Method to obtain nonuniformity information from field emission behavior

Copyright © 2010 American Vacuum Society / American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Vacuum Science and Technology Part B: Microelectronics and Nanometer Structures, 28(3), Article number 441 and may be found at http://scitation.aip.org/content/avs/journal/jvstb/28/3/10.1116/1.3327928.This article describes the characterization of field emission from a planar cathode to a spherical anode with the approach curve method (ACM). In such a diode configuration the electric field strength at the cathode surface is nonuniform. This nonuniformity gives an extra degree of freedom and it allows the interpretation of the current-voltage and voltage-distance (V×d) curves in terms of nonuniformity. The authors apply the ACM to Cu emitters to explain the nonlinearity of the V×d curve in ACM measurements. This analysis provides a good insight into field emission phenomena, supporting a method for nonuniformity characterization based on field emission behavior

A soil column study to evaluate treatment of trace elements from saline industrial wastewater

Citation: Paredez, J. M., Mladenov, N., Galkaduwa, M. B., Hettiarachchi, G. M., Kluitenberg, G. J., & Hutchinson, S. L. (2017). A soil column study to evaluate treatment of trace elements from saline industrial wastewater. Water Science and Technology. https://doi.org/10.2166/wst.2017.413Industrial wastewater from the flue gas desulfurization (FGD) process is characterized by the presence of trace elements of concern, such as selenium (Se) and boron (B) and relatively high salinity. To simulate treatment that FGD wastewater undergoes during transport through soils in subsurface treatment systems, a column study (140-d duration) was conducted with native Kansas soil and saline FGD wastewater, containing high Se and B concentrations (170 ?g/L Se and 5.3 mg/L B) and negligible arsenic (As) concentration (?1.2 ?g/L As). Se, B, and As, and dissolved organic carbon concentrations and organic matter spectroscopic properties were measured in the influent and outflow. Influent Se concentrations were reduced by only ?half in all treatments, and results suggest that Se sorption was inhibited by high salinity of the FGD wastewater. By contrast, relative concentrations (C/Co) of B in the outflow were typically 150 ?g/L in the treatment with labile organic carbon addition) suggest that soils not previously known to be geogenic arsenic sources have the potential to release As to groundwater in the presence of high salinity wastewater and under reducing conditions

Alignment between PIN1 Polarity and Microtubule Orientation in the Shoot Apical Meristem Reveals a Tight Coupling between Morphogenesis and Auxin Transport

Morphogenesis during multicellular development is regulated by intercellular signaling molecules as well as by the mechanical properties of individual cells. In particular, normal patterns of organogenesis in plants require coordination between growth direction and growth magnitude. How this is achieved remains unclear. Here we show that in Arabidopsis thaliana, auxin patterning and cellular growth are linked through a correlated pattern of auxin efflux carrier localization and cortical microtubule orientation. Our experiments reveal that both PIN1 localization and microtubule array orientation are likely to respond to a shared upstream regulator that appears to be biomechanical in nature. Lastly, through mathematical modeling we show that such a biophysical coupling could mediate the feedback loop between auxin and its transport that underlies plant phyllotaxis

King Kong in the Bronx

Mexican American Studie

Supplementation of the Community Action Board of Santa Cruz County’s Commitment to Equity

The Community Action Board of Santa Cruz County, Inc. (CAB) is a non-profit organization that aids low-income clients with emergency, sustaining, and self-sufficiency services through their specialized program areas. Through a micro-level assessment of the County, research indicates a growing rate of poverty among marginalized communities, particularly in the Latinx population. Inequities relating to the low-wage occupational outlook in highly populated Latinx communities coupled with a high unemployment rate in Santa Cruz County only exacerbate the cyclical issue of poverty. Among marginalized community members who are most affected, they are also faced with housing insecurity and lack of health insurance. This project is centered around CAB’s commitment to equity. As service providers tasked with dismantling inequities with culturally grounded and relevant interventions to the diverse community, cultural competency is essential. The project implementation of an intern co-facilitated Equity Academy for staff along with an Equity Library shelved with literature recommendations from the community will help supplement staff\u27s knowledge of equity, social justice, and cultural competence when working with vulnerable populations in the County. Findings concluded positive participant feedback from the Equity Academy with new perspectives on the term “equity” and what it means for the community they serve. Recommendations for the future include: a continued facilitation of Equity Academy classes with an increased number of participants and adding additional literature and materials that relate to CAB’s core value of equity to their new library

Brotamiento y compuestos bioactivos de tres variedades de oca (Oxalis tuberosa) en almacenamiento postcosecha

