bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental-Numerical Approach for Characterization of Mechanical Properties of Thin Electrochemically Deposited Chromium and Copper Films
Authors: Cherneva Sabina , Yordanov Milko , Stoychev Dimitar , Iankov Rumen
Published: March 2010

A hybrid experimental-numerical approach, which combines microindentation experiments (where we measure the diagonal of the residual imprint after unloading) and numerical simulations by means of the finite-element method has been developed. The investigated materials in the present work are electrochemically deposited on brass substrates chromium and copper films with known thickness and unknown mechanical properties. Mechanical properties of the brass (CuZn36) substrate are known. Vickers’ microindentation experiments were carried out on the films and as a result the experimental load-displacement curves were obtained. After that the process of microindentation was modelled numerically by means of the finite-element method. Numerically obtained load-displacement curves were compared with the experimental curves. The results show good coincidence between numerical and experimental curves. Additionally it was realized nanoindentation experiment of thin copper film and these two methods (nanoindentation experiment and hybrid experimental-numerical method which combines experiment of microindentation and numerical simulations) for determination of mechanival properties of thin copper films were compared. Results obtained by means of the afore-mentioned two methods almost coincide but the second method is cheaper and gives more information about material properties of the film than the first method. It is shown that the second method is preferable to determine the mechanical properties of thin metal films.
Investigations of Plasma-Chemically Produced Nanodispersed Si3N4 for Modification of Tool Steels
Authors: Yordanov Boyan , Krastev Dimitar
Published: March 2010

The nanodispersed nitrides are applied in various technological and industrial fields. One of them is the use for modification of special steels and alloys. Results from metallographic investigation on the microstructure and properties of the alloyed in nitrogen tool steel, type X210Cr12 after modification with nanodispersed Si3N4 are presented in this paper.
Surface Debye Temperatures and Specific Heat of Nanocrystals
Authors: Michailov Michail , Avramov Isak
Published: March 2010

The present study deals with the contribution of the surface atomic layer to the specific heat of nanocrystals. In the case of small phases with comparable number of bulk and surface atoms, the variation of heat capacity with respect to that of infinitely large phase is significant. To evaluate this variation, in the framework of the classical Debye model, we introduce surface excess heat capacity that accounts for the surface layer contribution. On that physical background, we draw a functional dependence of the specific heat of nano clusters on the number of their bulk and surface atoms and corresponding bulk, , and surface, , Debye temperatures. Since depends on the crystallographic orientation of the surface, the presented model also accounts for the symmetry and atomic density of the respective crystal faces of the nanocrystal.
Effects of Substitution in Barium Hexaferrites BaFe12-xXxO19 (X=Co,Ti; Sc)
Authors: Krezhov Kiril
Published: March 2010

The short and long-range atomic and magnetic order in BaFe12-xCoxTixO19 (x=0.4, 0.7, 0.8) and BaFe10.4Sc1.6O19 prepared by soft chemistry routes were studied and compared with parent BaFe12O19 prepared by solid-state reaction. For BaFe10.3Co0.85Ti0.85O19 neutron diffraction and magnetic measurements revealed that (Co2+, Ti4+) substitution causes significant distortions in the local oxygen surrounding of ferric cation sites, while the grain-size effect on the structural parameters is considerably smaller. The thermal expansion coefficient exhibits a strong anisotropy. The refined magnetic moments for x=0.45 and 0.7 based on the five-cation sublattice block-type collinear ferrimagnetic structure of uniaxial type known as Gorter type for BaFe12O19, are considerably lower than the theoretical spin only moments, especially for the 4e and 12k sites, indicating for x = 0.7 a local noncollinearity with short-range ordering. For x = 0.85, at 10 K a block-type conical magnetic structure sets in. For BaFe10.4Sc1.6O19, combined neutron diffraction, field-dependent 57Fe Mössbauer studies and magnetic measurements show that the collinear block-type structure remains effective at 300 K and below it down to about 190 K. In the 190 – 1.6 K range we observe a temperature dependent incommensurate complex block-type conical structure.
Some Medical Applications of Nanomaterials
Authors: Lovchinov Vassil , Simeonova Pavlina , Radulov Iliya , Nedkov Ivan , Kalionsky Rumen
Published: March 2010

The aim of the present study is to demonstrate some opportunities in targeted drug delivery using nanotechnology and nanomaterials. We report here the successful development of a contrast agent and media for hypothermal processes using our own synthetic method for SPIO nanoparticles and a cyclodextrin coating
It’s a Long Way to “Superhard” Semiconductors
Authors: Brylinski Christian
Published: March 2010

Because of strong synergy with information technology, visible light imaging, and solar cell businesses, most of the devices for medium and high voltage power electronics are based on silicon in year 2009 [1]. Still we know, for more than 50 years, that “harder” semiconductors, exhibiting higher breakdown electric field, would be preferable [2]. On the way towards the development of such new materials, the road is very narrow between so many intricate scientific and technical obstacles. After 50 years of SiC technology development, a first generation of reliable Schottky rectifiers is now available [3,4], but it will take time to turn it into a profitable business. Despite of very important progress over the past 15 years, it is not yet clear whether there will ever be any reliable high voltage switching device based on SiC MOS [5-7]. Vertical JFET have recently appeared as realistic alternative solutions [9-12]. Hetero-epitaxial GaN materials on sapphire or silicon substrate may appear as competitors to SiC. Progress on the crystal growth of Diamond, Aluminum Nitride [8] and Boron Nitrides for electronics is on the way, but there is no convincing solution identified yet for the basic doping problems. Regarding the more ionic II-VI or I-VII semiconductors, very few people still believe that they can play a role inside future device structures for power electronics.
AlGaN/GaN Based Heterostructures for MEMS and NEMS Applications
Authors: Cimalla Volker , Röhlig C. C. , Lebedev V. , Ambacher Oliver , Tonisch Katja , Niebelschütz Florentina , Brueckner Klemens , Hein Matthias A.
Published: March 2010

