bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying Nitrogen Requirement for Creeping Bentgrass Putting‐Green Cultivars
Authors: Baldwin C. M. , Brede A. D.
Published: August 2012

Nitrogen is perhaps the most important nutrient for turfgrasses because it improves color, density, and recuperative ability when applied at adequate rates. Although numerous unique traits, such as dark genetic color and improved stress tolerance have been identified, there is a lack of published data comparing creeping bentgrass cultivar N use. Therefore, a field study was initiated in 2009 and 2010 to identify creeping bentgrass (Agrostis stolonifera L.) putting‐green cultivars that required the least amount of N to maintain acceptable color while maintaining desirable agronomic traits and good overall playability. Eighteen creeping bentgrass cultivars were planted on 2 July 2006 and maintained at a 3.2‐mm mowing height. Nitrogen, liquid urea, was applied at 49, 147, or 294 kg ha−1 yr−1. Nitrogen applications were applied every 2 wk from April to October. Data collection included turfgrass color, relative chlorophyll index (RCI), clipping yield, lateral regrowth, ball‐roll distance, and thatch accumulation. Increasing N rates resulted in higher RCI, more top growth, faster lateral regrowth, and shorter ball‐roll distances. Regarding thatch accumulation, no significant differences were detected between cultivars. Overall, the creeping bentgrass cultivars that maintained acceptable color with the least amount of N input included ‘007’, ‘Authority’, ‘Penn A‐4’, ‘Shark’, and ‘T‐1’. These cultivars also maintained desirable agronomic traits, such as high RCI, reduced clipping yield, increased lateral regrowth, and adequate ball‐roll distance. This research indicates creeping bentgrass cultivar is an important selection criterion if a reduction in N use is a relevant consideration.
Waste Streams from Methane Digesters: Exporting Nutrients through Turfgrass and Forage Production Systems
Authors: Schnell Ronnie W. , Vietor Donald M. , Provin Tony L. , Munster Clyde L.
Published: August 2012

Similar to manure, residual manure solids (MS) from methane digesters require cropping systems and management practices that optimize nutrient export to prevent large increases in soil P levels. The objectives were to compare forage and turfgrass sod production systems with respect to effects of MS management practices on soil properties and crop productivity and to compare mass balance of N and P on field scale. A 2‐yr field experiment was conducted on a fine sandy loam soil receiving MS to compare nutrient imports, forms in soil, and export by Tifton 85 bermudagrass (Cynodon spp.) grown for forage and Tifway bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis (Burtt‐Davy)] grown for turfgrass sod. Five soil treatments for each crop included MS with and without Alum topdressed (250 kg total phosphorus [TP] ha−1) annually or a single application of MS (500 kg TP ha−1) incorporated compared to soil without MS. One harvest of Tifway sod removed 2.7 times more total nitrogen (TN) and 2.8 times more TP than three harvests of Tifton 85 forage biomass during the first year of production. Greater biomass production and nutrient uptake by Tifton 85 forage during the second production season reduced the difference in nutrient export between Tifton 85 and Tifway sod. Turfgrass sod production systems can be used by producers to increase export of MS applied nutrients compared to forage production and enable waste streams from methane digesters to be recycled.
In Vitro Evaluation of Coatings to Control Ammonia Volatilization from Surface‐Applied Urea
Authors: Frame W. Hunter , Alley M. M , Whitehurst G. B. , Whitehurst B. M. , Campbell R.
Published: August 2012

Ammonia (NH3) volatilization from surface‐applied N fertilizers containing urea can be substantial if environmental conditions are favorable. Physically coating urea with sulfate salts and urease inhibitor may reduce NH3 volatilization and supply plant available S. The objectives of this study were to quantify in vitro N loss from surface‐applied urea; and measure the rate and total N volatilization loss from urea coated with calcium sulfate, potassium sulfate, alone and in combination with the urease inhibitor, N‐(n‐butyl) thiophosphoric triamide (NBPT). Six trials, lasting 14 d, were conducted using a laboratory system at 26°C, 1.00 L min−1air flow, 44.6 mg N kg−1air‐dried soil, and 100 mL of 0.02 M phosphoric acid to recover volatilized NH3. Cumulative NH3 loss ranged from 33.9 to 37.2% of the applied N in all trials. Initial NH3 volatilization losses were delayed by calcium and potassium sulfate coatings alone. The inhibitor NBPT reduced cumulative NH3 losses to 17.9 to 24.7% of applied N and delayed NH3 volatilization for 96 h after N application when applied at the 0.08% w/w application rate in trials I to IV. In trials V and VI, applying NBPT at 0.02% w/w reduced cumulative NH3 volatilization from 35.6 and 35.1% to 25.4 and 24.1%, respectively. In both trials, no difference in cumulative NH3 loss was observed when NBPT rates exceeded 0.04%. The inhibitor NBPT had the greatest influence on NH3 volatilization losses in these studies, though the K2SO4 coated urea also reduced NH3 volatilization and supplies a small amount of S for crop growth.
Sowing Method Effects on Clover Establishment into Permanent Pasture
Authors: Schlueter David , Tracy Benjamin
Published: August 2012

