Angular Distribution of Bremsstrahlung Produced by 10-keV and 20-keV Electrons Incident on a Thick Au Target

The relative intensities of the thick-target bremsstrahlung produced by 10-keV and 20-keV electrons incident on Au at forward angles ranging from 0 degrees to 25 degrees are compared. Following corrections for photon absorption within the target, the detected radiation appears to be distributed anisotropically only for photon energies, k, that are approximately equal to the initial energy of the incident electrons, E. The results are compared to the theoretical angular distributions of Kissel et al. [At. Data Nucl. Data Tables 28, 381 (1983)]. The comparison suggests that when k/E is approximately equal to 1, the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the theoretical angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets.Comment: The following article has been accepted by AIP Conference Proceedings (Vol. 1525). After it is published, it will be found at http://proceedings.aip.org

Analysis of ZDDP content and thermal decomposition in motor oils using NAA and NMR

Zinc dialkyldithiophosphates (ZDDPs) are one of the most common anti-wear additives present in commercially-available motor oils. The ZDDP concentrations of motor oils are most commonly determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES). As part of an undergraduate research project, we have determined the Zn concentrations of eight commercially-available motor oils and one oil additive using neutron activation analysis (NAA), which has potential for greater accuracy and less sensitivity to matrix effects as compared to ICP-AES. The 31P nuclear magnetic resonance (31P-NMR) spectra were also obtained for several oil additive samples which have been heated to various temperatures in order to study the thermal decomposition of ZDDPs.Comment: Manuscript has been accepted for publication in Physics Procedia as part of the proceedings of the 23rd International Conference on Application of Accelerators in Research and Industry (CAARI 2014

Synthetic Studies Of (+)-Nodulisporic Acid A: Development Of An Efficient Route To Eastern Hemisphere Sub-Targets

(+)-Nodulisporic Acid A (NsAA) is an indole diterpene of complex structure, isolated from the fungus nodulisporium sp., possessing potent insecticidal activity. Herein is described a new tactic for the construction of complex indoles employing a tandem palladium-mediated process between a haloindoline and a vinyl bromide or triflate. Chapter 1 of this work will review the efforts by Merck and Co. that lead to the isolation and discovery of potent analogs of NsAA, as well as briefly review the history of complex indole synthesis in the Smith Research Group. Chapter 2 will describe efforts to streamline the synthesis of the chiral, non-racemic material used to make different variants of the eastern hemisphere sub-target, the development of a new tactic for bringing the two hemispheres together, and efforts to synthesize an eastern hemisphere sub-target that contains the sidechain of NsAA

Daet AirWatch: A Framework for Measuring and Visualizing Air Pollution Levels in Daet, Camarines Norte

Air pollution presents serious threats to public health and the environment, thus, effective techniques for mitigation and monitoring are required. In this study a comprehensive framework that integrates low-cost sensors, GPS technology, and data processing using an Arduino Uno and an ESP8266 Wi-Fi module is presented to address air pollution. The proposed framework allow real-time collection of pollutant data, including (PM), (VOCs), (CO), and ozone, alongside location information, temperature, and humidity. The gathered data is subjected to thorough processing, which includes converting sensor output values and calibrating and normalizing raw sensor readings. Moreover, the framework includes algorithms for translating pollutant concentrations into Air Quality Index (AQI) values, giving standardized metrics for evaluating air quality levels. The data is processed and then sent to an MQTT Broker for quick sharing of information and alerting about dangerous conditions. Additionally, the platform includes a user-friendly interface that displays pollution data on a web map, improving transparency and community awareness. By utilizing its effective data collection, processing, and visualization features, the suggested framework seeks to enhance public health results by giving people and communities the ability to make informed choices and take proactive steps to reduce air pollution dangers

Rhegmatogenous retinal detachment masquerading as exudative panuveitis with intense anterior chamber inflammatory reaction.

