Multi-object spectroscopy of the field surrounding PKS 2126-158: Discovery of a z=0.66 galaxy group

The high-redshift radio-loud quasar PKS 2126-158 is found to have a large number of red galaxies in close apparent proximity. We use the Gemini Multi-Object Spectrograph (GMOS) on Gemini South to obtain optical spectra for a large fraction of these sources. We show that there is a group of galaxies at $z\sim0.66$, coincident with a metal-line absorption system seen in the quasar's optical spectrum. The multiplexing capabilities of GMOS also allow us to measure redshifts of many foreground galaxies in the field surrounding the quasar. The galaxy group has five confirmed members, and a further four fainter galaxies are possibly associated. All confirmed members exhibit early-type galaxy spectra, a rare situation for a Mg II absorbing system. We discuss the relationship of this group to the absorbing gas, and the possibility of gravitational lensing of the quasar due to the intervening galaxies.Comment: Monthly Notices of the Royal Astronomical Society, in press. 10 pages, 8 figure

Why concert promoters matter

Forming a companion piece to Frith’s 2007 article on why live music matters, this paper argues that there is a need to refine accounts of the music industries to reflect live music’s growing dominance. It does so by focusing on the rock/pop concert promoter and posits that in contrast to traditional definitions, the role of the promoter is astonishingly flexible and adaptable. The authors argue that the promoter necessarily ‘wears many hats’ and offer three promotional models to understand the work that promoters do. To illustrate this and to understand the development of live music promotion in the UK from 1955 onwards, the article compares and contrasts historical research with contemporary ethnography

Single-pass baling productivity and grain logistics analysis

Corn stover harvest in Iowa was studied using a single-pass combine and baler configuration over the last three years. The combine experienced a productivity loss from pulling a baler through the field of 6-10% depending on field conditions and speed. The additional biomass harvested by the combine lowered productivity depending upon the harvest rate and yield of the biomass. At the 1.4 ton rate in 2011 fall harvest the average maximum productivity loss was 25-30%. The loss was experienced in experiments without factoring in grain logistics. A model was developed to look at the field logistics of the grain cart to and from a single-pass combine when unloading on the go. The model showed that only a 16% loss in actual productivity when compared to a conventional combine which unloaded on the go as well

Corn Stover Densification Methods and their Large-Scale Logistical Impacts—Preliminary Analysis

The bulk density of corn stover poses a major obstruction to its large scale acceptance as a biomass feedstock. The loose bulk density of corn stover is low enough to create large inefficiencies during the harvest, transport, and storage phases of production. Overall production costs of stover could be reduced if a densification method were developed that provided adequate bulk density at a low specific energy during the harvest phase of production. So far, stover densification has been accomplished either by baling, grinding, or briquetting processes. Baling faces a logistical challenge with the handling cost of an individual bale, grinding systems don’t achieve high enough bulk densities alone, and briquetting systems generally require stover preprocessing (grinding), and the addition of heat energy. All of these factors for each system drive up the unit cost of corn stover production

Investigation of Process Variables in the Densification of Corn Stover Briquettes

The bulk density of raw corn stover is a major limitation to its large-scale viability as a biomass feedstock. Raw corn stover has a bulk density of 50 kg/m3, which creates significant transportation costs and limits the optimization of transport logistics. Producing a densified corn stover product during harvest would reduce harvest and transportation costs, resulting in viable pathways for the use of corn stover as a biomass feedstock. This research investigated the effect of different process variables (compression pressure, moisture content, particle size, and material composition) on a densification method that produces briquettes from raw corn stover. A customized bench-scale densification system was designed to evaluate different corn stover inputs. Quality briquette production was possible using non-reduced particle sizes and low compression pressures achievable in a continuous in-field production system. At optimized bench settings, corn stover was densified to a dry bulk density of 190 kg/m3. Corn stover with a moisture content above 25%wb was not suitable for this method of bulk densification, and greater cob content had a positive effect on product quality

Production Scale Single-pass Corn Stover Large Square Baling Systems

A single-pass combine baler was operated in Central Iowa for the harvest of 2012 in a production scale setting. The combine’s performance was monitored with a telemetry data logger. The combine was able to harvest 2227 bushels (62.4 tons) of grain per hour on average and 18.8 tons of stover per hour on average. A complete quality analysis system was evaluated for the single-pass combine through the harvest of 2012. On board baler scales were tested showing a less than 1% difference in average weight between calibrated platform scales and the baler scales. Also, a microwave moisture meter was evaluated on a separate baler which showed between the 10% and 29% moisture level an R2 value of 87%

Understanding management practices for biomass harvest equipment for commercial scale operation

As second generation biofuels approach commercial scale production, a large fleet of harvesting equipment is required to meet feedstock demand. In the Midwest United States, agricultural residue, such as corn stover, has been identified as a readily available feedstock. Multi-pass corn stover harvest requires the in-field operations of shredding, baling, and stacking. Proper management practices are required to keep machines running at maximum efficiency in order to reduce cost and harvest enough material to meet processing demand. This need for management becomes increasing important as production levels reach commercial scale levels. This study looked at management practices of several individual harvest crews across an entire harvest season. Data was collected from multiple machines, including balers, shredders, and stackers during the 2013 and 2014 fall harvests. The controller area network (CAN) bus system was utilized to record machine data that was linked to specific GPS coordinates within a given field. The information was then analyzed to identify controllable metrics, such as machine productivity, daily bale production, and bale density. Recognizing these controllable metrics will improve overall logistics as production reaches full scale and reduce overall costs. A techno-economic analysis was executed to quantify cost as performance and quality changed

Productivity and Logistical Analysis of Single-Pass Stover Collection Harvest Systems

A modified biomass combine was used in field experiments focused on measuring the productivity of single-pass bulk harvest and single-pass bale harvest systems. These harvesting machines were outfitted with ISOBUS data loggers to track overall in-field performance data. Testing of machine productivity was conducted at .7 ton/ac (1.6 Mg/ha), 1.5 ton/ac (3.4 Mg/ha), and 2.4 ton/ac (5.4 Mg/ha) for each system. The combine was also tested in a conventional configuration to provide baseline productivity data. Testing revealed significant impacts of the harvesting system on overall machine productivity and highlight the need for additional machine development to support the collection and harvest of biomass residues and grain

Technical Note: Durability Analysis of Large Corn Stover Briquettes

Densification of agricultural residues is a key step in a cost-effective, large-scale, biomass feedstock supply system. Lab-scale densification systems exist which can produce large-scale densified corn stover briquettes that measure between 220 and 420 mm in length and with an average bulk density of 190 kg/m3 (dry particle density of 460 kg/m3). MOG (material other than grain ) and pure cob briquettes produced similar lengths and dry particle densities of 424 kg/m3 and 421 kg/m3, respectively. Durability testing, utilizing a modified form of ASABE S269.4 (ASABE Standards, 2007) was conducted to determine the overall product quality associated with these densified briquettes. This publication describes experiments which quantified the durability or briquettes produced with different material types (corn stover, MOG, the chaff from a conventional corn harvest, and pure cobs) and material particle sizes (produced from a combine chopper, MOG, and a hammer mill with a 19-mm screen opening size). The durability rating varied with each of the main effect test parameters and produced a maximum 46% durability rating using pure cobs directly from a combine without additional size reduction. The durability rating was quite low for corn stover and MOG briquettes, and it was improved for pure cob briquettes. Biomass preprocessing in a hammermill significantly reduced durability due to a lack of fiber interaction throughout the large briquette