With the increasing requirements for microelectromechanical systems (MEMS) regarding stability, miniaturization and integration, novel materials such as wide band gap semiconductors are receiving more attention. The outstanding properties of group III-nitrides offer many more possibilities for the implementation of new functionalities and a variety of technologies are available to realize group III-nitride based MEMS. In this work we demonstrate the application of these techniques for the fabrication of full-nitride MEMS. It includes a novel actuation and sensing principle based on the piezoelectric effect and employing a two-dimensional electron gas confined in AlGaN/GaN heterostructures as integrated back electrode. Furthermore, the actuation of flexural and longitudinal vibration modes in resonator bridges are demonstrated as well as their sensing properties.
Some Recent Results on the 3C-SiC Structural Defects
Authors: Marinova Maya , Mantzari Alkyoni , Polychroniadis Efstathios K.
Published: March 2010

This work presents some recent results on the 3C-SiC structural defects, studied by Transmission Electron Microscopy (TEM). The samples studied were grown in several laboratories, using different methods. Commonly used methods for growth are Sublimation Epitaxy (SE), Physical Vapour Transport (PVT), Continuous Feed Physical Vapour Transport (CF-PVT), Chemical Vapour Deposition (CVD), and Liquid Phase Epitaxy (LPE). In all these methods, for both bulk and epitaxial layer growth, substrates from other polytypes are exploited like the common hexagonal polytypes 4H- and 6H-SiC or 3C-SiC seeds both in (111) and (100) orientation.
Ultrananocrystalline Diamond / Amorphous Carbon Composite Films – Deposition, Characterization and Applications
Authors: Popov Cyril , Kulisch Wilhelm , Petkov Christo , Reithmaier Johann Peter
Published: March 2010

UNCD/a-C composite films have been deposited by microwave plasma chemical vapour deposition from methane/nitrogen mixtures with 17% CH4 in the temperature range 500-770°C on various substrates such as monocrystalline silicon wafers, polycrystalline diamond, c-BN, TiN, GaAs, and other materials of technological interest. The resulting films have been thoroughly characterized with respect to their morphology, crystallinity, composition, and bonding structure. It was found that they are composed of diamond nanocrystallites (3-5 nm in diameter) surrounded by 1-1.5 nm amorphous carbon grain boundary material; the ratio of the volume fractions of crystalline and amorphous phase is close to unity. The investigations of the application-relevant properties of the UNCD/a-C films revealed that they are attractive for a number of mechanical, tribological, structural, and biomedical applications.
Structural and Magnetic Properties of Nanosized Barium Hexaferrite Powders Obtained by Microemulsion Technique
Authors: Koutzarova Tatyana , Kolev Svetoslav , Grigorov Kornely Grigoriev , Ghelev Chavdar , Zaleski Andrzej , Vandenberghe Robert E. , Ausloos Marcel , Henrist Catherine , Cloots Rudi , Nedkov Ivan
Published: March 2010

Thin hexagonal barium hexaferrite particles synthesized using the microemulsion technique were studied. A water-in-oil reverse microemulsion system with cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, n-butanol as a co-surfactant, n-hexanol as a continuous oil phase, and an aqueous phase were used. The microstructural and magnetic properties were investigated. The particles obtained were mono-domain with average particle size 280 nm. The magnetic properties of the powder were investigated at 4.2 K and at room temperature. The saturation magnetization was 48.86 emu/g and the coercivity, 2.4 x 105 A/m at room temperature. The anisotropy field Ha and magneto-crystalline anisotropy K1 were 1.4 x 106 A/m and 2.37 x 105 J/m3, respectively.
Deposition and Characterization of Aluminium Nitride (AlN) and Diamond Like Carbon (DLC) Hard Coatings
Authors: Mednikarov B.
Published: March 2010

Traditionally, the term hard coatings refer to the property of high hardness in mechanical sense with good tribological properties [1]. With the development of modern technology in the areas of optical, optoelectronic, microelectronic and related defense applications, the definition of the term hard coatings can be extended. Thus, a system which operates satisfactorily, in a given environment can be said to be hard with respect to that environment [2]. Most of the hard coatings are ceramic compounds such as oxides, carbides, nitrides (AlN), ceramic alloys, cermets, metastable materials such as Diamond-Like Carbon (DLC). Their properties and environmental resistance depend on the composition, stoichiometry, impurities, microstructure, imperfections, and in the case of coatings, the preferred orientation (texture).
In this paper we shall take a look at some characteristics - physicochemical and optical of AlN and DLC layers synthesized by physical vapor deposition – RF magnetron sputtering in an industrial high vacuum deposition system. The influence of the process parameters on the growth rate, morphology, topography and chemical bonding structure will be presented.
Modeling of the Light Emission Spectra of InGaN/GaN Quantum Well with Highly Doped Barriers
Authors: Arnaudov Boris , Domanevskii Dmitrii S. , Evtimova Svetla , Ivanov Chavdar , Kakanakov Roumen
Published: March 2010

