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Posttranslational modifications, mostly phosphorylation, are critical for protein structure and function. However, the association between liver phosphoproteins in neonatal calves and colostrum intake is not well understood. In this study, we examined the liver phosphoproteome profile in neonatal calves after receiving colostrum or milk. Liver tissue samples were collected from control calves (CON, n = 3) 2 h after birth and from calves that received colostrum (CG, n = 3) or milk (MG, n = 3) 24 h after birth. Hepatic phosphoprotein expression profiles were analyzed using quantitative proteomics based on the liquid chromatography-tandem mass spectrometry method. In total, 1,587 phosphorylated sites were identified in 1,011 liver proteins. The most abundant phosphorylation site AA was serine (87.5%), followed by threonine (11.9%) and tyrosine (0.5%). Among the 1,011 phosphoproteins, 219, 453, and 26 displayed differential expression in the CG versus MG, CG versus CON, and MG versus CON comparisons, respectively. Differentially expressed phosphoproteins in the CG-MG comparison included 3-phosphoinositide-dependent protein kinase 1, glucose transporter member 4, protein kinase N2, and vinculin, which were mainly involved in the glycogen metabolic process, transport, growth and development, and cell adhesion process, according to Gene Ontology analysis. Pathway analysis indicated their enrichment in the insulin signaling pathway, spliceosome, and adherens junction. The CG-CON comparison identified differentially expressed phosphoproteins and their target genes that were largely involved in the cellular process, macromolecule metabolic process, developmental process, and transport. Pathway analysis indicated their association with endocytosis, mechanistic target of rapamycin, AMP-activated protein kinase, and insulin signaling pathways. These data demonstrate that changes in the phosphoproteins of liver tissues may play an important role in energy metabolism and immune response in the calves that received colostrum. These results provide novel insights into the crucial roles of protein phosphorylation during the early life of newborn calves.

The contribution of intestinally absorbed colostral immunoglobulins to the transmission of passive immunity is widely reported in neonatal calves. However, changes in the colostral proteome in the gastrointestinal digesta remain unclear. Therefore, this study aimed to investigate changes in colostral proteome affected by gastrointestinal proteases in neonatal calves. Twenty-one neonatal Holstein calves were used in this study, including 18 colostrum-fed calves slaughtered at 8 (CI, n = 6), 24 (CII, n = 6), and 36 h (CIII, n = 6) postpartum and 3 milk-fed calves slaughtered 24 h postpartum (MI, n = 3). The ingested colostrum and milk samples were collected from the mid-jejunum segment, following the sacrifice. The undigested colostrum or milk along with their ingested colostrum or milk samples were investigated using a label-free proteomics approach. Hierarchical clustering and principal component analysis of the quantified proteins revealed that the ingested colostrum from the CII and CIII groups and the ingested mature milk from the MI group appeared to share similar patterns. Analysis of the intestinal digesta revealed a time-dependent decrease in caseins, lactoferrin, and osteopontin protein levels, and an increase in cationic trypsin, chymotrypsin, and carboxypeptidase. Several protease inhibitors, such as α-1-antiproteinase, α-2-antiplasmin, and early lactation protein, were identified in the colostrum and intestinal digesta. In addition, we detected identical levels in the intestinal digesta and colostrum for albumin, α-1-acid glycoprotein, and plasminogen. Pathway analysis indicated that proteins increased in the intestinal digesta belonged to the following categories: biosynthesis of antibiotics, carbon metabolism, and biosynthesis of amino acids. These results indicated that selected colostral proteins were digested by gastrointestinal proteases, contributing to their intestinal absorption in calves. These findings provide new insights into the fate of the colostral proteome in the gastrointestinal tract and may aid in the identification of factors contributing to health management in neonatal calves.