A study was conducted from 2009 to 2011 near Blacksburg, VA, to gain a better understanding of how sowing method affected establishment and persistence of clover in permanent cool‐season grass pastures. Four 1.1‐ha pastures were split in half and assigned a broadcasted or no‐till drilled sowing treatment. Pasture treatments were sown with an equal proportion of red (Trifolium pratense L.) and white clover (Trifolium repens L.) each at 4.4 kg ha−1 in February 2009. Residual grass biomass on pastures was measured at sowing, and clover seedling density was counted 2 mo later. Grass, white clover, red clover, and weed biomass were measured four times during each growing season. Broadcast treatments had 56% more clover seedlings than drilled treatments 2 mo after sowing, but this difference was not significant (P = 0.1087). No difference (P > 0.10) for clover biomass was observed between sowing treatments in any year, yet clover establishment was considered successful (>25% of pasture composition). In the drilled treatments, clover seedling density was negatively affected by the amount of residual grass biomass present during sowing (P = 0.0196). In the broadcasted treatment, a negative quadratic relationship between clover seedling density and residual grass biomass at sowing was found (P = 0.0516). For successful establishment of clovers into permanent pastures, these data imply that removing residual grass biomass before sowing was more important than seeding method.
Tradeoffs in Performance of Native Warm‐Season Grass Cultivars and Locally Harvested Seed Managed for Wildlife Habitat or Livestock Production
Authors: Chamberlain S. K. , Paine L. K. , Harrison J. L. , Jackson R. D.
Published: August 2012

Native warm‐season grasses have potential to increase the ecosystem services associated with grazing lands and to provide a source of forage for livestock. In the upper Midwest, minimal region specific information is available to grass‐based farmers on how to manage native pastures for long‐term productivity and persistence. Wildlife biologists suggest delaying defoliations until mid‐summer to preserve grassland bird habitat, yet production‐based management recommendations warn against late season defoliations. Moreover, the source of seed to use for pasture establishment, cultivar or locally harvested seed (LHS), is unclear. We initiated an on‐farm experiment to evaluate the effects of two rotational grazing schedules, June to July or July to September, for differences in vegetation cover, vigor, yield, and nutritive value of paddocks seeded with native warm‐season grass cultivars or LHS. After 2 yr, native grass cover was similar across all treatments. Vigor, as measured by spring etiolated growth, was sustained under grazing and across seed sources for the dominant native grasses big bluestem (Andropogon gerardiiVitman) and Indiangrass [Sorghastrum nutans(L.) Nash]. Total yield was greatest when grazing was deferred until July, but this resulted in decreased nutritive value for both seed sources. These results indicate that native warm‐season grasses have potential to persist under rotational grazing in upper Midwest pasture systems and that pasture performance is controlled by the timing of the first grazing cycle. The lack of a consistent seed source effect suggests that the LHS and cultivars used in the study are suitable for pasture use in the region.
Yield, Pests, and Water Use of Durum and Selected Crucifer Oilseeds in Two‐Year Rotations
Authors: Lenssen A. W. , Iversen W. M. , Sainju U. M. , Caesar-TonThat T. C. , Blodgett S. L. , Allen B. L. , Evans R. G.
Published: August 2012

Cool‐season oilseed crops are potential feedstock for biofuel production, but few studies have compared oilseed‐durum (Triticum durum Desf.) rotations on yield, quality, water use, and pests associated with crops. We conducted an experiment under dryland conditions during 2007 to 2010 near Culbertson, MT, comparing crop productivity, water balance, and key weed and arthropod pests of 2‐yr oilseed‐durum rotations under zero tillage. Rotations included durum with three Brassicaceae sp., camelina [Camelina sativa (L.) Crantz], crambe (Crambe abyssinica Hochst. ex R.E. Fries), and canola‐quality Brassica juncea L., and fallow. Over 4 yr, B. juncea had the highest seed and oil yields of crucifer entries. Water use was similar among oilseed crops, averaging 286 mm. Water use was similar for durum following oilseeds, averaging 282 mm, 72 mm less than for durum following fallow. Durum following fallow averaged 775 kg ha−1 greater grain yield than durum following oilseeds due to higher water availability and use. Camelina had greater weed biomass at harvest and lower densities of Plutella xylostella L. than other oilseeds. Durum in rotation with crambe had higher weed density and biomass at harvest than durum following B. juncea or fallow. Brassica juncea generally performed better than crambe or camelina, but each oilseed crop had several positive attributes. Oilseed‐durum rotations can be used for biofuel feedstock and grain production, but long‐term sustainability of 2‐yr rotations on crop yields and pest management requires further study.
Tillage Effects on Yield and Nitrogen Fixation of Legumes in Mediterranean Conditions
Authors: Ruisi Paolo , Giambalvo Dario , Di Miceli Giuseppe , Frenda Alfonso Salvatore , Saia Sergio , Amato Gaetano
Published: August 2012