We investigate light emission spectra at different excitation levels of nanoscale thin InGaN film participating in an InGaN/GaN quantum well (QW) with heavily doped barriers for green and blue light emitting diodes (LEDs). We model the spectral shape and energy position in frames of the free electron recombination model created first for highly doped 3D direct gap III-V semiconductor films and applied for QWs at low excitation. The model accounts for the influence on the potential width of the QW of the random impurity potential of the doped barriers which penetrates into the QW. The blue shift at high excitation is supposed to be due to the filling of the conduction band with degenerate 2D nonequilibrium electrons. A structure in the emission bands is observed and it is assumed to be a result from step-like 2D density-of-states (DOS) in the QW. A good agreement is obtained between the calculated and experimental spectra assuming that the barriers are graded.
Search for a Suitable Ohmic Metallization Scheme to GaN/AlGaN Heterostructures for Sub-Micron Devices
Authors: Kolaklieva Lilyana , Kakanakov Roumen , Chitanov V. , Dulgerova Polina , Cimalla Volker
Published: March 2010

Ohmic properties, thermal stability and surface morphology of Al-based and non-aluminium metallizations are investigated in dependence on the annealing temperature and initial composition. Non-aluminium contacts show poor ohmic properties, while contact resistivity of 3.47x10-5 Ω.cm2 is achieved for Ti/Al/Ti/Au metallization with a former-Ti/Al ratio of (30 wt.% /70 wt.%).
Thermal properties of the Al-based metallization are improved by application of Mo layer as a barrier under the upper Au film of the contact structure. These contacts show excellent thermal stability at operating temperatures as high as 400oC. The less Al amount in the contact composition and Mo barrier layer contribute to the smoother surface and better edge acuity.
High-Quality GaInAsSb and GaAlAsSb Layers for Thermophotovoltaics Grown by Liquid-Phase Epitaxy
Authors: Milanova M. , Kakanakov Roumen , Koleva G. , Vitanov P. , Bakardjieva V. , Zamoryanskaya M.V. , Popova T.P.
Published: March 2010

GaSb based III-V heterostuctures are attractive for optoelectronic devices such as midin- frared lasers, detectors, and thermophotovoltaics (TPVs).
In this paper the growth and characterization of GaInAsSb and GaAlAsSb quaternary layers, lat-tice-matched to GaSb substrate, are reported, with a particular focus on these alloys for TPV devi-ces. High-quality with a mirror-like surface morphology epilayers Ga1-x InxAsy Sb1-y with In content x in the range 0.1-0.22 and Ga1-xAlxAsySb1-y layers with Al content up to 0.3 in the solid are grown by Liquid-Phase Epitaxy (LPE) from In- and Ga-rich melt, respectively.
The compositions of the quaternary compounds are determined by X-ray microanalysis. The crystalline quality of GaInAsSb/ GaSb and GaAlAsSb/GaSb heterostuctures is studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements.
A High Effective Selective Absorbing Coating for Solar Thermal Collectors
Authors: Kirilov Rumen , Stefchev P. , Alexieva Z. , Dikov H.
Published: March 2010

High effective selective absorbing bimetallic structures of Sn and Ni for solar thermal collectors have been investigated. They were produced by cathode electrodeposition on polished copper plates from water solution. Scanning electron microscopy micrographs show that they consist of a highly branching layer of bimetallic needles. They serve as a radiation trap for the solar radiation because of multiple reflections. The reflectance spectra were measured in the visible and infrared range. The absorptance of the coating was calculated as 98% in the solar radiation range and the thermal emittance in the infrared region at 100 °C - as 10%. The selective absorbing coatings are investigated by X-ray diffraction analysis and X-ray photoеlectron spectroscopy as well as optical spectra in the UV-VIS and IR region. The samples with selective absorbing coatings have been tested at natural solar radiation. The results show that the new coatings have substantial advantages in comparison to the widely used black chrome.
Two- and Three-Dimensional EBSD Measurement of Dislocation Density in Deformed Structures
Authors: Field David P. , Merriman Colin C. , Mastorakos Ioannis N.
Published: March 2010

Electron backscatter diffraction (EBSD) techniques have been used to measure the dislocation density tensor for various materials. Orientation data are typically obtained over a planar array of measurement positions and the minimum dislocation content required to produce the observed lattice curvature is calculated as the geometrically necessary (or excess) dislocation density. The present work shows a comparison of measurements in two-dimensions and three-dimensions using a dual beam instrument (focused ion beam, electron beam) to obtain the data. The two-dimensional estimate is obviously lower than that obtained from three-dimensional data since the 2D analysis necessarily assumes that the third dimension has no curvature in the lattice. Effects of the free-surface on EBSD measurements are discussed in conjunction with comparisons against X-ray microdiffraction experiments and a discrete dislocation dynamics model. It is observed that the EBSD measurements are sensitive to free-surface effects that may yield dislocation density observations that are not consistent with that of the bulk material.
Determination of the Orientation Relations between the Low- and High-Temperature Phases of NiS
Authors: Sowa Heidrun , Klein Helmut , Raue Lars
Published: March 2010