The newborn gut undergoes rapid colonization by commensal microorganisms and possible exposure to pathogens. The contribution of colostrum intake to host protection is well known; however, limited research exists on the intestinal innate immunity corresponding to colostrum intake during the passive immune transfer period in newborn ruminants. The aim of this study was to investigate the changes in bacterial community and expression of genes encoding toll-like receptors (TLR), mucins (MUC), antimicrobial peptides, and tight junctions in the jejunum of lambs that were fed colostrum during the first 24 h of life. Twenty-seven newborn lambs were used in this study, of which 18 lambs were bottle-fed pooled bovine colostrum within the first 2 h after birth to obtain an intake of approximately 8% of body weight. Lambs were slaughtered at 12 (n = 9) and 24 h (n = 9) after birth. The remaining 9 lambs without any feeding were slaughtered at 30 min after birth (0 h). Tissue and ligated segment samples from the jejunum were collected immediately after the lambs were slaughtered. The bacterial profile in the ligated jejunum segment was assessed using amplicon sequencing. The gene expression in the jejunum tissue was determined using quantitative real-time PCR. The relative abundances of Escherichia-Shigella, Lactobacillus, Lactococcus, and Streptococcus increased, whereas those of Sphingomonas, Phyllobacterium, Bradyrhizobium, and Rudaea decreased during the first 24 h of life. Expression of TLR2 and β-defensin 109-like was upregulated at 12 h after birth, but a recovery was detected at 24 h; TLR3, TLR5, LYZ, MUC1, MUC13, MUC20, and CLDN7 showed a higher expression level in samples taken at 24 h than in those taken at 0 h. In addition, expression level of CLDN1, CLDN4, and the junctional adhesion molecule-1 tended to be higher at 24 h than at 0 h after birth. Correlation analysis indicated that TLR2 expression was negatively correlated with the relative abundance of Lactobacillus and Bradyrhizobium, whereas TLR5 expression was positively correlated with the relative abundance of Escherichia-Shigella and Pelagibacterium. These results suggest that TLR, MUC, antimicrobial peptides, and CLDN act together and play an important role in intestinal defense during the passive immune transfer period. They are potentially associated with microbial colonization. The findings from this study provide novel information to elucidate the role of colostrum components in regulating the development of the intestinal mucosal immune barrier in newborn lambs during the passive immune transfer period.

Colostrum is a unique resource that contributes to the passive transfer of immunity and plays a central role in the health status of neonatal ruminants. However, digestion and absorption of colostral proteins in the gut remain incompletely understood. Therefore, this study aimed to investigate the effect of bovine colostrum feeding on blood metabolic traits and to quantify colostral bioactive proteins in the gastrointestinal digesta and blood to evaluate intestinal transfer in neonatal lambs in the first 24 h of life. Fifty-four newborn lambs were used in this study, including 27 lambs fed pooled bovine colostrum and slaughtered at 6 (C6h), 12 (C12h), or 24 h (C24h) after birth; 18 lambs not fed any colostrum or milk and slaughtered at birth (N0h) or 24 h (N24h) after birth; and 9 milk-fed lambs slaughtered at 24 h (M24h) after birth. Lambs receiving colostrum or milk were bottle-fed within the first 2 h to obtain intakes of 8% of body weight at birth. Samples of blood and digesta from the abomasum, jejunum, and ileum were collected after slaughter. Serum concentrations of glucose, insulin, total protein, and aspartate aminotransferase were higher in colostrum-fed lambs than in N0h lambs. Serum concentrations of insulin, total protein, insulin-like growth factor 1, and γ-glutamyl transpeptidase were higher in C24h lambs than in N24h or M24h lambs. Apparent efficiencies of IgG absorption in C6h, C12h, and C24h lambs were 14.4, 26.8, and 17.2%, respectively, whereas apparent efficiencies of lactoferrin (LF), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG) absorption were very low in colostrum-fed lambs, with mean values of 0.06, 0.002, and 0.003%, respectively. Concentrations of IgG, LF, α-LA, and β-LG in the digesta of the abomasum, jejunum, and ileum rapidly decreased from C6h to C24h lambs, and the disappearance rates of IgG, LF, α-LA, and β-LG were higher in lambs from C6h to C12h (62.1, 75.7, 91.3, and 95.0% for IgG, LF, α-LA, and β-LG, respectively) than from C12h to C24h (34.6, 22.5, 7.5, and 2.2% for IgG, LF, α-LA, and β-LG, respectively). These results indicated that bovine colostrum feeding improved the metabolic and immunological status of lambs, and that ingested colostral IgG was prone to intact uptake into the blood, whereas almost all ingested LF, α-LA, and β-LG disappeared in the lumen of the gastrointestinal tract in a time-dependent manner. The findings provide novel information for exploring selective absorption of colostral compounds in the small intestine of lambs.