The no‐tillage (NT) technique represents a valuable alternative to conventional tillage (CT) for many crops, but little research has evaluated the effects of its use on the performance of grain legumes, particularly in Mediterranean regions. The present study assessed the effects of NT compared with CT on the grain yield and N2 fixation of chickpea (Cicer arietinum L.), faba bean (Vicia faba L. variety minor), pea (Pisum sativum L.), and lentil (Lens culinaris Medik.). The experiment was performed under rainfed conditions during four growing seasons. Nitrogen fixation was estimated using the 15N isotope dilution technique. The response of the four species to the tillage system varied significantly by year. The grain yield was significantly higher under NT than under CT only for pea and chickpea, but the differences between the two tillage techniques were consistent only when rainfall was very scarce. The percentage of N fixed differed by species in the order faba bean > chickpea > pea > lentil. The effects of tillage on the N2 fixation process varied significantly by species and year. Nitrogen balance was positive for faba bean and lentil and negative for chickpea and pea, with no differences by tillage. The results indicate that in cereal‐dominated Mediterranean agro‐ecosystems NT can be a valuable option for producing grain legumes, as it can improve productivity, particularly under conditions of deficient soil moisture.
Rooting in a Creeping Bentgrass Putting Green in Response to Spring and Summer Coring
Authors: Fu Jinmin , Dernoeden Peter H.
Published: August 2012

Understanding root growth response of creeping bentgrass (Agrostis stolonifera L.) to coring will help golf course superintendents maintain high quality putting green turf. The objective of this field study was to examine the effects of coring on summer rooting in young creeping bentgrass grown on a sand‐based root zone and maintained as a putting green. The study was initiated on 7‐mo‐old ‘Providence' creeping bentgrass in 2006 and compared spring (SP) only coring, spring plus three summer (SU) corings (SP + SU) and a noncored control through 2007. The minirhizotron imagining technique was used to measure total root count (TRC) and total root length (TRL) from late spring to late summer. The percentage of the TRC in the surface 0‐ to 6‐cm root zone depth averaged over measurement dates was 48 to 53% and 33 to 44% among all treatments in 2006 and 2007, respectively. Greater TRC were observed in 2006 with 28, 51, and 50% lower TRC's found in SP + SU, SP only, and noncored plots in 2007, respectively. Spring + SU coring generally reduced TRC and TRL at various root zone depths and dates during the first year of establishment. In 2007, greater TRC and TRL were observed throughout the 0‐ to 24‐cm root zone in SP + SU cored compared to SP only and noncored plots. Thus, SP + SU coring in the second study year promoted creeping bentgrass root growth and/or longevity, but coring during the first summer of establishment reduced rooting.
Effect of Cultivar, Irrigation, and Soil Calcium on Runner Peanut Response to Gypsum
Authors: Howe J. A. , Florence R. J. , Harris G. , van Santen E. , Beasley J. P. , Bostick J. P. , Balkcom K. B.
Published: August 2012

Calcium is often limiting to peanut (Arachis hypogaea L.) yield, grade, and germination in the southeastern United States. The response of large‐seeded (Georgia‐06G) and small‐seeded (Georgia Green) runner peanuts to gypsum applications was evaluated in 14 tests in southern Alabama and Georgia. Experiments were conducted in a randomized complete block design with four replications of gypsum applications as main treatments (0, 560, 1120, and 1680 kg ha−1) in soils with a range of soil Ca (178–498 mg kg−1) in both irrigated and non‐irrigated tests. Increases in yield, grade, seed Ca, and germination were significant with increased gypsum application for non‐irrigated tests when data were combined. In the non‐irrigated tests, yield increases ranged from 500 to 1000 kg ha−1 and grade indicated by sound mature kernels (SMK) increased 3.4 to 5%. Critical pegging zone soil Ca values of 150 and 250 mg kg−1 were evaluated and found appropriate for irrigated and non‐irrigated peanuts, respectively. Georgia‐06G had lower seed Ca concentrations and slightly lower germination than Georgia Green. More than 95% germination of Georgia‐06G and Georgia Green was observed when seed Ca concentrations were >600 mg kg−1. Analysis of Ca concentrations in nearly mature seeds pre‐harvest may provide an indication of seed germination quality as seed Ca concentration increased at approximately the same rate as seed size from immature white to mature black peanut maturity classes using the hull‐scrape method.
Dialysis Search Filters for PubMed, Ovid MEDLINE, and Embase Databases
Authors: Iansavichus Arthur V. , Haynes R. Brian , Lee Christopher W.C. , Wilczynski Nancy L. , McKibbon Ann , Shariff Salimah Z. , Blake Peter G. , Lindsay Robert M. , Garg Amit X.
Published: August 2012

Background and objectives

Physicians frequently search bibliographic databases, such as MEDLINE via PubMed, for best evidence for patient care. The objective of this study was to develop and test search filters to help physicians efficiently retrieve literature related to dialysis (hemodialysis or peritoneal dialysis) from all other articles indexed in PubMed, Ovid MEDLINE, and Embase.