In order to get information about the transition mechanism, the temperature-induced transformation in the binary com¬pound NiS was investigated. Above 379 °C, a single crystal of millerite -NiS transforms to polycrystalline NiAs type -NiS with a sharp texture. Pole figures of both phases in the same orientation were measured using synchrotron radiation and an imaging plate detector. The Rietveld texture analysis showed that there are at least three components of the high-temperature -NiS phase. The main component shows the following orientation relations:
[001]NiAs type  [001]millerite, [100]NiAs type  [210]millerite, [210]NiAs type  [100]millerite.
The broad peaks of the recovered polycrystalline millerite occur at the same positions as the reflections of the original single crystal.
Nucleation and Growth of Surface Texture during α-γ-α Transformation in Ultra Low Carbon Steel Alloyed with Mn, Al and Si
Authors: Gautam Jai , Petrov Roumen H. , Leunis Elke , Kestens Leo
Published: March 2010

. It is well known that surface energy anisotropy is one of the driving forces for the orientation selection at the metal-vapour interface. This affects the microstructure and texture evolution at the surface during phase transformation, which is an inherent feature of low-alloyed low-carbon steels. This paper investigates the nucleation and growth of the surface texture by orientation contrast microscopy. It has been found that the surface texture is dominated by {001} oriented grains, which exhibit a remarkable orientation gradient from the centre of the grain towards the edge. The {001} oriented grain centre gradually rotates around a <110> axis in small incre¬mental steps when nearing the edge of the grain. Towards the edge the accumulated rotation angle has commonly reached a value of 30°. Underneath the surface grains (~30 µm) the bulk texture consists of a strong -fibre.
Influence of MnS Particles inside Grains on the Boundary Migration before Secondary Recrystallization of Grain Oriented Electrical Steels
Authors: Mao W. , Li Y. , Guo W. , An Z.
Published: March 2010

The precipitation behaviors of fine MnS and other second phase particles in hot band, decarburized sheet and 875 oC annealed sheet before secondary recrystallization of conventional grain oriented electrical steel were investigated. It is indicated that the small particles as inhibitors would dissolve in the matrix during cold rolling, and precipitate again in following annealing treatment. The particles inside grains would keep retarding the grain boundary migration. It was found that the particle densities in all grains were quite different before initiation of secondary recrystallization and might be grain orientation dependent, in which Goss grains showed higher particle density. It is expected that the grain boundaries would move towards the grains with lower particle density more easily and promote the rapid growth of Goss grains. The reason for difference of particle densities in different grains is quite complicated. The influence of possible different dislocation densities and the different precipitation behaviors of second phase particles are mentioned.
Microstructure Investigation of the PVD Thin Films of TRIP Steels
Authors: Poklad A. , Klemm V. , Schreiber G. , Wüstefeld C. , Rafaja David
Published: March 2010

The combination of a TRIP steel with the MgO stabilized ZrO2 ceramics (MgO•ZrO2) is regarded as a promising way to increase the energy absorption in engineering materials. An additional contribution to the energy absorption in the counterparts, i.e. in the TRIP steel and in MgO•ZrO2, is expected to arise at the interfaces between the individual materials. However, the mutual crystallographic orientation of the TRIP steel and MgO•ZrO2 at their interface plays a crucial role both for the adhesion of the counterparts and for the energy absorption process. In this work, the interfaces between the TRIP steel and MgO•ZrO2 were studied on simplified systems, which were prepared in form of the TRIP steel thin films that were deposited using the magnetron sputtering on various substrates, e.g. Si wafer, MgO•ZrO2 and the Al2O3/ZrO2 composites. The substrates were both single-crystalline (Si wafer) and polycrystalline (MgO•ZrO2, Al2O3/ZrO2). The basic characteristics of the thin films (morphology, thickness, chemical composition) were obtained from the scanning electron micrographs and from the energy dispersive analysis of the characteristic X-rays (EDX). X-ray diffraction (XRD) and transmission electron microscopy with high-resolution (HRTEM) that was complemented by the Fast Fourier Transform (FFT) of the HRTEM micrographs were employed as the crucial experimental methods for the microstructure analysis of these thin films. XRD was used for the phase analysis and for the global texture analysis. The global texture analysis was performed via the pole figure measurements. FFT/HRTEM was used for the characterisation of the local orientation relationships between the TRIP steel and the respective substrate and for the visualisation of the interfaces between individual crystallites.
Application of Electron Backscatter Diffraction to Grain Boundaries
Authors: Randle Valerie
Published: March 2010

The technique of electron backscatter diffraction (EBSD) is ideal for the characterisation of grain boundary networks in polycrystalline materials. In recent years the experimental methodology has evolved to meet the needs of the research community. For example, the capabilities of EBSD have been instrumental in driving forward the topic of ‘grain boundary engineering’. In this paper the current capabilities of EBSD for grain boundary characterisation will be reviewed and illustrated by examples. Topics are measurement strategies based on misorientation statistics, determination of grain boundary plane distributions and grain boundary network characteristics.
Magnetic Quantitative Texture Analysis Using Isotropic Thermal Neutron Beams
Authors: Chateigner Daniel , Ouladdiaf B. , Léon Francois
Published: March 2010

We give the necessary formulas to extract pure magnetic diffraction signals from the difference spectra between two neutron texture measurements, one operated with a sample at zero-magnetic field, and the other under a magnetic field. This enables us to calculate the total-magnetic-scattering ODF, and the polarisation-magnetic-scattering ODF, of an iron sample. Using the developed approach it is shown that under some hypotheses one can describe the three dimensional orientation of the magnetic moments in the sample under a given magnetic field.
Influence of the Crystallographic and the Morphological Texture on the Elastic Properties of Fcc Crystal Aggregates
Authors: Jöchen K. , Böhlke Thomas , Fritzen F.
Published: March 2010

