Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber

The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting.

Evaluation of quick tests for phosphorus determination in dairy manures

Nutrients in animal manure are valuable inputs in agronomic crop production. Rapid and timely information about manure nutrient content are needed to minimize the risks of phosphorus (P) over-application and losses of dissolved P (DP) in runoff from fields treated with manure. We evaluated the suitability of a commercial hand-held reflectometer, a hydrometer, and an electrical conductivity (EC) meter for determining DP and total P (TP) in dairy manures. Bulk samples (n = 107) collected from farms across CT, MD, NY, PA, and VA were highly variable in total solids (TS) concentration, ranging from 11 to 213gL(-1), in suspensions' pH (6.3-9.2), and EC (6.2-53.3 dS m(-1)). Manure DP concentrations measured using the RQFlex reflectometer (RQFlex-DP(s)) were related to molybdate-reactive P (MRP(s)) concentrations as follows: RQFlex-DP(s) = 0.471 x MRP(s) + 1102 (r2 = 0.29). Inclusion of pH and squared-pH terms improved the prediction of manure DP from RQFlex results (r2 = 0.66). Excluding five outlier samples that had pH < or = 6.9 the coefficient of determination (r2) for the MRP(s) and RQFlex-DP(s) relationship was 0.83 for 95% of the samples. Manure TS were related to hydrometer specific gravity readings (r2 = 0.53) that were in turn related to TP (r2 = 0.34), but not to either RQFlex-DP or MRP. Relationships between suspensions' EC and DP or TP were non-significant. Therefore, the RQFlex method is the only viable option for on-site quick estimates of DP that can be made more robust when complemented with TS and pH measurements. The DP quick test can provide near real-time information on soluble manure nutrient content across a wide range of handling and storage conditions on dairy farms and quick estimates of potential soluble P losses in runoff following land applications of manure.

Quick tests for the determination of ammonia in poultry litter

The objective of this work was to test the ability of various available quick tests to determine ammonia concentration of poultry litters. A total of 136 samples was collected from brood chambers of poultry houses. Samples were equally divided between surface samples (top 25 mm) and core samples. Samples were frozen until analysis but received no further processing. Samples were analyzed for ammonia by autoanalyzer (standard) and several quick tests (conductivity, Quantofix N-Volumeter, and Reflectoquant). In addition, samples were analyzed by near-infrared spectroscopy by scanning samples using a large-sample transport device on a FOSS-NIRSystems model 6500 (64 co-added scans from 400 to 2,498 nm). Results showed that, although ammonia could be determined with reasonable accuracy by near-infrared spectroscopy using data in the 1,100 to 2,498 nm spectral range (final calibration R2 of approximately 0.90), none of the quick tests, including near-infrared, worked as well as previously found with dairy manures. The best results were found using the Quantofix or Reflectoquant (R2 of approximately 0.75), and conductivity worked only with the core samples (R2 of approximately 0.75). It is believed that interferences due to the presence of uric acid (spectroscopy, Quantofix, and Reflectoquant) and sodium bisulfate used to treat the litter (conductivity) were the cause of the decreased accuracies as compared to results achieved previously with dairy manures.

Near- versus mid-infrared diffuse reflectance spectroscopy for determination of minerals in dried poultry manure

The objective of this study was to determine if accurate calibrations for mineral content in dried poultry manures could be developed using near- or mid-infrared spectra. Samples (n = 124) were obtained from a commercial testing laboratory along with conventionally determined values for Ca, Cu, K, Mg, Mn, P, S, and Zn. Samples were blended in a food blender, dried at 60 C, ground to 20 mesh, and scanned in the near-infrared (rotating sample cup) on a scanning monochromator. Samples were also scanned in the mid-infrared on a Fourier transform spectrometer using a custom-made sample transport. Results showed that calibrations based on nearor mid-infrared spectra were not satisfactory for the accurate determination of Ca, Cu, K, Mg, Mn, P, S, or Zn in dried poultry manures. At best, most of the calibrations would be suitable for only gross estimates, although the mid-infrared calibration for P might be suitable for some needs in which only a limited degree of accuracy was needed. Either spectral range could be used to separate dried poultry manure samples into those containing less than 3% and greater than 8% Ca but not to accurately differentiate samples within those two groupings. Finally, although the mid-infrared calibrations were the more accurate for five of the eight minerals studied, the differences between the two sets of calibrations were so varied that it would be difficult to say that one region is better for mineral content measurement.

Near-infrared diffuse reflectance spectroscopy for the analysis of poultry manures

The objective was to evaluate near-infrared diffuse reflectance spectroscopy (NIRS) for determining the composition of poultry manures. Poultry manure samples were obtained from a commercial testing laboratory along with conventionally determined analyte values for total N, NH(4)(+)-N, organic N (computed as total minus NH(4)(+)-N), minerals, and moisture. Samples were blended in a food blender and scanned in polyethylene bags on a FOSS-NIRSystems model 6500 scanning monochromator. Initial results indicated that changes had occurred in NH(4)(+)-N contents from the time of analysis, and samples were reanalyzed for NH(4)(+)-N. Using the new analyses, NIRS was able to accurately determine NH(4)(+)-N, organic N, total N, and moisture in 128 poultry manures. Results were more accurate when determinations were made on an "as is" as opposed to dry matter basis. Finally, results indicated that NIRS was not suitable for the determination of minerals (P, K, Ca, etc.) in poultry manures.