During postharvest storage oca tubers can pass for different stages, in which bioactive compounds can change their content; and specifically the sprouting stage, can alter significatively these components. Therefore, this study evaluated the sprout length, loss weight, reducing sugar content, total phenolics content, and antioxidant capacity of three oca tuber varieties (yellow, purple, and orange) during postharvest storage. Oca tuber varieties were stored at 19 °C ±1 ºC and relative humidity of 85% ±1%. A factorial design was used to evaluate the effect of oca variety and postharvest storage time (0, 15, 30, 45, 60, 75, and 90 days). The sprout length of the three oca varieties begin to growth at 15-30 days of postharvest storage, which indicated that dormancy period was broken, moreover, the sprout length was increased until 90 days of storage. Yellow oca had the longest sprout length (26.4 cm) and the highest loss weight (22.55 %) at 90 days of storage, which indicated an effect of oca variety and postharvest storage time (p value≤0.05). The reducing sugar content, total phenolics content, and antioxidant capacity of the three oca varieties exhibited variable behaviors during storage time and initially oca tubers showed a reduction in their values, which were presumably related to the stabilization period. The postharvest storage time and oca variety produced different physiological changes in the oca tubers, which affect the sprout length, weight loss, reducing sugars, total phenolics content, and antioxidant capacity.Durante el almacenamiento postcosecha los tubérculos de oca pueden pasar por diferentes etapas, en las cuales los compuestos bioactivos pueden cambiar su contenido y específicamente la etapa de brotación puede alterar significativamente estos componentes. Por lo tanto, este estudio evaluó la longitud de los brotes, la pérdida de peso, el contenido de azúcares reductores, el contenido de fenólicos totales y la capacidad antioxidante de tres variedades de tubérculos de oca (amarilla, morada y naranja) durante el almacenamiento poscosecha. Las variedades de tubérculo de oca se almacenaron a 19 °C ±1 ºC y una humedad relativa de 85% ±1%. Se utilizó un diseño factorial para evaluar el efecto de la variedad de oca y el tiempo de almacenamiento poscosecha (0, 15, 30, 45, 60, 75 y 90 días). La longitud de los brotes de las tres variedades de oca comenzó a crecer a los 15-30 días de almacenamiento poscosecha, lo que indicó que se rompió el período de latencia, además, la longitud de los brotes se incrementó hasta los 90 días de almacenamiento. La oca amarilla tuvo la longitud de brote más larga (26,4 cm). y la mayor pérdida de peso (22,55 %) a los 90 días de almacenamiento, lo que indicó un efecto de la variedad de oca y el tiempo de almacenamiento poscosecha (p valor≤0,05). El contenido de azúcares reductores, el contenido de fenólicos totales y la capacidad antioxidante de las tres variedades de oca exhibieron comportamientos variables durante el tiempo de almacenamiento e inicialmente los tubérculos de oca mostraron una reducción en sus valores, los cuales presumiblemente estuvieron relacionados con el período de estabilización. El tiempo de almacenamiento poscosecha y la variedad de oca produjeron diferentes cambios fisiológicos en los tubérculos de oca, que afectan la longitud de los brotes, la pérdida de peso, los azúcares reductores, el contenido de fenólicos totales y la capacidad antioxidante

Genetic evidence that cellulose synthase activity influences microtubule cortical array organization

To identify factors that influence cytoskeletal organization we screened for Arabidopsis ( Arabidopsis thaliana) mutants that show hypersensitivity to the microtubule destabilizing drug oryzalin. We cloned the genes corresponding to two of the 131 mutant lines obtained. The genes encoded mutant alleles of PROCUSTE1 and KORRIGAN, which both encode proteins that have previously been implicated in cellulose synthesis. Analysis of microtubules in the mutants revealed that both mutants have altered orientation of root cortical microtubules. Similarly, isoxaben, an inhibitor of cellulose synthesis, also altered the orientation of cortical microtubules while exogenous cellulose degradation did not. Thus, our results substantiate that proteins involved in cell wall biosynthesis influence cytoskeletal organization and indicate that this influence on cortical microtubule stability and orientation is correlated with cellulose synthesis rather than the integrity of the cell wall

Identificación de factores para reducir accidentes por desprendimiento de rocas en minería subterránea