In this contribution, the prediction of the self-consistent homogenization method with regard to the effective material response of cubic crystal aggregates is analyzed and compared to results from full field simulations. The influence of the crystalline orientation distribution but also the effect of the grain shape on the macroscopic elastic response of sheet metals is especially emphasized.
Expression of Functional D299G.T399I Polymorphic Variant of TLR4 Depends More on Coexpression of MD-2 Than Does Wild-Type TLR4
Authors: Prohinar Polonca , Rallabhandi Prasad , Weiss Jerrold P. , Gioannini Theresa L.
Published: March 2010

Two missense variants (D299G and T399I) of TLR4 are cosegregated in individuals of European descent and, in a number of test systems, result in reduced responsiveness to endotoxin. How these changes within the ectodomain (ecd) of TLR4 affect TLR4 function is unclear. For both wild-type and D299G.T399I TLR4, we used endotoxin⋅CD14 and endotoxin⋅MD-2 complexes of high specific radioactivity to measure: 1) interaction of recombinant MD-2⋅TLR4 with endotoxin⋅CD14 and TLR4 with endotoxin⋅MD-2; 2) expression of functional MD-2⋅TLR4 and TLR4; and 3) MD-2⋅TLR4 and TLR4-dependent cellular endotoxin responsiveness. Both wild-type and D299G.T399I TLR4ecd demonstrated high affinity (Kd ~ 200 pM) interaction of endotoxin⋅CD14 with MD-2⋅TLR4ecd and endotoxin⋅MD-2 with TLR4ecd. However, levels of functional TLR4 were reduced up to 2-fold when D299G.T399I TLR4 was coexpressed with MD-2 and >10-fold when expressed without MD-2, paralleling differences in cellular endotoxin responsiveness. The dramatic effect of the D299G.T399I haplotype on expression of functional TLR4 without MD-2 suggests that cells expressing TLR4 without MD-2 are most affected by these polymorphisms.
Single-Chain HLA-A2 MHC Trimers That Incorporate an Immundominant Peptide Elicit Protective T Cell Immunity against Lethal West Nile Virus Infection
Authors: Kim Sojung , Li Lijin , McMurtrey Curtis P. , Hildebrand William H. , Weidanz Jon A. , Gillanders William E. , Diamond Michael S. , Hansen Ted H.
Published: March 2010

The generation of a robust CD8+ T cell response is an ongoing challenge for the development of DNA vaccines. One problem encountered with classical DNA plasmid immunization is that peptides produced are noncovalently and transiently associated with MHC class I molecules and thus may not durably stimulate CD8+ T cell responses. To address this and enhance the expression and presentation of the antigenic peptide/MHC complexes, we generated single-chain trimers (SCTs) composed of a single polypeptide chain with a linear composition of antigenic peptide, β2-microglobulin, and H chain connected by flexible linkers. In this study, we test whether the preassembled nature of the SCT makes them effective for eliciting protective CD8+ T cell responses against pathogens. A DNA plasmid was constructed encoding an SCT incorporating the human MHC class I molecule HLA-A2 and the immunodominant peptide SVG9 derived from the envelope protein of West Nile virus (WNV). HLA-A2 transgenic mice vaccinated with the DNA encoding the SVG9/HLA-A2 SCT generated a robust epitope-specific CD8+ T cell response and showed enhanced survival rate and lower viral burden in the brain after lethal WNV challenge. Inclusion of a CD4+ Th cell epitope within the SCT did not increase the frequency of SVG9-specific CD8+ T cells, but did enhance protection against WNV challenge. Overall, these findings demonstrate that the SCT platform can induce protective CD8+ T cell responses against lethal virus infection and may be paired with immunogens that elicit robust neutralizing Ab responses to generate vaccines that optimally activate all facets of adaptive immunity.
A METHOD FOR THE EXTRACTION OF PIGMENTS (CHROMOGENS) FROM FECES OF CATTLE AND SHEEP
Authors: Brisson Germain J. , Hatina George
Published: March 2010

A rapid and simple method is described for the routine determination of chromogen in feces of cattle and sheep. Fresh feces, sheep 2 gm. and cattle 3.5 gm., are macerated with 5 ml. acetone, transferred quantitatively into a Bailey-Walker siphon cup, and extracted with 1000 ml. 85 per cent acetone flowing continuously over the sample at the rate of 10 to 12 ml. per minute. Absorbance of appropriate dilution (5 or 10 ml. aliquot diluted to 50 ml.) of the extract is determined at 413 mμ and the chromogen content per unit dry matter is calculated.
EFFECTS OF LOW FLUCTUATING TEMPERATURES ON FARM ANIMALS: II. INFLUENCE OF AMBIENT AIR TEMPERATURE ON WATER INTAKE OF LACTATING HOLSTEIN-FRIESIAN COWS
Authors: MacDonald M. A. , Bell J. M.
Published: March 2010