Mid-infrared diffuse reflectance spectroscopy for the quantitative analysis of agricultural soils

Soil samples were analyzed conventionally and by mid-infrared diffuse reflectance spectroscopy for total C, total N, pH, and measures of biological activity. Ground, non KBr diluted, samples (n = 180) from experimental plots (two locations, three replicate plots, under plow and no-till practices, three rates of N fertilizer, and from five depths) were scanned from 4000 to 400 cm(-1) (4-cm(-1) resolution, 64 co-added scans) on a DigiLab FTS-60 Fourier transform spectrometer using a custom-made linear sample transport (50 by 2 mm sample area scanned). Results using partial least-squares regression showed that accurate calibrations can be developed for the determination of a number of compositional parameters: total C, total N, pH, and many measures of biological activity. In general, the results achieved using mid-infrared spectra were at least as accurate as those found previously using near-infrared spectra and were sometimes significantly better, that is, pH.

The sign language skills classroom observation: a process for describing sign language proficiency in classroom settings

In collaboration with teachers and students at the National Technical Institute for the Deaf (NTID), the Sign Language Skills Classroom Observation (SLSCO) was designed to provide feedback to teachers on their sign language communication skills in the classroom. In the present article, the impetus and rationale for development of the SLSCO is discussed. Previous studies related to classroom signing and observation methodology are reviewed. The procedure for developing the SLSCO is then described. This procedure included (a) interviews with faculty and students at NTID, (b) identification of linguistic features of sign language important for conveying content to deaf students, (c) development of forms for recording observations of classroom signing, (d) analysis of use of the forms, (e) development of a protocol for conducting the SLSCO, and (f) piloting of the SLSCO in classrooms. The results of use of the SLSCO with NTID faculty during a trial year are summarized.

Near-Infrared spectroscopic determination of carbon, total nitrogen, and ammonium-N in dairy manures

The objective of this study was to investigate the feasibility of using near-infrared reflectance spectroscopy (NIRS) to determine nutrient concentrations in dairy manures. We assayed diverse dairy manures (n = 107), collected from dairy farms in the northeastern United States (CT, MD, NY, PA, and VA) by conventional means and NIRS for total C, total N, NH3-N, moisture, P, K, and pH. Samples were scanned from 400 to 2498 nm in polyethylene bags on a FOSS-NIR-Systems Model 6500 scanning monochromator equipped with a sample transport device. We developed calibrations using a one-out cross validation procedure under partial least-squares regression. Preliminary results showed that eight samples were outliers either because of inaccurate conventional analysis or because they were uncharacteristic (i.e., two samples had moisture content below 72%, while all others were above 78%). These outliers were removed from further consideration. Final calibration results with the remaining 99 samples demonstrated that NIRS can accurately determine the moisture (r2 = 0.945, root mean squared deviation or RMSD = 1.0%), total C (r2 = 0.950, RMSD = 0.40%), total N (r2 = 0.956, RMSD = 0.030%), and NH3-N (r2 = 0.967, RMSD = 0.013%) concentrations, but not P or K concentrations in dairy manures. In conclusion, NIRS was shown to be a viable alternative to conventional analysis procedures for determining moisture, total C, total N, and NH3-N in a very diverse set of dairy manures.

On-farm quick tests for estimating nitrogen in dairy manure

Manure nutrient analyses performed rapidly on the farm could be useful for nutrient management programs. The objective of this experiment was to evaluate six quick tests for their accuracy in estimating total manure N or NH4+-N. The quick tests included the hydrometer, electrical conductivity meter and pen, reflectometer, Agros N Meter, and Quantofix-N-Volumeter. The hydrometer was used to estimate total N, while the remaining tests were used to estimate NH4+-N. Samples (107) were collected from dairy farms in five northeastern states. Samples were analyzed for total N and NH4+-N by traditional laboratory methods and using each of the quick tests. Manure compositions ranged from 1.4 to 38.6% dry matter (DM), 0.9 to 9.5 kg/m3 total N, and 0.3 to 4.7 kg/m3 NH4+-N. The estimated concentration of total N or NH4+-N determined by each quick test was regressed against laboratory-determined values. The hydrometer did not estimate total N accurately. The strongest relationship for estimation of NH4+-N was with the Quantofix-N-Volumeter followed by the Agros N Meter, the reflectometer, and the electrical conductivity meter and pen. When the samples were split into high (>12%) and low (< or =12%) DM groups, in all cases the r2 for the regression equation was higher for the low DM group than for the high DM group. The Agros N Meter, the reflectometer, and the conductivity meter and pen did not perform well for the high DM group. These data indicate that several quick tests are viable options for measuring NH4+-N concentrations in dairy slurries and solids.