The contribution of colostrum to passive immunity transfer and intestinal protection is well known; however, the effects of colostrum intake on the expression of antimicrobial peptides (AP) and Fc receptors in the intestine of neonatal calves are unclear. Our aim was to investigate changes in the expression of AP and Fc receptor in the small intestine of calves in the first 36 h postpartum. Twenty-four Holstein bull calves were used in this study, of which 18 calves were administered 3.2 L of pooled colostrum for each calf per meal via an esophageal tube. Calves were slaughtered at 8 h (1 meal at 1-2 h), 24 h (2 meals at 1-2 h and 10-12 h), and 36 h (3 meals at 1-2 h, 10-12 h, and 22-24 h) postpartum. The remaining 6 calves without any milk administration were slaughtered at 2 h postpartum. Samples of blood and jejunum digesta were collected to determine immunoglobulin concentration using ELISA. Samples of the duodenum, jejunum, and ileum tissues after slaughter were collected to determine AP and Fc receptor expression using quantitative real-time PCR. In calves administered colostrum, IgG concentration in jejunum digesta rapidly decreased in an age-dependent manner (33.41, 9.47, and 0.34 mg/mL at 8, 24, and 36 h, respectively), whereas serum IgG concentration increased significantly, from 0.25 μg/mL at 2 h to 21.72 mg/mL at 24 h. Cathelicidin-4, β-defensin (DEFB)-7, and enteric β-defensin expression was upregulated at 8 h postpartum in the duodenum and jejunum compared with that at 2 h, but progressive recovery was detected from 24 h onward. Higher expression of cathelicidin-4, regenerating family member 3γ, lysozyme (LYZ), LYZ1, and LYZ2 and lower expression of DEFB, DEFB1, DEFB7, DEFB10, and enteric β-defensin were observed in the duodenum and jejunum compared with the ileum. Differences in AP expression between intestinal regions suggested that the innate immune defense mechanism varied significantly among the duodenum, jejunum, and ileum. No difference in the expression of Fc fragment of the IgG receptor was observed either among ages or small intestinal regions. The Fcγ receptor (FcγR)Ia and FcγRIIb expression was the highest at 8 h compared with that at 2, 24, and 36 h, and expression of FcγRIa, FcγRIIb, and FcγRIIIa was higher in the duodenum and jejunum than in the ileum. These results indicated that AP and Fcγ receptors might play important roles in intestinal defense during the passive immunity period.

Uptake of colostrum is of central importance for establishing a passive immunity transfer in neonatal calves. Studies of absorption and transmission of colostral immunoglobulins have been widely reported; however, changes in the serum in response to the absorption of colostral components in neonatal calves have not been completely characterized. Here, a nuclear magnetic resonance-based metabolomics approach was used to investigate the changes in metabolites in ingested colostrum, milk, and serum after neonatal calves were fed colostrum or milk. Twenty-seven neonatal male Holstein calves were assigned to 1 of the following groups: (1) calves not fed colostrum or milk and slaughtered approximately 2 h after birth (control group, n = 6), (2) calves fed colostrum at 1 to 2 h after birth and slaughtered 8 h after birth (n = 6), (3) calves fed 2 colostrum meals (at 1-2 and 10-12 h after birth) and slaughtered 24 h after birth (n = 6), (4) calves fed 3 colostrum meals (at 1-2, 10-12, and 22-24 h after birth) and slaughtered 36 h after birth (n = 6), or (5) calves fed 2 milk meals (1-2 and 10-12 h after birth) and slaughtered 24 h after birth (n = 3). Concentrations of valine, leucine, lactate, lysine, and isoleucine were higher and concentrations of lactose were lower in the groups fed colostrum and milk compared with groups not fed colostrum and milk, respectively. Metabolite changes between groups fed or not fed colostrum and milk were similar and may reflect the primary metabolic requirements of ingestion by the small intestine of neonatal calves. Concentrations of serum metabolites choline, valine, leucine, and glutamate were higher in the serum of calves that received colostrum compared with control calves. Furthermore, concentrations of serum phenylalanine, valine, and glutamate were significantly higher, whereas serum concentrations of citrate and very low density lipoproteins were lower in calves that received colostrum compared with calves fed milk. Our results indicate that concentrations of leucine, valine, and glutamate, which were higher in the calves that ingested colostrum, may transfer into the bloodstream, and that these metabolites are associated with health benefits in the neonatal calves that received colostrum. These findings provide novel information to help us understand the mechanism by which colostrum components are metabolized and absorbed in the small intestine and then transferred into bloodstream of neonatal calves.

