline dramatically in the bad state of nature. This behavior is transmitted to households welfare. With complete wheat trade liberalization, we find that landowners are the primary losers irrespective of the state of nature realized. The urban sector gains. There is also evidence that livestock capital mitigates the negative impacts of liberalization in the event of drought, especially for small farmers.