5,890 research outputs found

    Investigation of Energy Consumption and Characteristics of a Battery Electric Vehicle

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    Electric vehicles are becoming more popular for manufacturers as emissions restrictions for internal combustion engine (ICE) powered vehicles become tighter. The primary objective of this study was to characterize a battery electric vehicle (BEV) with respect to energy consumption as well as emissions from the battery or propulsion system. It was also desired to compare the BEV to internal combustion engine (ICE) powered vehicles in its class considering greenhouse gases, as well as energy economy, miles per gallon (MPG), and miles per gallon equivalent (MPGge) efficiency.;Tesla is a forerunner in BEVs. The approach they took in making their battery pack is different from any other BEV manufacturer. The Tesla battery pack or energy storage system (ESS) is constructed out of thousands of 18650 style lithium ion battery cells through a partnership with Panasonic. The tooling for these battery cells was already established which keeps costs down. This unique design allows Tesla to have one of the cheapest ESS cost per kilo-watt-hour of any manufacturer.;A 2013 Tesla Model S P85 was exercised on a chassis dynamometer along with on road testing consisting of a CAFEE Morgantown Route and Bruceton Mills Route to characterize its energy consumption. Energy consumption data was measured with a current clamp on the positive high voltage battery cable and voltage probes contacting the high voltage busbar. Vehicle speed was recorded from the chassis dynamometer and a global positioning system (GPS) when operating the vehicle on-road.;Battery electric vehicles do not have a tailpipe and thus do not produce tailpipe emissions like an internal combustion engine powered vehicle does. However; it was desired to investigate if the ESS or propulsion system emitted any gases. A sample manifold was fabricated to mount to the battery pack vent. Samples were taken with and without a sample pump during charging, highway driving, and dynamometer testing. These samples were analyzed with a Fourier transform infrared (FTIR) analyzer and a gas chromatograph (GC) analyzer.;A bench top experiment was devised in an attempt to determine the source of the gases emitted from the vehicle\u27s ESS. Six Tesla 18650 style battery cells were purchased and installed into a test rig. These cells were then charged and discharged to determine if there was any gases emitted from the cells themselves. Exercising the battery cells outside of the ESS did not produce any of the emissions observed while examining the ESS on the vehicle. Through these experiments it was concluded that the gases emitted from the ESS on the vehicle were a result of damaged cells or deterioration of other construction materials. Furthermore, it was also possible that the ESS was acting as a thermal pump due to ambient temperature changes within the ESS

    Anthropogenic Impacts on Wildlife Mortality and Vertebrate Scavenging Communities

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    Roads cause substantial wildlife mortality, but there is currently limited understanding of the relative magnitude of this mortality source. There are also substantial gaps in knowledge concerning the ecological ramifications of carrion introduced to the environment from vehicle collisions and in particular how vertebrate scavengers may consume carrion resulting from vehicle collisions. Although a variety of factors influence scavenger use of carcasses, the mechanisms influencing competition for this resource between obligate and facultative scavengers have not been thoroughly explored. I conducted a global synthesis of mortality of terrestrial vertebrates documenting 42,755 mortalities of known cause from 120,657 individuals representing 305 vertebrate species. Overall, 28% of mortalities were directly caused by humans and 72% were from natural sources. Vehicle collisions accounted for 4% of mortality overall. Larger birds were more likely than smaller birds to die from vehicle collisions and vehicle mortality of mammals increased over time. There was no difference in proportion of rabbit carcasses scavenged or scavenger arrival time between those placed along roads, power line clearings, and forests. No species arrived at roads quicker than other treatments. Turkey vultures (Cathartes aura) and coyotes (Canis latrans) scavenged equally across treatments, whereas gray foxes (Urocyon cinereoargenteus) scavenged along roads and power lines, but not in forests. Scavenger use of carrion near roads likely relates to factors besides carrion availability, such as traffic avoidance and predation risk. Because some scavengers make substantial use of carrion on roads, this resource could be an important mechanism by which human activities impact wildlife. Scavenging by facultative scavengers did not increase in the absence of competition with vultures. I found no difference in scavenger presence between control carcasses and those from which vultures were excluded. Facultative scavengers did not functionally replace vultures during summer in this study. These results suggest that under the conditions of this study, facultative scavengers would not compensate for loss of vultures. Carcasses would persist longer in the environment and consumption of carrion would likely shift from vertebrates to decomposers. Such changes could have substantial implications for disease transmission, nutrient cycling, and ecosystem functioning

    An analysis of the methods of subtraction in a school system

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    Thesis (M.A.)--Boston University, 1937. This item was digitized by the Internet Archive