A high spectra resolution X-ray imaging crystal spectrometer has been implemented on J-TEXT Tokamak for the measurements of Kα spectra of helium-like argon and its satellite lines. The wavelength range of Kα spectra of helium-like argon is from 3.9494 A to 3.9944 A that includes the resonance line w, intercombination lines x and y, forbidden line z and numerous satellite lines, referenced using standard Gabriel notation. In low-density discharge, the intensity of q, r satellite lines and z lines can be significantly enhanced by non-thermal electrons. Non-thermal electrons are produced due to the low plasma density. The high hard X-ray flux from NaI detector and significant downshift electron cyclotron emissions from energetic runaway electrons also indicated that there is a large population of runaway electrons in the low-density discharge. The non-thermal part of electrons can affect the excitation/transition equilibrium or ionization/recombination equilibrium. The q line is mainly produced by inner-shell excitation of lithium-like argon, and the r line is partially produced by inner-shell excitation of lithium-like argon and dielectronic recombination of helium-like argon.

An x-ray imaging crystal spectrometer has been developed on joint Texas experimental tokamak for the measurement of electron and ion temperatures from the Kα spectra of helium-like argon and its satellite lines. A two-dimensional multi-wire proportional counter has been applied to detect the spectra. The electron and ion temperatures have been obtained from the Voigt fitting with the spectra of helium-like argon ions. The profiles of electron and ion temperatures show the dependence on electron density in ohmic plasmas.

Ballistic tests are performed by shooting both tungsten fiber/bulk metallic glass W/Zr58Ti13Cu17Ni12 composite rods (composite rod) and tungsten heavy alloy rods (95W rod) into 30CrMnMo target. The composite rod exhibits self-sharpening behaviors, and its matrix damages and fibers break are limited in a thin, narrow area, which is defined as "edge layer". Penetrating depth of composite rods is 50% deeper than the depth of 95W rods with same dimension size. (C) 2012 Elsevier Ltd. All rights reserved.

A DNA fragment (4262 bp) of sheep GPR54 gene was obtained through PCR and DNA sequencing methods. One nucleotide transition mutation (A125G) and one 5 bp deletion/insertion (TTCTT) mutation at the 163–167 locus in 5´-regulatory region of sheep GPR54 gene were identified by sequence alignment between Small Tail Han and Corriedale sheep. The distributions of these two mutations were determined in high prolificacy breeds (Small Tail Han and Hu sheep) and low prolificacy breeds (Chinese Merino and Corriedale sheep) and their effects on litter size in Small Tail Han sheep were also evaluated. The results showed that the two mutations existed in all four sheep breeds tested. In Small Tail Han sheep, genotype frequency of AA, AG and GG was 0.250, 0.500 and 0.250, respectively. The differences of litter size between three genotypes were not significant in Small Tail Han sheep (P > 0.05). Genotype frequency of CC, CD and DD was 0.175, 0.125 and 0.700, respectively. Small Tail Han sheep ewes with genotype CC had 0.66 (P

Shear failure and deformation localization are studied for tungsten alloy undergoing impact failure and “self-sharpening” in ordnance. Movable cellular Automata (MCA) method is employed to simulate the interior-structure of tungsten alloy such that shear deformation failure at mesoscale level under shear loading can be analyzed. The results show that the velocity of every automaton would vary continuously with deformation. A large velocity vortex sweeping throughout the specimen occurs at the initial loading stage. This corresponds to uniform deformation. Subsequently, the deformation adopts a pattern with more localized vortices. The vortex-morphology would change continually to sustain the global deformation field. The contact between the local vortices induces stress concentration. This means that the deformation of certain automaton pairs would not accommodate the equilibrium of vortex rotation. The different mechanisms of micro-damage mechanisms along the interface between the W grain and matrix are developed quickly throughout the whole specimen. Such shear instability leads to failure. It is also shown that the W grain size effect is sufficient to cause premature shear deformation instability of the tungsten alloy, even at low shear stress.

Movable Cellular Automata (MCA) is a new efficient numerical method in particle mechanics that is different from methods in the traditional continuum mechanics. In this paper MCA is applied to addressing buckling and post-buckling problems in solid mechanics. The simulation of the buckling behavior of a column subjected to a quasi-static loading is presented in this article. The critical buckling loads result obtained by MCA is consistent with the values calculated by the classical mechanics of materials. Under the post-buckling of the column, a lateral vibration of the column is observed, which was considered to be impossible at so low strain rate of e ˙ = 10 - 3 . The equilibrium positions of the vibration of the column are continually adjusted to match the curves of deflection of post-buckling. The vibration decays quickly with the buckling deflection increasing. Finally, the deflections of post-buckling increase steadily and the capability of bearing load of the column is slowly reduced.