The effects of low fluctuating temperatures on water intake and on the ratios of water intake to various other factors are reported. Six mature lactating Holstein-Friesian cows were confined in stanchions for three 14-day experimental periods during which temperatures, measured in degree-hours per day (d-h/day), ranged from 110 to 1152 and daily minimum ambient air temperatures (DMAAT) varied from 0° to 38° F. An interim period of approximately 14 days separated each test period. Each cow received hay ad libitum and concentrates were fed according to level of milk production and live weight. Each cow was watered individually five times daily and water consumption was recorded.Correlations of free water consumption and total water intake with both d-h/day and DMAAT were significant at the 2 per cent level in each case. Regressions of free water consumption and total water intake during the subsequent day on d-h/day were both significant at the 3 per cent level but regressions of the same factors on DMAAT were only significant at the 8 per cent level for free water consumption during the subsequent day and the 9 per cent level for total water intake during the subsequent day. Low fluctuating temperatures did not affect any of the ratios analysed to a significant extent. Thus, as d-h/day increased and DMAAT decreased, water intake increased. The increases were concomitant with increased feedstuffs intakes.Results of this study support Adolph’s hypothesis that the water requirement of mammals is roughly one millilitre per Calorie of heat produced. Temperature had no significant effect on this ratio. The correlation between water intake and caloric intake was significant at the 2 per cent level.Thermal stress effects experienced by the cows in response to temperature changes appeared to be dissipated within 24 hours, or overshadowed by the more immediate effects of the environment the following day.
NUTRIENT REQUIREMENTS FOR CANADIAN YORKSHIRE SWINE: II. THE EFFECTS OF BARLEY AND OAT FINISHING RATIONS ON RATE OF GAIN, FEED UTILIZATION AND CARCASS QUALITY OF PIGS MARKETED AT 185 AND 200 POUNDS LIVEWEIGHT
Authors: Bell J. M. , Bowland J. P. , Cameron C. D. T. , Crampton E. W. , Lloyd L. E. , Seale M. E. , Whiting F.
Published: March 2010

Four stations co-operated in a statistically analysed feeding trial to compare barley and oats in self-fed finishing rations. Pigs fed barley gained 0.25 lb. more per day, consumed more TDN and calories daily, had higher dressing percentages, and received lower commercial grades for carcass quality. They had more back fat but Advanced Registry (AR) scores were not significantly different.There was no improvement in commercial grades or AR scores when pigs were slaughtered at 185 instead of 200 lb. liveweight, although lighter pigs had less back fat. Significant differences between stations demonstrate importance of considering genetic and environmental influences when interpreting results of nutrition studies.
DRY MATTER LOSS AND VOLATILE FATTY ACID PRODUCTION IN THE ARTIFICIAL RUMEN AS INDICES OF FORAGE QUALITY
Authors: Asplund J. M. , Berg R. T. , McElroy L. W. , Pigden W. J.
Published: March 2010

Procedures are described for determining dry matter losses and for measuring volatile fatty acid production by direct chromatographic separation of acids produced during incubation of finely ground forages in miniature artificial rumen units. The results of preliminary assays done on three samples of unknown digestibility—excellent alfalfa hay, good mixed grass-alfalfa hay, and oat straw—showed that significantly different percentages of dry matter were lost and significantly different amounts of fatty acids were produced when feeds of such diverse quality were fermented. Analysis of the data for two groups of 11 and 6 samples of hay, for which dry matter digestibility coefficients as determined with sheep were available, indicated the existence of a high degree of correlation between dry matter digestibility in vivo and both dry matter loss and fatty acid production in vitro. Differences in assay results were observed when filtered rumen fluid or washed cells from the rumen fluid of sheep fed hay or from sheep fed straw were employed as sources of inocula. Examples of unsolved problems which are pertinent to the appraisal of the efficacy of artificial rumen assays for the estimation of the nutritive value of forages are discussed.
INTERPRETATION OF INTERACTION IN THE ANALYSIS OF VARIANCE OF A FACTORIAL EXPERIMENT
Authors: Ashton G. C. , Rennie J. C. , Etter E.
Published: March 2010

Frequently imposed experimental treatments in biological research produce results which require evaluation in terms of interdependence between the factors under study. Data from a 2-factor calf-feeding experiment have been used to illustrate the inadequacy of over-all means in describing the treatment effects where factor interdependence existed. It was shown that, to make accurate appraisal of the treatment effects under these conditions, it is necessary to restrict consideration to the subtreatment means.
THE ESTROGEN-LIKE SUBSTANCES IN CERTAIN LEGUMES AND GRASSES: I. THE QUANTITATIVE DETERMINATION OF SUCH SUBSTANCES IN RED CLOVER AND OATS
Authors: Kitts W. D. , Wood A. J. , Swierstra E. , Brink V. C.
Published: March 2010

A 3-day per orum procedure, using female mice 20–21 days old and weighing 8–12 gm., was evolved for the determination of the estrogen-like substances in forage. With diethylstilbestrol (D.E.S.) as reference compound a dose response curve was constructed. From this curve the estrogenic activity of plant material was estimated and expressed in terms of D.E.S. Studies were undertaken to determine the effects of stage of maturity and frequency of cutting of first- and second-year growth of red clover and first-year growth of Victory oats. The samples from first- and second-year growth of red clover possessed considerable estrogenic activity. The level of activity was highest in the spring and decreased towards the autumn. Victory oats possessed little or no estrogenic activity at any time during the growing season.
THE PROTEIN REQUIREMENTS OF LAYING HENS IN FLOOR PENS AND INDIVIDUAL CAGES
Authors: MacIntyre T. M. , Aitken J. R.
Published: March 2010