Design, setting, participants, & measurements

A diagnostic test assessment framework was used to develop and test robust dialysis filters. The reference standard was a manual review of the full texts of 22,992 articles from 39 journals to determine whether each article contained dialysis information. Next, 1,623,728 unique search filters were developed, and their ability to retrieve relevant articles was evaluated.

Results

The high-performance dialysis filters consisted of up to 65 search terms in combination. These terms included the words “dialy” (truncated), “uremic,” “catheters,” and “renal transplant wait list.” These filters reached peak sensitivities of 98.6% and specificities of 98.5%. The filters’ performance remained robust in an independent validation subset of articles.

Conclusions

These empirically derived and validated high-performance search filters should enable physicians to effectively retrieve dialysis information from PubMed, Ovid MEDLINE, and Embase.
Parietal Epithelial Cell Activation Marker in Early Recurrence of FSGS in the Transplant
Authors: Fatima Huma , Moeller Marcus J. , Smeets Bart , Yang Hai-Chun , D’Agati Vivette D. , Alpers Charles E. , Fogo Agnes B.
Published: August 2012

Background and objectives

Podocyte loss is key in glomerulosclerosis. Activated parietal epithelial cells are proposed to contribute to pathogenesis of glomerulosclerosis and may serve as stem cells that can transition to podocytes. CD44 is a marker for activated parietal epithelial cells. This study investigated whether activated parietal epithelial cells are increased in early recurrent FSGS in transplant compared with minimal change disease.

Design, setting, participants, & measurements

CD44 staining in renal allograft biopsies from 12 patients with recurrent FSGS was performed and compared with native kidneys with minimal change disease or FSGS and normal control native and transplant kidneys without FSGS. CD44+ epithelial cells along Bowman’s capsule in the parietal epithelial cell location and over the glomerular tuft in the visceral epithelial cell location were assessed.

Results

Cases with early recurrent FSGS manifesting only foot process effacement showed significantly increased CD44+ visceral epithelial cells involving 29.0% versus 2.6% of glomeruli in minimal change disease and 0% in non-FSGS transplants. Parietal location CD44 positivity also was numerically increased in recurrent FSGS. In later transplant biopsies, glomeruli with segmental lesions had more CD44+ visceral epithelial cells than glomeruli without lesions.

Conclusions

Parietal epithelial cell activation marker is significantly increased in evolving FSGS versus minimal change disease, and this increase may distinguish early FSGS from minimal change disease. Whether parietal epithelial cell activation contributes to pathogenesis of sclerosis in idiopathic FSGS or is a regenerative/repair response to replace injured podocytes awaits additional study.
The Primary Care Perspective on Routine Urine Dipstick Screening to Identify Patients with Albuminuria
Authors: Samal Lipika , Linder Jeffrey A.
Published: August 2012

Proponents of routine urine dipstick screening to identify patients at risk for ESRD in the primary care setting have argued that urine dipsticks are inexpensive, low risk, acceptable to patients, and now, more accurate. Proponents believe that urine dipstick screening has the potential to improve outcomes for people with early disease and increase awareness of CKD. Most primary care physicians agree that populations who are at high risk for CKD should be tested and appropriately treated to decrease complications of ESRD. However, proponents of mass screening may not appreciate the challenges, limitations, and potential harms of screening. Urine dipstick testing does not meet all of the criteria for a good screening test. Screening the general population with urine dipsticks will generate many false positives—between 50% and 90% of positive tests—that will require follow-up, increase costs, and cause patient anxiety. Routine screening with urine dipsticks is not cost-effective on the order of $200,000 per quality-adjusted life year. Most importantly, there is little evidence that early identification of microalbuminuria in unselected patients influences outcomes of CKD. Without proof of effectiveness, overdiagnosis, a problem for even well established screening tests, is risked. Finally, no specialty society or preventive services group currently recommends general screening. Instead of screening, primary care physicians and nephrologists should work together to identify patients at high risk for ESRD and optimize management to improve outcomes for patients with CKD.
The Association of Albumin/Creatinine Ratio with Postoperative AKI in Children Undergoing Cardiac Surgery
Authors: Zappitelli Michael , Coca Steven G. , Garg Amit X. , Krawczeski Catherine D. , Thiessen Heather Philbrook , Sint Kyaw , Li Simon , Parikh Chirag R. , Devarajan Prasad
Published: August 2012

Background and objectives

This study determined if preoperative and postoperative urine albumin/creatinine ratios (ACRs) predict postoperative AKI in children undergoing cardiac surgery (CS).

Design, setting, participants, & measurements

This was a three-center, prospective study (2007–2009) of 294 children undergoing CS (n=145 aged <2 years). Urine ACR was measured preoperatively and 0–6 hours after intensive care unit arrival. AKI outcomes were based on the Acute Kidney Injury Network serum creatinine (SCr) criteria (stage 1 AKI, ≥50% or 0.3 mg/dl SCr rise from baseline; and stage 2 or worse AKI, ≥SCr doubling or dialysis). AKI was predicted using preoperative and postoperative ACRs and postoperative ACR performance was compared with other AKI biomarkers.

