Flame Speed and Spark Intensity

This report describes a series of experiments undertaken to determine whether or not the electrical characteristics of the igniting spark have any effect on the rapidity of flame spread in the explosive gas mixtures which it ignites. The results show very clearly that no such effect exists. The flame velocity in carbon-monoxide oxygen, acetylene oxygen, and gasoline-air mixtures was found to be unaffected by changes in spark intensity from sparks which were barely able to ignite the mixture up to intense condenser discharge sparks having fifty time this energy. (author

Electrical characteristics of spark generators for automotive ignition

This paper reports the results of an extensive program of measurements on 11 ignition systems differing widely in type. The results serve primarily to give representative data on the electric and magnetic constants of such systems, and on the secondary voltage produced by them under various conditions of speed, timing, shunting resistance, etc. They also serve to confirm certain of the theoretical formulas which have been proposed to connect the performance of such systems with their electrical constants, and to indicate the extent to which certain simplified model circuits duplicate the performance of the actual apparatus

Improving the precision of dynamic forest parameter estimates using Landsat

The use of satellite-derived classification maps to improve post-stratified forest parameter estimates is well established.When reducing the variance of post-stratification estimates for forest change parameters such as forest growth, it is logical to use a change-related strata map. At the stand level, a time series of Landsat images is ideally suited for producing such a map. In this study, we generate strata maps based on trajectories of Landsat Thematic Mapper-based normalized difference vegetation index values, with a focus on post-disturbance recovery and recent measurements. These trajectories, from1985 to 2010, are converted to harmonic regression coefficient estimates and classified according to a hierarchical clustering algorithm from a training sample. The resulting strata maps are then used in conjunction with measured plots to estimate forest status and change parameters in an Alabama, USA study area. These estimates and the variance of the estimates are then used to calculate the estimated relative efficiencies of the post-stratified estimates. Estimated relative efficiencies around or above 1.2 were observed for total growth, total mortality, and total removals, with different strata maps being more effective for each. Possible avenues for improvement of the approach include the following: (1) enlarging the study area and (2) using the Landsat images closest to the time of measurement for each plot. Multitemporal satellite-derived strata maps show promise for improving the precision of change parameter estimates

Improving the precision of dynamic forest parameter estimates using Landsat

The use of satellite-derived classification maps to improve post-stratified forest parameter estimates is well established.When reducing the variance of post-stratification estimates for forest change parameters such as forest growth, it is logical to use a change-related strata map. At the stand level, a time series of Landsat images is ideally suited for producing such a map. In this study, we generate strata maps based on trajectories of Landsat Thematic Mapper-based normalized difference vegetation index values, with a focus on post-disturbance recovery and recent measurements. These trajectories, from1985 to 2010, are converted to harmonic regression coefficient estimates and classified according to a hierarchical clustering algorithm from a training sample. The resulting strata maps are then used in conjunction with measured plots to estimate forest status and change parameters in an Alabama, USA study area. These estimates and the variance of the estimates are then used to calculate the estimated relative efficiencies of the post-stratified estimates. Estimated relative efficiencies around or above 1.2 were observed for total growth, total mortality, and total removals, with different strata maps being more effective for each. Possible avenues for improvement of the approach include the following: (1) enlarging the study area and (2) using the Landsat images closest to the time of measurement for each plot. Multitemporal satellite-derived strata maps show promise for improving the precision of change parameter estimates

Measuring the Effects of Narrative and Analytical Messages in Video Production

Communication practitioners in the agriculture industry have the challenge of identifying the best way to educate consumers, and they have experienced challenges in consumer engagement. Additionally, food safety issues have continued to rise with a trend of recalls and foodborne illnesses. While the rhetoric in the agriculture industry is pointing to the need for agricultural issues to be addressed from an agriculturist sharing their stories and perspectives, there is limited research on the impact of personal narratives on attitude change and message elaboration. The purpose of this study was to determine the effects of narrative and analytical practices on elaboration, attitude, and transportation in order to better communicate about food safety practices. The researcher used Elaboration Likelihood Model, cognitive theory of multimedia learning, and narrative transportation as the theoretical framework. To test the objectives, a two (type of media: narrative and analytical) x three (length of media: short, medium and long) between-subjects factorial design was implemented. Respondents were randomly assigned to one of the experimental treatments. The respondents in this study were comprised of a non-probability sample of 712 [State] residents over the age of 18 years. Usable responses were received from 507 (71%) respondents. This study found that all videos resulted in positive attitudes toward the information and practices on the farm. Further research into narrative transportation, length of videos, and type of videos may provide an efficient approach to developing communication that narrows the educational disconnect between consumers, producers, and the production practices on the farm