Observations on determination of dysprosium in labeled digesta samples by near infrared spectroscopy

The objective of this work was to determine whether the Dy content of ruminal digesta samples labeled by pulse-dosing intra-ruminally with Dy-labeled forages could be determined by near infrared reflectance spectroscopy. Ruminal grab samples were obtained from four steers. Equal numbers of alfalfa and orchardgrass samples were collected at 17 times (0 to 165 h) after dosing and analyzed (total of 272 samples). Dysprosium was determined by direct current plasma emission spectrometry. Spectra were obtained by scanning ground samples on a scanning monochromator. Calibrations for Dy (0 to 349.5 ppm; mean = 44.5 ppm) were carried out using both stepwise and partial least square regressions. Wavelength selections using stepwise regression included characteristic Dy wavelengths and resulted in R2 and standard error of analysis of approximately .9 and > or = 20 ppm, respectively. Partial least squares regressions, although more robust, were not significantly better. Sample ashing to increase relative Dy concentrations did not improve the results. Further investigations indicated that interference by Co marker, also present in the samples, was a problem. Although near infrared reflectance spectroscopy is capable of determining Dy in labeled forages, further work is needed to increase its accuracy.

Social contact patterns and satisfaction with retirement of women in dual-career/earner families

The authors conducted an empirical study in 1990 of 611 mature women in dual-career/earner families who are retired from a work position in the field of education. We test twelve hypotheses that relate frequency of contact, kind of social contact and perceived gap between desired and frequency of actual social contact to satisfaction with women's timing of retirement and leisure. Nine of the twelve hypotheses were confirmed. Women who have more frequent and a greater variety of social contact are more satisfied with the timing of their retirement and their leisure than those who have less contact. The wider the gap between desired and actual frequency contact with specific groups the less satisfied will women be with their leisure experience, their amount of leisure time, and their timing of retirement.

Ion trap and quadrupole mass spectra of lignin pyrolysates: how well do they compare?

Lignin samples from wheat straw, orchard grass, red clover and a synthetic lignin were subjected to pyrolysis gas chromatography/mass spectrometry using both quadrupole (QMS) and ion-trap detector (ITD). ITD mass spectra were comparable with those presented in the National Bureau of Standards (NBS) library and with those obtained by QMS as evaluated by discrepancy factors. Computer-assisted library searches for ITD spectra were successful for 22 of 47 compounds. The other 25 compounds were not present in the library. A typical program and mass spectra are shown. Statistical data are discussed.

13C CP/MAS of LDLL mixtures of amino acids

A unit cell in which three isomers are in an L configuration and one is in a D configuration is inherently asymmetrical. For LDLL mixtures of amino acids with identical chemical structures (apart from chirality), the inter- and intramolecular interactions observed from the 13C CP/MAS NMR spectra are even larger than those which have been observed with mixtures of diastereoisomers in the solid state. This occurs even though the chemical composition of these molecular clusters consists only of nearest neighbor enantiomers. Because D and L isomers have identical chemical shifts, changes in chemical shift and peak intensities of these asymmetrical solid mixtures cannot be unambiguously assigned to either the D or one of the L isomers. In LLDL mixtures of amino acids in which half is L isomers and the other half is DL isomers, the NMR spectra clearly depend upon which amino acid contains the D isomer. Any further structural interpretation of these molecular clusters is equivocal without assigning chemical shifts to the D isomer (or alternatively designated the R, [-] or [+] isomer). Both more rigorous mathematical analysis and new NMR experiments are required which link interactions at chiral centers with NMR spectra of LLDL mixtures in the solid state.

Near infrared spectroscopic analysis of forage samples digested in situ (nylon bag)

The objective was to investigate the feasibility of using near infrared reflectance spectroscopy to determine the composition of samples generated in situ. Five alfalfa and five orchardgrass hays of differing maturities were incubated for 0, 6, 24, 48, and 72 h (Experiment 1) or for 0, 2, 4, 8, 12, 24, 48, and 96 h (Experiment 2) in rumen-fistulated, lactating cows, using nylon bags. After washing to remove rumen contents, samples were analyzed using a nonrotating circular cell in a scanning monochromator. All samples then were dried at 55 degrees C and analyzed for CP and ADF by wet chemistry and rescanned in the dry state. The degree of DM digestion of the original sample was calculated from duplicate bags. Results for spectral analysis of dried samples (Experiment 1), with one-half the samples for validation, were typical of results found for dry forages. The results for scanning wet samples were less accurate than for dry ones. Analysis of samples from Experiment 2 by equations developed in Experiment 1 often resulted in extremely large biases, but these were corrected by including six samples of each forage from Experiment 2 in the calibration set (from Experiment 1) and redeveloping the equations. Although it is possible to use near infrared reflectance spectroscopy to determine the composition of wet samples generated in situ, results are more accurate if the samples are scanned after drying.