Results

Preoperative ACR did not predict AKI in younger or older children. In children aged <2 years, first postoperative ACR ≥908 mg/g (103 mg/mmol) predicted stage 2 AKI development (adjusted relative risk, 3.4; 95% confidence interval, 1.2–9.4). In children aged ≥2 years, postoperative ACR ≥169 mg/g (19.1 mg/mmol) predicted stage 1 AKI (adjusted relative risk, 2.1; 95% confidence interval, 1.1–4.1). In children aged ≥2 years, first postoperative ACR improved AKI prediction from other biomarker and clinical prediction models, estimated by net reclassification improvement (P≤0.03), but only when serum cystatin C was also included in the model.

Conclusions

Postoperative ACR is a readily available early diagnostic test for AKI after pediatric CS that performs similarly to other AKI biomarkers; however, its use is enhanced in children aged ≥2 years and in combination with serum cystatin C.
Market Reactions to Departures of Audit Committee Directors
Authors: Singhvi Meghna , Rama Dasaratha V. , Barua Abhijit
Published: August 2012

SYNOPSIS:

The composition and functioning of audit committees have come under increasing scrutiny from legislators and regulators in recent years. We examine the market reaction to 107 audit committee director departures that occur (without any concurrent appointment to the board or other contemporaneous news) during 2005 to 2008. We find that there is a significant negative market reaction to the departure of accounting experts, but not for the departures of other types of experts or non-expert directors. Considering a subsample of expert director departures, we find that the market reaction is significantly negative for the departure of short-tenured directors, but not for the departure of long-tenured directors.
Safe laser system design for production
Authors: Kestenbaum Ami , Coyle Richard J. , Solan Patrick P.
Published: August 2012

The majority of industrial lasers used in manufacturing are Class IV lasers. Engineering and administrative control measures appropriate to that class of lasers must be enforced to ensure their safe use in production environments, i.e. they should be designed into Class 1 laser systems. In addition, several other design characteristics unique to industrial applications are normally incorporated into these Class I systems, such as interlocked enclosures, process monitoring by means of closed circuit television (CCTV) or microscope optics, and optical fibers as well as conventional, fixed optics for laser beam delivery. The accessible emission for an integrated production laser system must be below the Accessible Emission Limit for a Class I laser. This paper addresses solutions to safety design issues through examples of production industrial laser systems. The appropriate administrative control programs that complement the engineering control measures are also discussed.
Taking advantage of laser properties to enhance demonstrations and student laboratories
Authors: Brill Michele L.
Published: August 2012

This paper reflects the proceedings of a workshop for local educators provided by Camden County College Laser Curriculum faculty which addressed the question: ‘How can the teacher take advantage of laser properties to improve or enhance demonstrations and student labs?’ Explored here are illustrative ways in which to utilize, for educational purposes, the three well-known characteristics of lasers: monochromaticity, directionality, and coherence. There is a faculty overlap between the Physics Department and the Laser Curriculum faculty at the college. The use of lasers in the classroom, then, has a two-fold purpose: first, to teach about lasers, and second, to teach with lasers. The first objective is accomplished largely in a new facility, the Laser Institute of Technology for Education and Research (LITER building), a free-standing building housing laser and fiber-optic programs. It features a wide selection of lasers and allows use of various tuning options of some of them for demonstrations and student labs connected with optics classes and other laser curriculum courses. The Physics Department provides the usual Class II or lower (for safety reasons) lasers to be used for demonstrations and student labs. Physics classes are at three levels: preparatory, college (algebra-based), and transfer (calculus-based). The lasers permit ground to be covered quickly and effectively at all levels. A current project at the transfer curriculum level will be described.
Electrical hazards associated with lasers
Authors: Varanelli Arthur G.
Published: August 2012

The range and degree of electrical hazards associated with lasers is generally greater than encountered with other forms of equipment in the industrial, commercial, or scientific sectors. In laser equipment the electrical energy conversion to ‘optical’ wavelength energy is achieved by many methods, each method having differing electrical safety hazard exposures. Laser output is described in terms of beam power, energy, wavelength, and spatial characteristics, enabling common points of comparison and beam hazard characterization. In contrast, the methods of electrical energy conversion have unique characteristics which are not generally appreciated. It is natural to expect this, as it is the laser beam that is the instrument of useful work, not the manner in which the beam is produced. The fact that certain energy conversion methods require electrical equipment having more in common with radar transmitters leaves open the problem of severe electrical hazards through unfamiliarity and inexperience. Many severe electric shock accidents with laser power-supply and pulse-forming equipment have occurred for these reasons. Several common electrical energy conversion systems and their general electrical safety requirements are discussed and connections to the requirements and expectations of current codes and regulations are explored. An understanding of the triad of equipment exposures, equipment environment, and the human element is developed to provide a greater appreciation of the necessity for recognition, evaluation, and control if electric shock accidents are to be avoided.
Hazardous emissions: characterization of CO2 laser material processing
Authors: Haferkamp H. , Goede M. , Engel K. , Wittbecker J.-S.
Published: August 2012