Diets varying in protein content from 10.9 to 16.7 per cent were fed over a 336-day laying period to hens in both floor pens and individual laying cages. All rations were approximately iso-caloric, the mean productive energy value being 825 Calories per pound. Each ration was fed to 200–240 hens in four floor pens and to 90–96 hens in individual cages.A crude protein level of 13 per cent of the diet proved adequate for egg production, but egg weights and body weights were improved when the dietary protein was increased. Egg shell quality was highest on low protein diets. Interior egg quality was not affected by the protein level in the diet.On comparable diets, birds in individual laying cages laid fewer eggs and consumed less feed than birds in floor pens. Caged birds were heavier in body weight and laid heavier eggs with thicker shells than their counterparts in floor pens. The criteria employed in the measurement of interior egg quality showed no differences between the cage and pen environments, nor did there appear to be any differences in protein requirements between the two environments.
EFFECT OF ESTRADIOL AND TESTOSTERONE INJECTIONS AND THYROIDECTOMY ON WOOL GROWTH IN SHEARLING SHEEP
Authors: Slen S. B. , Connell R.
Published: March 2010

An experiment was conducted to determine the effect of relatively high doses of estradiol and testosterone, with and without thyroidectomy, on clean wool production and certain endocrine glands of shearling sheep. The administration of 5 milligrams of estradiol intramuscularly at biweekly intervals to sheep with thyroids caused a reduction in the average weight of clean wool (p <.05) and fibre length (p <.01). This treatment produced increases (p <.01) in thyroid, pituitary, and adrenal weights. The administration of estradiol to thyroidectomized ewes reduced the weight of clean wool (p < 05) when compared with the thyroidectomized controls but no such response was observed in wethers. Testosterone administered at levels of 175 milligrams bi-weekly produced no effect on weights of clean wool, in ewes or wethers, but when it was administered to thyroidectomized animals average fibre lengths were decreased (p <.05).
THE EFFECT OF FINE GRINDING OF HAY ON RATION DIGESTIBILITY, RATE OF PASSAGE, AND FAT CONTENT OF MILK
Authors: Rodrigue C. B. , Aixen N. N.
Published: March 2010

Three series of digestion trials, involving a total of 20 lactating cows, were conducted to compare the digestibility and rate of passage of hay ground to various degrees of fineness, with that of unground hay.Grinding the hay in a ration composed of two parts hay and one part concentrate by weight produced an earlier initial excretion of hay residues in all cows. Excretion of finely ground hay was also more rapid than unground hay throughout the period. The change in excretion time due to grinding was statistically significant.The most marked effect on digestibility was the highly significant decline (P < 0.01) in digestibility of fibre and/or cellulose as a result of grinding hay. This was mainly responsible for the highly significant decrease (P < 0.01) in dry matter digestion. Grinding also significantly lowered (P < 0.05) the digestibility of ether extract in trials of series II and of protein and N.F.E. in trials of series III.A relationship was established between rate of passage of hay and digestibility of the total ration. The finer the hay was ground, the greater was the depression in digestibility of the total ration and the faster the rate of excretion. The large depression in the digestibility of the cell wall constituents was associated with a marked decrease in milk fat percentage.
INGREDIENT AND PROCESSING INTERRELATIONSHIPS IN SWINE FEEDS: II. EFFECTS OF ANTIBIOTICS, PROTEIN SOURCE AND PELLETING ON THE RESPONSES TO THE INCLUSION OF WHEAT BRAN
Authors: Gorrill A. D. L. , Bell J. M. , Williams C. M.
Published: March 2010

This is the second in a series of reports on the growth, feed intake and digestibility responses of growing swine (50 to 110 pounds) involved in a 2 × 2 × 2 × 2 factorial test of the effects of wheat bran, pelleting, antibiotics and type of protein in the ration. Discussion in this paper was restricted to those factors affecting the responses to the inclusion of wheat bran.With approximately isocaloric diets the inclusion of 10 per cent bran resulted in a general increase of 6 per cent in feed intake (P = <.01) and 8 per cent in digestibility of protein. The greatest effects were obtained with antibiotic-free, animal protein-free, meal-type rations in which the inclusion of bran resulted in 18 per cent more feed and 28 per cent more digestible energy being consumed.The effect of bran on energy digestibility was small relative to its effect on protein. It is postulated that differences in the rates and site of absorption of starch and protein components may be related to the efficacy of bran in the digestive tract.The similarity observed between the effects of bran and antibiotics is discussed in relation to possible deficiencies of B-vitamins and amino acids.
THE FEEDING OF RYE TO GROWING CHICKENS
Authors: Smith R. E. , MacIntyre T. M.
Published: March 2010

Four experiments were carried out with growing chickens to study the feeding value of rations containing rye. Levels of rye in the rations ranged from 0 to 60 per cent. The criteria employed to evaluate this effect were body gain, feed efficiency, and carcass grade.All-mash rations containing rye resulted in poorer growth and feed efficiency than similar rations containing wheat. Pelleting was found to improve the feeding value of rye by the chicken. Pelleted rations containing rye gave growth and feed efficiency equivalent to that obtained on all-mash rations containing wheat. Increasing levels of rye from 15 to 60 per cent in pelleted rations had no significant effect on weight gains but each increment of rye resulted in a noticeable (but non-significant) loss in feed efficiency.
ESTIMATING BREEDING VALUES OF DAIRY BULLS FROM CANADIAN R.O.P. RECORDS
Authors: Hickman C. G.
Published: March 2010