The objective of the present study is to identify factors to reduce accidents in mining or other underground excavations, caused by rockfall. To achieve this purpose, the fatal accidents that occurred from 2001 to 2011 were investigated in the prime sources, among others, MINEM, the Ministry of Labor and Employment Promotion and OSINERGMIN. From the information compiled and processed, the corresponding analysis was performed, thus identifying the following factors: a) Type of rock. 87% of fatal accidents occurred in type III and IV rocks. b) Type of support. 45.8% of fatal accidents occurred in unsupported areas and in areas sustained with wood, Split Set and Helical Bars occurred 45.85%. c) Type of work. 59% of fatal accidents occurred in hacking. d) Occupation. 53% of fatal accidents suffered drilling master and / or assistants. e) Work shift. 58% of fatal accidents occurred in day shifts. f) Hours of the day. 41.4% of fatal accidents occurred between 9: 00-12: 00 and 15: 00-18: 00. g) Service time. 54.3% of fatal accidents suffered workers with less than one year of service.El objetivo del presente estudio es identificar factores para reducir accidentes en las labores mineras u otras excavaciones subterráneas, ocasionados por desprendimiento de rocas. Para alcanzar tal propósito, se investigó los accidentes mortales ocurridos de 2001 a 2011, en las fuentes primigenias, entre otras, MINEM, Ministerio de Trabajo y Promoción del Empleo y OSINERGMIN. A partir de la información compilada y procesada, se realizó el análisis correspondiente, así se identificaron los siguientes Factores a) Tipo de roca. El 87 % de accidentes mortales se produjeron en rocas tipo III y IV. b) Tipo de sostenimiento. El 45,8 % de los accidentes mortales se produjeron en áreas no sostenidas y en áreas sostenidas con madera, Split Set y Barras Helicoidales se produjeron el 45,85 %. c) Tipo de labor. El 59 % de los accidentes mortales se produjeron en los tajeos. d) Ocupación. El 53 % de los accidentes mortales sufrieron maestros perforistas y/o ayudantes. e) Turno de trabajo. El 58 % de accidentes mortales ocurrieron en turnos de día. f) Horas del día. El 41,4 % de accidentes mortales se produjeron entre las 9:00-12:00 horas y 15:00-18:00 horas. g) Tiempo de servicio. El 54,3 % de accidentes mortales sufrieron trabajadores con menos de un año de servicio

Coal-fired power plant flue gas desulfurization wastewater treatment using constructed wetlands

Master of ScienceDepartment of Civil EngineeringNatalie MladenovIn the United States approximately 37% of the 4 trillion kWh of electricity is generated annually by combusting coal (USEPA, 2013). The abundance of coal, ease of storage, and transportation makes it affordable at a global scale (Ghose, 2009). However, the flue gas produced by combusting coal affects human health and the environment (USEPA, 2013). To comply with federal regulations coal-fired power plants have been implementing sulfur dioxide scrubbing systems such as flue gas desulfurization (FGD) systems (Alvarez-Ayuso et al., 2006). Although FGD systems have proven to reduce atmospheric emissions they create wastewater containing harmful pollutants. Constructed wetlands are increasingly being employed for the removal of these toxic trace elements from FGD wastewater. In this study the effectiveness of using a constructed wetland treatment system was explored as a possible remediation technology to treat FGD wastewater from a coal-fired power plant in Kansas. To simulate constructed wetlands, a continuous flow-through column experiment was conducted with undiluted FGD wastewater and surface sediment from a power plant in Kansas. To optimize the performance of a CWTS the following hypotheses were tested: 1) decreasing the flow rate improves the performance of the treatment wetlands due to an increase in reaction time, 2) the introduction of microbial cultures (inoculum) will increase the retention capacity of the columns since constructed wetlands improve water quality through biological process, 3) the introduction of a labile carbon source will improve the retention capacity of the columns since microorganisms require an electron donor to perform life functions such as cell maintenance and synthesis. Although the FGD wastewater collected possessed a negligible concentration of arsenic, the mobilization of arsenic has been observed in reducing sediments of wetland environments. Therefore, constructed wetlands may also represent an environment where the mobilization of arsenic is possible. This led us to test the following hypothesis: 4) Reducing environments will cause arsenic desorption and dissolution causing the mobilization of arsenic. As far as removal of the constituents of concern (arsenic, selenium, nitrate, and sulfate) in the column experiments, only sulfate removal increased as a result of decreasing the flow rate by half (1/2Q). In addition, sulfate-S exhibited greater removal as a result of adding organic carbon to the FGD solution when compared to the control (at 1/2Q). Moderate selenium removal was observed; over 60% of selenium in the influent was found to accumulate in the soil. By contrast, arsenic concentrations increased in the effluent of the 1/2Q columns, most likely by dissolution and release of sorbed arsenic. When compared to the control (at 1/2Q), arsenic dissolution decreased as a result of adding inoculum to the columns. Dissolved arsenic concentrations in the effluent of columns with FGD solution amended with organic carbon reached 168 mg/L. These results suggest that native Kansas soils placed in a constructed wetland configuration and amended with labile carbon do possess an environment where the mobilization of arsenic is possible