Parallel to the growth of laser technology is a high interest in safety in industrial surroundings. The characteristics of hazards resulting from laser processing are complex and highly interdependent. In addition, very little fundamental scientific research on this topic exists. The Laser Zentrum Hannover e.V. (LZH) is working on a research project subsidized by the BMFT (German Federal Ministry for Research and Technology) concerning the characterization and reduction of hazardous emissions resulting from laser material processing. The goal of this project is to identify emission products and to quantify hazardous emission components from laser cutting and welding of processed materials. The results should serve as a basis for exhaust and filter technologies. The final aim is to develop an exhaust and filtration system that is especially adapted to laser material processing. This report deals with the characterization of emissions resulting from CO2 laser cutting of thermoplastics.
A study of polarization-maintaining fiber characteristics with applications to force and displacement sensing
Authors: Yupapin P. V. P. , Weir K. , Grattan K. T. V. , Palmer A. W.
Published: August 2012

An experimental investigation of three different types of highly birefringent fiber sensor element configured as a force and a displacement sensor is described. From the coupling of power between the two eigenmodes, the magnitude of the force and the position of the coupling point can then be determined using ‘white-light interferometric’ techniques.
Understanding laser hazard evaluation
Authors: Marshall Wesley J.
Published: August 2012

The current 1993 version of the ANSI Z136.1 standard for the safe use of lasers provides maximum permissible exposures which more closely match available biological injury data. Interpreting the standard can be more difficult at times than with previous versions. By keeping the biological injury mechanism in mind, the reasoning behind the multitude of rules contained in the standard are more understandable.
Fiber optic equipment to supplement today's laser electro-optic laboratories and global communication highway
Authors: Cellucci Thomas A.
Published: August 2012

As the key technology of the Information Superhighway, fiber optics is poised for explosive growth in the next decade. This paper identifies some of the major obstacles involved in establishing a university-level fiber optics laboratory, and suggests time-and money-saving solutions with an emphasis on pre-packaged fiber optic laboratory kits.
Characterization of chromium bearing surface alloys produced by laser alloying on low carbon steel substrates
Authors: Goswami G. L. , Kumar Dilip , Pappachan A. L. , Grover A. K. , Sridhar K.
Published: August 2012

High-chromium ferritic alloys were produced on mild steel substrates by laser surface alloying. For this, chromium-plated mild steel samples were treated with a pulsed Nd:YAG laser (300 W maximum power) by varying the average power level from 21.6 W to 30.0 W. The chromium content of the surface alloys was in the range of 3.0–27.0 wt%, with fairly uniform depth of alloying. Microscopy showed very fine austenite needles within elongated/equiaxed ferrite grains in the laser-alloyed zone (LAZ). X-ray diffraction indicated several peaks, which were identified as being from ferrite, austenite, (CrFe)7C3 and Cr23C6. Microhardness was higher in the LAZ than in substrate and varied widely depending on the chromium content. Anodic potentiostatic polarization studies in deaerated 0.1 m Na2SO4 solution showed improvement in corrosion resistance over mild steel by several orders of magnitude. Increasing chromium content in the LAZ caused shifting of the open-circuit potential towards the more noble side and reduced the critical current density for passivation as well as the current density in the passive range.
Determination of energy absorption during laser welding by an iterative conduction method
Authors: Mimatsu Junji , Bos Jeannine A. , Kannatey-Asibu Elijah , Chen Michael M.
Published: August 2012

Energy absorption is a key process in laser welding. While there is now good qualitative empirical knowledge of the dependence of the effective absorptivity on laser power level, detailed quantitative understanding is poor. In recent years there has been considerable interest in computational modeling of the heat transfer and fluid flow phenomena during laser welding, in order to have a better understanding of the physical processes involved in determining the final microstructure, and in order to explore process control strategies to optimize materials properties. The starting point of all such modeling efforts is the assumption of an effective absorptivity, or more precisely the total energy coupling efficiency. Unfortunately, the precision of our knowledge on coupling efficiency is considerably below the precision being pursued for thermo-fluid modeling. In view of this, an experimental program has been undertaken at the University of Michigan to obtain quantitative data on coupling efficiency under typical welding conditions to further the understanding of this important process. The study makes use of workpieces instrumented with a large number of imbedded thermocouples. The temperature histories of these thermocouples during and after laser irradiation and welding are analyzed by the use of nonlinear heat conduction computations to yield the time-dependent energy deposition of the laser. Data processing methodology and selected results will be presented. It is hoped that the results will be valuable in future thermo-fluid modeling efforts and in providing the database for the theoretical understanding of the mechanism of laser energy absorption by the workpiece.
Impact resistance of adhesive joints using laser-induced shock waves
Authors: Gilath I. , Englman R. , Jaeger Z. , Buchman A. , Dodiuk H.
Published: August 2012