A random assortment of mates is implicit in published methods for estimating breeding value of dairy sires, based on daughter-dam or daughter-contemporary comparisons. A combination of the two methods, based on first lactation records of dams and daughters and of their own contemporaries, is proposed and will be tested when sufficient data are available. A method based on a maximum likelihood estimate of contemporaries was used to analyse data available from Canadian Record of Performance for four breeds with an estimated 40 to 470 testable bulls bi-annually. Some 50 per cent of the herds were considered too small to provide suitable records. Breeding values of sires were over- or underestimated from simple averages of progeny and this bias was reduced by using contemporaries. The handicap to younger sires, resulting from the correlation between contemporary comparisons and average age of progeny groups, can be avoided by making the comparisons within age groups.
AN APPRAISAL OF RUELENE AND TROLENE AGAINST CATTLE GRUB INFESTATIONS, (OESTRIDAE: DIPTERA)
Authors: Rich G. B. , Ireland H. R.
Published: March 2010

The reductions in numbers of cattle warble grubs produced by Ruelene and Trolene in a heavily infested cattle herd were compared. Ruelene intramuscular injections at 5 mg./kg. and 10 mg./kg. and Trolene boluses at 105 mg./kg. reduced the numbers of grubs by 83, 86 and 86 per cent, respectively. Statistically these reductions were not significantly different. The intramuscular injections did not cause detectable lesions at the injection site in the 90 calves treated. The injection method was preferred to the bolus method for ease of administration, economy of labour, and decreased danger of injury to animals. Feeding Ruelene at 5 mg./kg. and 10 mg./kg. daily for 5 days, and feeding Trolene at 15 mg./kg. daily for 7 and 12 days, reduced the numbers of grubs by 95, 94, 94 and 97 per cent respectively. These reductions were not significantly different.
THE EFFECT OF A PURIFIED SOURCE OF CELLULOSE ON THE GROWTH AND BODY COMPOSITION OF GROWING PIGS
Authors: Cunningham H. M. , Friend D. W. , Nicholson J. W. G.
Published: March 2010

One hundred pigs were used in two experiments to determine the nutritive value of a purified source of cellulose (solka-floc) and its effect on body composition and iodine number of the loin fat. In each experiment one group of pigs received a basal ration ad libitum while levels of 10 and 40 per cent solka floe were added to the basal ration of two groups at 62 and 162 pounds liveweight, respectively. The pigs given solka-floc were fed ad libitum and the amounts of basal ration consumed were pair-fed to two respective control groups. There was a significant decrease (P <.01) in dressing percentage of pigs fed solka-floc. Feed efficiency, based on total feed (less solka-floc) per pound of gain, was better in the pair-fed controls reaching statistical significance (P <.05) in one experiment. There was no significant difference in the protein or fat content of the carcasses but the iodine number of the loin fat was significantly higher (P <.01) in pigs fed solka-floc. It was concluded that in growing pigs there is no net gain in energy from the consumption of cellulose.
THE ADDITION OF BUFFERS TO RUMINANT RATIONS: I. EFFECT ON WEIGHT GAINS, EFFICIENCY OF GAINS AND CONSUMPTION OF RATIONS WITH AND WITHOUT ROUGHAGE
Authors: Nicholson J. W. G. , Cunningham H. M.
Published: March 2010

A total of sixty-eight beef steers were used in three feeding trials to determine the effects of adding buffers to ruminant rations. The buffers used in these trials were sodium propionate and mixtures of sodium bicarbonate, potassium carbonate and calcium carbonate (as ground limestone). They were fed at levels varying from 2 to 9 pounds per 100 pounds of the concentrate ration. Data on feed consumption, weight gains and efficiency of feed conversion are presented.The addition of buffers to a ration containing timothy hay fed ad libitum did not prove beneficial. Buffers at the highest level (9 pounds per 100 pounds) were detrimental in the hay-concentrate ration. When the hay was removed from the ration there were highly significant decreases in weight gains and T.D.N. consumption. These decreases were partially offset by the addition of buffers to the all-concentrate rations. The results may have a practical application in the feeding of low-roughage rations.
NOTE ON A SIMPLE MACHINE FOR MINCING LARGE CARCASSES
Authors: Cunningham H. M. , Gray I. , Johnson E. C. A.
Published: March 2010

not available
AN APPRAISAL OF CERTAIN SOURCES OF ENVIRONMENTAL VARIATION IN THE PRODUCTIVITY OF YORKSHIRE SOWS
Authors: Bowman G. H. , Bowland J. P. , Fredeen H. T.
Published: March 2010

Analysis of the records of 616 Yorkshire litters farrowed over a 20-year period in the University of Alberta swine herd indicated that litter performance was not associated with differences in weight changes of the sow during gestation or with gestation length. Gestation weight change was negatively correlated with breeding weight and lactation weight changes. Age of sow, breeding weight and litter order were highly correlated and were mutually dependent in their effect on litter performance. Least squares estimates of year, season, breeding weight of sow, and weight change during lactation effects were obtained for several performance traits of the litter. Year differences were large but erratic for all traits. Seasonal differences appeared to be important only for litter size with fall litters averaging 0.78 more pigs at weaning than spring litters. Weight of sow at breeding exerted an important influence on litter performance. Weight change during lactation appeared to be a function of litter size.Study of the relative influence of age and weight of gilts at breeding on first litter size at birth and weaning indicated that breeding weight exerted the greater influence.It is concluded that comparisons between litters in the same herd and born within the same year and season must provide for statistical control of variation in weight of dam at breeding. If inter-year comparisons are desired additional statistical control is essential.
NOTE ON GRASS SILAGE IN RATIONS FOR WINTERING BEEF CALVES
Authors: Jordan W. A. , Sylvestre P. E.
Published: March 2010

not available