    CNC spindle signal investigation for the prediction of cutting tool health

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    The deterioration of cutting tools plays a significant role in the progression of subtractive manufacturing and substantially affects the quality of machined parts. Recognising this most organisations have implemented conventional methods for tool management. These reduce the economic loss associated with time-dependent and stochastic tool wear, and limit the damage arising from tools at end-of-life. However, significant costs still remain to be addressed and more development towards tool and process prognostics is desirable. In response, this work investigates process deterioration through the acquisition and processing of selected machine signals. This utilises the internal processor of a CNC Vertical Machining Centre and considers the possible applications of such an approach for the prediction of tool and process health. This paper considers the prediction of tool and process condition with a discussion of the assumptions, benefits, and limitations of such approaches. Furthermore, the efficacy of the approach is tested using the correlation between an offline measurement of part accuracy and an active measure of process variation

    Reflections on Frankfort Rally

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    Comments on Frankfort rally

    Absenteeism at Work

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    As the economic side of the world continues to grow, so do the demands associated with it. In lieu of these demands, absenteeism at work can lead to interruptions throughout a company or with a company’s workflow. The overarching question is, can these be predicted despite being unintentional or habitual? Excessive absences impact the performance of the company and the individual. One guarantee is these absences can derive from a variety of reasons, whether medical or personal. Another factor in absences require looking into personal lives, work load, distance from work. By using the Absenteeism at Work from UCI Machine Learning Repository, we will attempt to build a machine learning model using Python. From this data set and this research, we demonstrate an ability to predict absentee time based on the reason for the absence, while accounting for the general lifestyle of the employee(s). We intend to  evaluate the impacts of the absenteeism on the company and how to bridge the gaps left when a worker is missing. We hypothesize that employees with more severe medical issues will be at the upper range of all absences, and employees with more social occupations are more likely to miss than their less social counterparts. Using R’s modeling capabilities, we present various statistical and graphical observations

    Intensive Archaeological Survey of the Proposed Casa Bella Estates Land Development Project and Data Recovery at Site 41BX2131, San Antonio, Bexar County, Texas

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    At the request of Matiraan, Ltd., Pape‐Dawson conducted an intensive archaeological survey with shovel testing and backhoe trenching of the proposed 37‐acre (15‐hectare [ha]) Casa Bella Estates residential development in compliance with the Historic Preservation and Design Section (Article 6 35‐360 to 35‐ 634) of the City of San Antonio (COSA) Unified Development Code (UDC). Based on the results of those investigations, the COSA Office of Historic Preservation (SA‐OHP) requested further work to mitigate the effects of the proposed development on a potentially significant archaeological site (41BX2131). Subsequently, data recovery investigations were accomplished at site 41BX2131. This report documents all phases of fieldwork. The Casa Bella Estates residential development is within the COSA city limits at the confluence of Mud and Elm Waterhole Creeks in northern Bexar County, about 1.40 miles (2.25 kilometers [km]) southwest of the intersection of Bulverde Road and Loop 1604. The irregularly shaped project area straddles an existing driveway that provides access to Jones Maltsberger Road. The development would be maximally about 1,739 feet (ft) (530 meters [m]) north to south, and 2,264 ft (690 m) east to west. The vertical impacts for the proposed development have not yet been determined. Compliance with the Antiquities Code of Texas or Section 106 of the National Historic Preservation Act is not required because the project is on private property and does not involve federal funding or permitting. However, based on the Archaeological Report Guidelines of the SA‐OHP, any observed cultural resources were to be evaluated according to the criteria in Title 36 Code of Federal Regulations Part 60.4 (36 CFR 60.4) and in Title 13 Texas Administrative Code Chapter 26.10 (13 TAC 26.10). The purpose of the investigations was to identify all historic or prehistoric cultural resources located within the project area and to evaluate the significance and eligibility of identified resources for inclusion to the National Register of Historic Places (NRHP) or for designation as a State Antiquities Landmark (SAL). All work was done in accordance with the archaeological survey standards and guidelines as developed by the Council of Texas Archaeologists (CTA) and adopted by the Texas Historical Commission (THC). The investigations included a cultural resources background literature and records review and an intensive survey with mechanical trenching, followed by data recovery mitigation. Fieldwork for the initial survey took place between October 9, and November 12, 2015. The entirety of the project area was subject to visual inspection supplemented by systematically placed shovel tests in order to evaluate the impact of the proposed project on cultural resources. A second phase of survey with backhoe trenching followed on November 11 and 12, 2015. Archaeologists excavated a total of 28 shovel tests and 6 backhoe trenches, exceeding the minimum CTA/THC archaeological survey standards, which require a ratio of 1 shovel test per 2 acres for a 37‐acre (15‐ha) project area. Pape‐Dawson archaeologists encountered cultural material in 23 shovel tests and 5 trenches throughout the project area as part of their survey efforts. Site 41BX2131 was evaluated according to the criteria in 36 CFR 60.4 and 13 TAC 26.10, and determined to be potentially eligible for inclusion to the NRHP and for designation as an SAL. Based on the results of the survey and subsequent coordination with COSA. Archaeologist Kay Hindes, Pape‐Dawson conducted data recovery mitigation for 41BX2131 because it could not be avoided by development. Data recovery took place on January 6 to 8, 2016, and involved the excavation of three additional backhoe trenches and two 1‐by‐1‐meter, hand‐excavated units. One diagnostic projectile point, a Frio, was encountered in an excavation unit, and radiocarbon dated to 903±37 B.P. (D‐AMS 016005) (2‐sigma calibrated age estimate of A.D. 1035 to 1211, with a median probability of A.D. 1119). The generally accepted time range for Frio points is within the Transitional Archaic period at 200 B.C. to A.D. 600 or later (Turner and Hester 1999:122); in this case, more than 500 years later. One other radiocarbon date from the same unit, but 12 inches (30 centimeters [cm]) below the projectile point, was 1090±32 B.P. (D‐AMS 016006) (2‐sigma calibrated age estimate of A.D. 892 to 1015, with a median probability of A.D. 953), demonstrating that the preserved occupation at site 41BX2131 is limited to a 166‐ to 319‐year interval during the transition between the Transitional Archaic and Late Prehistoric periods. No pottery or arrow points typical of the Late Prehistoric period were encountered at site 41BX2131; however, the radiocarbon results situate the site within the early portion of the Late Prehistoric period. The many tested cobbles and large flakes present on the surface indicate that initial reduction took place here. Several preforms and bifaces noted on the surface, and the small size of many tertiary flakes from the data recovery also suggest more detailed work occurred. The actual borders of the site were not discovered, as they extend beyond the project area. The site has likely been destroyed by the surrounding urban development and associated infrastructure construction. Disturbances within the project area include vehicle trails, a sewage line, artifacts taken from the surface by prior owners, and erosion near the drainages. Project records and photographs will be curated at the Center for Archaeological Studies (CAS) at Texas State University in San Marcos, while artifacts will be returned to the landowner. Based on the results of the investigations, intact archaeological deposits that maximally span than about 300 years of occupation were documented at the site, including faunal bone and charcoal in the assemblage. Pape‐ Dawson archaeologists recommend that site 41BX2131 is eligible for inclusion to the NRHP and for designation as an SAL. No further work is recommended, as site 41BX2131 was mitigated through detailed hand‐excavations. If human remains are encountered during construction, Pape‐Dawson recommends that all work in the immediate area should cease and the appropriate agencies be contacted for guidance