A systematic study of disruption-generated runaway electrons has been performed in the J-TEXT tokamak. During the intended disruption by the argon injection in J-TEXT, the runaway electron plateau is more easily obtained with a higher loop voltage and shorter onset time of high loop voltage. Magnetic fluctuations are observed at the beginning of the current quench during the disruptions. The generated runaway electron (RE) current is larger at a lower level of magnetic fluctuation. Experimental evidence supporting that the theory of hot tail RE generation might be playing a role has also been found. With higher temperature before the disruption, more REs are generated via the hot tail mechanism during the thermal quench. By increasing the hot tail RE generation by increasing the temperature, an obvious RE plateau is observed even with a low toroidal magnetic field (1.2 T).

When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

The topology of a magnetic field and transport properties of runaway electrons can be changed by a resonant magnetic perturbation field. The J-TEXT magnetic topology can be effectively altered via static resonant magnetic perturbation (SRMP) and dynamic resonant magnetic perturbation (DRMP). This paper studies the effect of resonant magnetic perturbation (RMP) on the confinement of runaway electrons via simulating their drift orbits in the magnetic perturbation field and calculating the orbit losses for different runaway initial energies and different runaway electrons, initial locations. The model adopted is based on Hamiltonian guiding center equations for runaway electrons, and the J-TEXT magnetic turbulences and RMP are taken into account. The simulation indicates that the loss rate of runaway electrons is sensitive to the radial position of electrons. The loss of energetic runaway beam is dominated by the shrinkage of the confinement region. Outside the shrinkage region of the runaway electrons are lost rapidly. Inside the shrinkage region the runaway beam is confined very well and is less sensitive to the magnetic perturbation. The experimental result on the response of runaway transport to the application RMP indicates that the loss of runaway electrons is dominated by the shrinkage of the confinement region, other than the external magnetic perturbation.

The measurement of internal magnetic fluctuation is important for the study of transport in tokamak plasmas. The runaway electron transport induced by the sawtooth crash can be used to obtain the internal magnetic fluctuation. Inversed sawtooth-like activities on hard x-ray (HXR) fluxes following sawtooth activities were observed after the application of electrode biasing on J-TEXT tokamak. The runaway diffusion coefficient Dr is deduced to be about 30 m2/s according to the time delay of HXR flux peaks to the sawtooth crashes. The averaged value of normalized magnetic fluctuation in the discharges with electrode biasing was increased to the order of 1 × 10−4.

Runaway currents following disruptions have an important effect on the first wall in current tokamaks and will be more severe in next generation tokamaks. The behavior of runaway currents in massive gas injection (MGI) induced disruptions have been investigated in the J-TEXT tokamak. The cold front induced by the gas jet penetrates helically along field lines, preferentially toward the high field side and stops at a location near the q = 2 surface before the disruption. When the cold front reaches the q = 2 surface it initiates magnetohydrodynamic activities and results in disruption. It is found that the MGI of He or Ne results in runaway free shutdown in a large range of gas injections. Mixture injection of He and Ar (90% He and 10%Ar) consistently results in runaway free shutdown. A moderate amount of Ar injection could produce significant runaway current. The maximum runaway energy in the runaway plateau is estimated using a simplified model which neglects the drag forces and other energy loss mechanisms. The maximum runaway energy increases with decreasing runaway current. Imaging of the runaway beam using a soft x-ray array during the runaway current plateau indicates that the runaway beam is located in the center of the plasma. Resonant magnetic perturbation (RMP) is applied to reduce the runaway current successfully during the disruption phase in a small scale tokamak, J-TEXT. When the runaway current builds up, the application of RMP cannot decouple the runaway beam due to the lower sensitivity of the energetic runaway electrons to the magnetic perturbation.

The suppression of runaways following disruptions is key for the safe operation of ITER. The massive gas injection (MGI) has been developed to mitigate heat loads, electromagnetic forces and runaway electrons (REs) during disruptions. However, MGI may not completely prevent the generation of REs during disruptions on ITER. Resonant magnetic perturbation (RMP) has been applied to suppress runaway generation during disruptions on several machines. It was found that strong RMP results in the enhancement of runaway production instead of runaway suppression on J-TEXT. The runaway current was about 50% pre-disruption plasma current in argon induced reference disruptions. With moderate RMP, the runway current decreased to below 30% pre-disruption plasma current. The runaway current plateaus reach 80% of the pre-disruptive current when strong RMP was applied. Strong RMP may induce large size magnetic islands that could confine more runaway seed during disruptions. This has important implications for runaway suppression on large machines.