To Post or Not to Post? Factors Influencing State FFA Officers’ Social Media Behaviors

The demand for agriculture, food, and natural resource (AFNR) messages to be conveyed via channels of social media provides a natural inclination to seek out digital natives, such as state FFA officers, to fill the present gap of agriculturalists in online environments. The purpose of this study was to examine the factors that influence state FFA officers’ behaviors of communicating about AFNR issues on social networking sites. The theoretical framework that guided this study of communication behaviors was the theory of planned behavior. A census of the accessible population of 276 state officers was attempted, and 97 usable responses were received (35.1%). The findings reinforced the use of the theory of planned behavior to understand, predict, and change AFNR social media behaviors. The significance of subjective norms suggested that online AFNR communication is mainly under subjective control for state FFA officers. To increase online engagement of state FFA officers, it is recommended that behavioral change efforts target normative beliefs and that clear behavioral expectations are expressed. Further research is recommended to determine if the significance of subjective norms as a predictor of intent is unique to technological and social media behaviors or applicable to a broader context. Additional research with other populations of young agriculturalists is also recommended

Analyzing Media Coverage of Agricultural Health and Safety Issues

Farming, by the very nature of the occupation, is riddled with uncertainty. The risks associated with the agriculture industry are just as diverse as the industry itself. For all risks, one challenge is the development and dissemination of safety communication materials tailored for diverse audiences. Valkenburg, Semetko, and Vreese (1999) examined common frames used in news media. Their analysis pointed to four commonly used news frames: conflict, human interest, responsibility and economic consequences. The purpose of this study was to describe the agricultural and health safety issues discussed in Florida news media during the year 2016, discussing the prominence of the frames outlined by Valkenburg et al. (1999). In this study, the most prominent frame was the human interest frame, followed by responsibility, economic consequences, and conflict. Frames carry a great deal of weight in shaping individuals’ opinions, attitudes, and actions towards agriculturally based messages; therefore it is essential for agricultural communicators to understand the framing of agricultural health and safety issues. Acknowledging the frames used in the reporting of agricultural issues allows agricultural communicators to enter into informed interactions with media outlets and better prepare the resources they provide to them. These framing analyses also provide agricultural communicators with a solid foundation on which to best position and frame their messaging on behalf of the industry. Further research is recommended to examine frames from an audience perspective and to investigate the impact of human interest frames in the presentation of agricultural news articles

Protein evolution by hypermutation and selection in the B cell line DT40

Genome-wide mutations and selection within a population are the basis of natural evolution. A similar process occurs during antibody affinity maturation when immunoglobulin genes are hypermutated and only those B cells which express antibodies of improved antigen-binding specificity are expanded. Protein evolution might be simulated in cell culture, if transgene-specific hypermutation can be combined with the selection of cells carrying beneficial mutations. Here, we describe the optimization of a GFP transgene in the B cell line DT40 by hypermutation and iterative fluorescence activated cell sorting. Artificial evolution in DT40 offers unique advantages and may be easily adapted to other transgenes, if the selection for desirable mutations is feasible

Observations of Kuroshio flow variations in the East China Sea

Kuroshio velocity structure and transport in the East China Sea (ECS) were investigated as part of a 23‐month study using inverted echo sounders and acoustic Doppler current profilers (ADCPs) along the regularly sampled PN‐line. Flow toward the northeast is concentrated near the continental shelf with the mean surface velocity maximum located 30 km offshore from the shelf break (taken as the 170 m isobath). There are two regions of southwestward flow: a deep countercurrent over the continental slope beneath the Kuroshio axis and a recirculation offshore which extends throughout the whole water column. There is a bimodal distribution to the depth of maximum velocity with occurrence peaks at the surface and 210 dbar. When the maximum velocity is located within the top 80 m of the water column, it ranges between 0.36 m/s and 2.02 m/s; when the maximum velocity is deeper than 80 m, it ranges between 0.31 m/s and 1.11 m/s. The 13‐month mean net absolute transport of the Kuroshio in the ECS is 18.5 ± 0.8 Sv (standard deviation, σ = 4.0 Sv). The mean positive and negative portions of this net flow are 24.0 ± 0.9 Sv and −5.4 ± 0.3 Sv, respectively