The impact resistance of aluminum–aluminum joint bonded with FM-73 (American Cyanamid) structural adhesive was studied using laser-induced shock waves. The adhesive joint failed in a ductile mode, showing shock absorbtion ability through plastic deformation. All stages of the impact damage were identified from threshold damage through complete sample perforation. In the theoretical study, the damage induced in the target is obtained as follows. The shock wave is modeled by an expanding stress front, which creates a void population in the laser-impacted layer and extrudes a bulge at the far surface. The calculated extent of the bulge geometry compares well with that observed by us in the metal–adhesive–metal sandwiches. The voids coalesce into macro-damage or ductile failure fracture by a mechanism which is described by percolation theory.
Laser operator training and competency assessment in the community hospital setting
Authors: Connor Michael A. , Cook Allan F.
Published: August 2012

At the 279 bed Marymount community hospital, Cleveland, Ohio, the importance of providing a safe laser environment for patients as well as staff was identified. The decision was made to cross-train all full-time RNs, LPNs, and SAs to allow flexibility in staffing all laser procedures with a qualified operator. A competency based training program was implemented, utilizing a combination of techniques to assist the adult learner. Selected video tapes were used to teach laser physics and applications. Comprehension was assessed through written and oral quizzing. Individual time was spent familiarizing trainees with the equipment and accessories. Practice setups were performed until that individual reached a comfort level satisfactory to him/her and the laser coordinator. Actual experience in the various surgical specialties was dependent upon our case load. Initially very close supervision was provided. Each trainee was gradually given more autonomy as his/her skills improved and permitted to operate the laser independently after passing our competency assessment. During the first year, each operator was given competency assessment reviews at regular intervals. This approach was found to have both strengths and weaknesses and the program was modified accordingly.
Laser machining of ablating materials — overlapped grooves and entrance/exit effects
Authors: Modest Michael F. , Ramanathan Sriram , Raiber Armin , Angstenberger Birgit
Published: August 2012

A three-dimensional conduction model has been developed to predict the transient temperature distribution inside a thick solid that is irradiated by a moving laser source, and the changing shape of single or overlapping grooves carved into it by evaporation of material. The laser may operate in CW or in pulsed mode (with arbitrary temporal intensity distribution) and may have an arbitrary spatial intensity profile. The governing equations are solved, for both constant and variable thermophysical properties, using a finite-difference method on a boundary-fitted coordinate system. Results are presented for ablative groove development, including the effects of laser entry and exit (laser scanning across the edge of the material), single and overlapped groove shapes and temperature distributions in the solid at different traverse speeds, pulsing conditions, and power levels. Experimental results were obtained for groove shapes of single and overlapped grooves, using graphite as the ablating material and employing a CW CO2 laser (10.6 μm) focused with a 5-inch (12.7 cm) lens for powers ranging from 400 to 1200 W and scanning speeds ranging from 2.5 to 10 cms−1. Comparison between experimental and theoretical results indicates good qualitative agreement between theory and experiment within the limits of the (rather large) uncertainty with which material properties are known to date.
Production of Fe–noble metal surface alloys using laser beams
Authors: Manohar M. , Albright C. E. , Wilde B. E.
Published: August 2012

A new method to produce iron-noble metal surface alloys is described. Quenched-and-tempered AISI 4135 steel was electroplated with Pd, Pt and Au and laser surface melting was carried out to produce the respective surface alloys. CW CO2 laser power levels of 50, 100 and 200 W were employed. Auger depth profiling showed that alloying was achieved with Pt and Pd at all three power levels, but only at 200 W with Au.
Crafting a Future in Science
Authors: Calabrese Barton Angela , Kang Hosun , Tan Edna , O’Neill Tara B. , Bautista-Guerra Juanita , Brecklin Caitlin
Published: August 2012

The underrepresentation of girls from nondominant backgrounds in the sciences and engineering continues despite recent gains in achievement. This longitudinal ethnographic study traces the identity work that girls from nondominant backgrounds do as they engage in science-related activities across school, club, and home during the middle school years. Building a conceptual argument for identity trajectories, the authors discuss the ongoing, cumulative, and contentious nature of identity work and the mechanisms that foster critical shifts in trajectories. The authors argue that the girls view possible future selves in science when their identity work is recognized, supported, and leveraged toward expanded opportunities for engagement in science. This process yields layered meanings of (possible) selves and of science and reconfigures meaningful participation in science.
Tobacco induced oral black lesion
Authors: Shenoy N , Ongole R , Maharjan I
Published: August 2012

Journal of College of Medical Sciences-Nepal, 2011, Vol-7, No-2, 55-56DOI: http://dx.doi.org/10.3126/jcmsn.v7i2.6684
Distribution Analysis of Freight Transportation with Gravity Model and Genetic Algorithm
Authors: Duanmu Jun , Foytik Peter , Khattak Asad , Robinson R. Michael
Published: August 2012