Purpose:This is a retrospective case report illustrating the diagnostic and therapeutic challenges associated with a chronic rhegmatogenous retinal detachment masquerading as a severe panuveitis with intense anterior chamber inflammation. We have included clinical features, anterior segment and fundus photography, B-scan ultrasonography, fluorescein angiography, and intraoperative findings. Observations:A 26-year-old male presented with features of unilateral panuveitis: hypotony, anterior segment inflammation (posterior synechiae and anterior chamber cell with fibrin clumping), diffuse choroidal thickening, and retinal detachment. Laboratory investigations for infectious or rheumatologic processes were negative, and empiric systemic corticosteroid therapy was unsuccessful. This prompted suspicion for an alternate primary etiology, and pars plana vitrectomy revealed small retinal breaks as the underlying cause of the retinal detachment and inflammation. Conclusions:Rhegmatogenous retinal detachments are a known cause of intraocular inflammation. Nevertheless, it remains a challenge to recognize retinal breaks in this setting, particularly with robust anterior segment inflammation and posterior findings resembling severe exudative uveitis. Being aware of this unique presentation may prevent delays in diagnosis and have important prognostic implications

The potential role of kelp forests on iodine speciation in coastal seawater

Funding: FCK would like to thank the TOTAL Foundation (Paris) and the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) for their support. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. JG acknowledges support from an SDSU Research Foundation Summer Undergraduate Research Award. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Sediment yield in Salmon Creek after decommissioning logging roads, Northern Humboldt County, California

Salmon Creek watershed is located in the Headwaters Forest Reserve in northern California and is known for the ecological value of its old-growth redwood forest, high biodiversity, and sensitive habitat for endangered species. The Bureau of Land Management primarily manages the Reserve. The land-use history of the Upper Salmon Creek watershed includes extensive timber harvest and road development. Watershed restoration in the Upper Salmon Creek watershed started in 2000 with the primary goal for the Reserve to protect and recover ecologic diversity and threatened native species. Since then, of the 23 miles, 13.5 miles of logging roads and 101 stream crossings have been decommissioned and treated, with 2 miles maintained, 2.4 miles passively restored, and 5.1 miles still requiring assessment. The restoration work is focused on long term reduction in sediment delivery from erosional sites that have historically degraded water quality in the Salmon Creek watershed. A stream monitoring station is located in the Upper Salmon Creek watershed that uses a turbidity threshold sampling protocol based on turbidity, stage, and temperature. The objective is to evaluate the data collected from Water Year (WY) 2012 to 2019 to assess the sediment yield in the watershed. The field and laboratory data collected at the stream monitoring station were used to further understand the relationships between hydrology, sediment transport, and land-use, and to estimate sediment load from WY 2012 to 2019. Additionally, two precipitation-monitoring stations were installed in the Upper Salmon Creek watershed during WY 2019, to provide a more spatially representative rainfall data set. Discharge rating curves and turbidity-sediment rating curves were developed to estimate continuous discharge and suspended sediment concentration (SSC) at the stream monitoring station, which were then used to estimate annual sediment yield. The annual sediment yield from WY 2012 to 2019 ranged from 9 tons/mi2 to 178 tons/mi2 (49 tons to 944 tons). The discharge rating curves need to be established every year due to periodic geomorphic changes in the channel cross-section at the monitoring station. However, the relationship between turbidity and SSC does not appear to change from year to year, and the existing data that was collected is adequate to quantify the relationship between turbidity and SSC. The exception is at high values of turbidity, where it is recommended to reprogram the automated sampler to draw water samples only at the very highest turbidity thresholds to refine the relationship with SSC. On average, storms were responsible for 77% of the total annual sediment yield over the period of record. Annual sediment yield varied from year to year, and seemed to be strongly influenced by the characteristics of individual storms within a WY such as rainfall intensity in the watershed. Additionally, episodic events such as bank failures and landslides may have elevated turbidity and discharge. Estimating sediment load by individual storm events is the first step in exploring the meteorological, hydrological, and other temporal changes that contribute to variability in sediment transport and sediment load. Future studies should focus on normalizing the data to effectively remove the interannual variability in sediment yield that is related to rainfall variability and episodic events so that trends in sediment yield that may be due to land use changes and restoration actions can be identified