    On method, theory, and the classification of complex disorders

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72867/1/j.1360-0443.1997.tb02886.x.pd

    Impact of the human footprint on anthropogenic mortality of North American reptiles

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    Human activities frequently result in reptile mortality, but how direct anthropogenic mortality compares to natural morality has not been thoroughly investigated. There has also been a limited examination of how anthropogenic reptile mortality changes as a function of the human footprint. We conducted a synthesis of causespecific North American reptile mortality studies based on telemetry, documenting 550 mortalities of known cause among 2461 monitored individuals in 57 studies. Overall 78% of mortality was the result of direct natural causes, whereas 22% was directly caused by humans. The single largest source of mortality was predation, accounting for 62% of mortality overall. Anthropogenic mortality did not increase with the human footprint or with species body mass, though predation mortality increased with decreasing human footprint. The relatively low amount of anthropogenic mortality compared to other taxa suggests that reptiles may be more impacted by indirect than direct anthropogenic mortality. As a result, mitigating these indirect impacts, which include habitat loss and introduction of invasive species, is essential for conservation of North American reptiles

    Cause‐specific mortality of the world’s terrestrial vertebrates

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    Aim: Vertebrates are declining worldwide, yet a comprehensive examination of the sources of mortality is lacking. We conducted a global synthesis of terrestrial vertebrate cause‐specific mortality to compare the sources of mortality across taxa and determine predictors of susceptibility to these sources of mortality. Location: Worldwide. Time period: 1970–2018. Major taxa studied: Mammals, birds, reptiles and amphibians. Methods: We searched for studies that used telemetry to determine the cause of death of terrestrial vertebrates. We determined whether each mortality was caused by anthropogenic or natural sources and further classified mortalities within these two categories (e.g. harvest, vehicle collision and predation). For each study, we determined the diet and average adult body mass of the species and whether the study site permitted hunting. Mortalities were separated into juvenile or adult age classes. We used linear mixed effects models to predict the percentage of mortality from each source and the overall magnitude of mortality based on these variables. Results: We documented 42,755 mortalities of known cause from 120,657 individuals representing 305 vertebrate species in 1,114 studies. Overall, 28% of mortalities were directly caused by humans and 72% from natural sources. Predation (55%) and legal harvest (17%) were the leading sources of mortality. Main conclusions: Humans were directly responsible for more than one‐quarter of global terrestrial vertebrate mortality. Larger birds and mammals were harvested more often and suffered increased anthropogenic mortality. Anthropogenic mortality of mammals and birds outside areas that prohibited hunting was higher than within areas where hunting was prohibited. Mammals experienced shifts from predominately natural to anthropogenic mortality as they matured. Humans are a major contributor to terrestrial vertebrate mortality, potentially impacting evolutionary processes and ecosystem functioning
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