The application of a gravity model in freight modeling work on both short-haul and long-haul trips is discussed. A commodity-based gravity model was developed to assess the distribution of freight by long-haul trucks in southeastern Virginia. Although gravity models have been used extensively in transportation studies, little work has been done to address the special characteristics of freight transportation, such as the definition of friction factors and the differences between long-haul and short-haul trips. Results of a recent study of these and similar problems provide valuable insight into freight distribution modeling. A new calibration method that used a genetic algorithm was applied, various commodities were modeled, and the impact of the commodities on the accuracy of the gravity model was studied. Both travel time and travel distance were tested to generate the impedance for friction factors; results showed that for commodity-based long-haul models, travel times were more appropriate for friction factor calculations. In addition, results showed that the gamma function was more suitable than the exponential function for friction factor calculations. Extensive analyses of the causes of variation between observed values and the gravity model outputs are provided. The analyses and conclusions may help modelers better understand characteristics specific to freight transportation and can promote model constructions with greater accuracy and efficiency.
Alternative Solution for Addressing Failed Home Deliveries
Authors: Song Liying , Cherrett Tom , Guan Wei , Zhang Wenyi
Published: August 2012

Freight planners are becoming increasingly more concerned about the impact of failed home deliveries on additional carrier journeys (repeat deliveries) and customer trips (to retrieve goods from carrier depots). A local collection-and-delivery point (CDP) concept, which allows customers to collect their failed deliveries, has emerged as a solution for home delivery failures. Data from a 2007 customer survey across two areas along with historical delivery data provided by a major carrier company in the United Kingdom were used in a study of the problem. Nine carrier companies were interviewed to gain an understanding of current operating characteristics of carriers and the key problems encountered during delivery operations. The study quantified the transport costs for the carrier and customer trips of the conventional home delivery method, in which the carrier makes repeat deliveries in the case of first-time failure and appraises the benefits of using CDP networks for handling those failures. The results suggest that a network of CDPs would function most effectively when (a) the proportion of first-time home delivery failures is significant, (b) a significant number of people walk to their local CDP, (c) the carrier's depot is located far from the collection area and is not in a convenient location that allows the trip to be combined with another trip; and (d) there is a dense network of CDPs around the residential area.
Tracking Transportation and Industrial Production across a Nation
Authors: Du Xiaochuan , Kockelman Kara M.
Published: August 2012

With the Freight Analysis Framework as its primary data source, the RUBMRIO (random utility–based multiregional input–output) model is applied for U.S. transportation, production, and trade across more than 3,000 contiguous counties. Driven by foreign export demand, RUBMRIO uses input–output expenditure shares and a nested logit model for shipment origins and mode to simulate trade patterns of commodities among the counties. Network and export demand scenarios were examined for their effects on the distribution of trade flows and production. Changes in export demands for various commodities highlighted the importance of food and petroleum manufacturing sectors in production and labor-expenditure shifts. Transport cost reductions had greater effects on total production than did similar cost increases. The most affected U.S. counties were those centrally located. Changes in travel times along the I-40 corridor had ripple effects on trade patterns everywhere with the greatest changes observed around the corridor's midpoint.
Comparison of Parametric and Nonparametric Hazard Models for Stop Durations on Urban Tours with Commercial Vehicles
Authors: Sharman Bryce W. , Roorda Matthew J. , Habib Khandker M. Nurul
Published: August 2012

Hazard-based stop duration models for the stop duration of commercial vehicles in urban areas are presented. Passively collected GPS data were used to estimate two hazard-survival models to predict the stop duration of commercial vehicles undertaking urban pickup and delivery tours. The first was an accelerated failure-time parametric hazard model, and the second was a proportional nonparametric hazard model. Explanatory variables included time of day, population or employment density, number of stops, distance of inbound and outbound trips, and attributes of destination establishments, such as sales volume and industry classification. Models were estimated with and without establishment data because these data may not always be available for model application. Results showed that passively collected GPS data could be used to estimate stop duration models when linked with other data sources that provided appropriate explanatory variables. The parametric models were shown to outperform the nonparametric models and had higher measures of goodness of fit and better hazard distributions for stop duration.
Simulating Sustainable Urban Gateway Development
Authors: Ferguson Mark , Maoh Hanna , Kanaroglou Pavlos
Published: August 2012

The term “gateway” refers to a city, or to some transport and logistics-oriented area in a city, that is associated with goods movement in, out, and through the area. Although the definition of a gateway is typically focused on goods movement, a more holistic view is adopted with consideration of the movements of people and the environmental implications of all movements. The relevance of this view is based on the interdependence of commercial and persons mobility, because all moves are happening within the same transport network, and is based on considerations of quality of life in a gateway city. Hamilton, Ontario, Canada, was chosen to test these concepts. Hamilton had a suitable geographical location, a busy port, an international airport, good highway and railway access, and an educated labor force. The gateway prospects for Hamilton were given perspective through a study of other prominent gateways that distilled success factors. Analytical work focused on multiregional economic impact modeling to assess the direct and indirect effects of Hamilton's potential evolution as a gateway. Local-level analysis, through integrated urban modeling and simulation of scenarios, stressed the impact of gateway development on commercial goods movement, auto commuting levels, emission levels, and transit ridership. Increased emissions resulting from gateway economic development could be overcome with forward-thinking policy focused on the uncongested movement of goods and people, compact urban form, and enhanced public transit working in concert. The addition of light rail transit in Hamilton and the promotion of a compact urban form would be catalysts for sustainable local gateway development. Finally, gateway-oriented development in Hamilton will cause noticeable regional economic growth. The models that were developed can be calibrated for other cities, given appropriate data.