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Mechanical Properties Characterization for Polyamide Matrix Dairy Protein Composites Fabricated Using Selective Laser Sintering Process
This work investigates the viability of casein protein for manufacturing engineering
structures. Polyamide 12 (PA12) was used as a matrix for different compositions of casein up to
20 wt%. Test samples were fabricated for neat PA12 and the composites using selective laser
sintering for mechanical properties comparisons. The results show significant increases of the
tensile strengths up to 71% for the composite materials over the neat PA12. Stiffnesses also
increased up to 157%. The composite samples were embrittled in comparison with the neat PA12
samples, however, with the addition of a plasticizer, significant improvement in ductility was
obtained from near 2% to over 6% percent elongation with marginal loss in strength. The
investigation shows the dependencies of mechanical properties of the composites on the type of
filler casein and treatments.Mechanical Engineerin
EarthN: A new Earth System Nitrogen Model
The amount of nitrogen in the atmosphere, oceans, crust, and mantle have
important ramifications for Earth's biologic and geologic history. Despite this
importance, the history and cycling of nitrogen in the Earth system is poorly
constrained over time. For example, various models and proxies contrastingly
support atmospheric mass stasis, net outgassing, or net ingassing over time. In
addition, the amount available to and processing of nitrogen by organisms is
intricately linked with and provides feedbacks on oxygen and nutrient cycles.
To investigate the Earth system nitrogen cycle over geologic history, we have
constructed a new nitrogen cycle model: EarthN. This model is driven by mantle
cooling, links biologic nitrogen cycling to phosphate and oxygen, and
incorporates geologic and biologic fluxes. Model output is consistent with
large (2-4x) changes in atmospheric mass over time, typically indicating
atmospheric drawdown and nitrogen sequestration into the mantle and continental
crust. Critical controls on nitrogen distribution include mantle cooling
history, weathering, and the total Bulk Silicate Earth+atmosphere nitrogen
budget. Linking the nitrogen cycle to phosphorous and oxygen levels, instead of
carbon as has been previously done, provides new and more dynamic insight into
the history of nitrogen on the planet.Comment: 36 pages, 12 figure
Isobutyl acetate: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy and ab initio calculations
The high-resolution vacuum ultraviolet photoabsorption spectrum of isobutyl acetate, C6H12O2, is presented here and was measured over the energy range 4.3–10.8 eV (290–115 nm). Valence and Rydberg transitions with their associated vibronic series have been observed in the photoabsorption spectrum and are assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. The measured photoabsorption cross sections have been used to calculate the photolysis lifetime of this ester in the Earth’s upper atmosphere (20–50 km). Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl acetate and are compared with a photoelectron spectrum (from 9.5 to 16.7 eV), recorded for the first time. Vibrational structure is observed in the first photoelectron band of this molecule
Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV
The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0–10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) (1Δ←1Σ+) transition, with a new weak transition assigned to (1Σ−←1Σ+) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to 1Σ+ and 1Π transitions. Based on our recent measurements of differential cross sections for the optically allowed (1Σ+ and 1Π) transitions of COS by electron impact, the optical oscillator strength f0 value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20–50 km)
Evaluation of Damage by Vertebrate Pests in California Vineyards and Control of Wild Turkeys by Bioacoustics
Complaints of agricultural damage by wild turkeys (Meleagris gallopavo), particularly from wine grape growers, have increased in California. We assessed damage by vertebrate pests in vineyards and tested a bioacoustic-aversion technique for turkeys as an alternative to other control techniques (e.g., reflective tape, trapping, bird netting). We selected 12 vineyards in the Napa Valley and Sierra Foothills American Viticultural Areas of California. We conducted damage surveys to assess percentages of missing or damaged grapes (i.e., grapes that had been stripped, pecked, and plucked) for every grape cluster on 20 randomly-selected vines before harvest in 2007 and on 40 vines in 2008. We assumed that all observed damage was caused by vertebrate pests and that most of this damage was caused by birds. Grape damage caused by wild turkeys was identified by contiguous sections of berries plucked from a cluster, which we referred to as stripped damage. We attributed pecked and plucked damage to passerines. In 2008, we randomly selected 3 vineyards in each area for treatment with broadcast calls (wild turkey alarm, domestic turkey alarm, crow distress). We used motion-activated video cameras to document evidence of damage caused by turkeys and other animals. Damage in the vineyard perimeter was greater than in the interior for all damage types in 2008, but only for plucked damage in 2007. In 2008, stripped, pecked, and plucked damage means for treated vineyards were 1.3%, 1.4%, and 1.5%, respectively; stripped, pecked, and plucked damage means for untreated vineyards were 1.3%, 0.7%, and 0.2%, respectively. There was no difference in mean stripped damage between treated and untreated vineyards in 2008, indicating that broadcast calls had no effect. Comparison between treated sites in 2008 with the same untreated sites in 2007 yielded similar results. Turkeys caused damage in several of the study vineyards, but the problem varied among vineyards and was inconsistent between years. Motion-activated video recordings suggested that raccoons (Procyon lotor), gray foxes (Urocyon cinereoargenteus), and other vertebrate pests were to blame for some of the stripped damage
StomateTutor™: An Introduction to Stomatal Control of Gas Exchange in Plants
This is a HyperCard implementation which includes Pascal programs. HyperCard, which requires at least 1 Megabyte of memory, must be supplied by the user. The system disk must include the Geneva 10 pt font. When using, open the HyperCard stack StomateTutor which coordinates the remaining files (StomateTutorl-3 and the two Pascal programs). When you run StomateTutor the first time with your file configuration, you must locate the Pore Width and Diffusion applications used in Modules 1 and 2, respectively
Algumas exigências metabólicas de Pseudomonas denitrificans
The experiment described herein was performed in order to establish a completely synthetic medium for growing P. denitrificans cells. In order to obtain in 48 hr. a growth as good as that obtained with the control cultures (with yeast extract), the medium must be formed by micronutrients, the inorganic salts No2SO4, MgSO4 and (NH4)2SO4,and by an amino acid such as sodium glutamate. The KNO3 is for course needed in order to proporcionate the nitrate, and the medium must be buffered with 1M potassium phosphate buffer, pH 6.8. Succinate serves as a substrate. The role of glutamate is under investigation.Para estudos da bioquímica da desnitrificação os desnitrificadores são cultivados em meio parcialmente sintético, com extrato de levedura ou de carne ou ainda peptona. Procurou-se então um meio de cultura completamente sintético no qual P. denitrificans pudesse desenvolver-se e fazer desnitrificação. Para tanto, células de um "strain" dessa bactéria foram crescidas durantes, 24 e 48 horas em tubos de ensaio contendo 10 ml de meio de cultura consistindo de succinato de sódio, nitrato de potássio, extrato de levedura o tampão de fosfato 1M, valôr pH 6,8. Dêsse meio (controle) 0,1 ml foi inoculado em 10 ml do meio de cultura em estudo, mantido então em condições parcialmente anaeróbicas. Após 24 horas uma alíquota foi retirada e suspensa em água destilada e a turbidês lida em espectrofotômetro Beckman, a 420 my. Os dados obtidos após longa série de ensaios permitiram concluir que a fim de se obter em 48 horas um crescimento da mesma ordem que o obtido com o meio controle, o meio de cultura sintético deve conter micronutrientes (Zn, Fe, Mn, Cu, Co, B e Mo, em EDTA), sulfato de sódio, sulfato de magnésio e ácido glutâmico, além de KNO3, succinato e tampão de fosfato
Ecological interactions and coexistence are predicted by gene expression similarity in freshwater green algae
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136696/1/jec12759_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136696/2/jec12759.pd
Fixação do dióxido de carbono por bactérias nitrificantes
During the oxidation of the substrate, both Nitrosomonas and Nitrobacter have part of the energy made available as high energy phosphate, mamely ADP and ATP. This chemical energy is used to fix CO2. The nature of the reducing power is unknown at present. Active cells of Nitrobacter were shown to fix CO2 along the same pathway as found in higher plant photosynthesis. Sonic extracts of Nitrosomonas and Nitrobacter when incubated with NaH14CO3 and cofactors showed two ports of entry of CO2 into organic compounds one being, as expected, the carboxidismutase reaction. On protein basis an equivalent amount of CO2 was, however, incorporated via the oxaloacetic carboxylase reation. It is clear then that both micoorganisms possess typical autotrophic and heterotrophic mechanisms for the fixation of CO2 which is required for the primary synthesis of cell material
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