Disruption mitigation is essential for the next generation of tokamaks. The prediction of plasma disruption is the key to disruption mitigation. A neural network combining eight input signals has been developed to predict the density limit disruptions on the J-TEXT tokamak. An optimized training method has been proposed which has improved the prediction performance. The network obtained has been tested on 64 disruption shots and 205 non-disruption shots. A successful alarm rate of 82.8% with a false alarm rate of 12.3% can be achieved at 4.8 ms prior to the current spike of the disruption. It indicates that more physical parameters than the current physical scaling should be considered for predicting the density limit. It was also found that the critical density for disruption can be predicted several tens of milliseconds in advance in most cases. Furthermore, if the network is used for real-time density feedback control, more than 95% of the density limit disruptions can be avoided by setting a proper threshold.

This paper presents a new GPS slot antenna consisting of six quarter-wavelength resonant slots. Each of the six resonant slots is rolled a half-turn around the cylindrical laminate and maintains constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. The printed cylindrical slot antenna presented is useful in applications where low-profile installation is required on a highly dynamic aircraft. This new printed GPS antenna provides compact size, low cost, ease of mass production, near-hemispherical radiation coverage and circular polarization properties. Experimental results show that the new hexafilar antennas have a 3 dB beamwidth of more than 120/spl deg/ and a front-back ratio of more than 15 dB.

This paper presents a new GPS quadrifilar slot antenna consisting of four quarter-wavelength crank slots. The four resonant crank slots are equally placed around the circumference of a cylindrical laminate and they maintain a constant phase relation to each other to form a right-hand circular polarization to receive GPS satellite signals. This new resonant helical slot antenna has a beamwidth of more than 120 degrees and a null at the back, which means an excellent capability for receiving low-elevation satellite signals and rejecting multipath interference.

Azobenzene-containing glassy nematic sheets deform in response to light in a complicated way depending on director distribution. To quantify the large-deflected deformation, a theoretical model is developed for the sheets with typical splay-bend and twist director distributions. A third-order in-plane displacement assumption is adopted to characterize the effect of transverse shear deformation, and the necessity is discussed through two examples for which analytical solutions are obtainable. Though this work is an extension of the third-order shear deformable theory for anisotropic laminates, it involves some new ingredients such as varying spontaneous strains and special material symmetries. The results are expected useful for analysis and design of the glassy nematic sheets in actuation applications.

A modified continuum model of elastic films with nano-scale thickness is proposed by incorporating surface elasticity into the conventional nonlinear Von Karman plate theory. By using Hamilton’s principle, the governing equations and boundary conditions of the ultra-thin film including surface effects are derived within the Kirchhoff’s assumption, where the effects of non-zero normal stress and large deflection are taken into account simultaneously. The present model is then applied to studying the bending, buckling and free vibration of simply supported micro/nano-scale thin films in-plane strains and explicit exact solutions can be obtained for these three cases. The size-dependent mechanical behavior of the thin film due to surface effects is well elucidated in the obtained solutions.

Abstract Foam stability in the presence of Salem crude oil and pure hydrocarbons is investigated as a function of pure hydrocarbons is investigated as a function of chain length of -olefin sulfonates and electrolyte concentration. Interactions between aqueous foam films and emulsified oil droplets are observed using transmitted light, incident light interferometric and differential interferometric microscopic techniques. Foam destabilization factors are identified including the pseudoemulsion film tension and the surface and interfacial tension gradients. Results from foam-enhanced oil recovery experiments in Berea Sandstone cores are presented using the combined gamma ray/microwave absorption technique to measure dynamic fluid saturation profiles. Introduction Three phase foam stability, as has been discussed by numerous authors is of great practical significance. However, despite the recognized significance, the mechanisms by which oil affects foam stability are still under investigation. The effect of oil upon foam stability has been explained in rather general terms through the mechanism of oil spreading phenomena, but the reason why the oil droplets spread and the film between the oil droplets and air bubbles breaks has not been discussed. Our objective in this study is to classify the complex phenomena occurring during the process of three phase foam thinning, to identify the interaction mechanisms between the oil droplets, the thinning foam film and the Plateau-Gibbs borders and the role of surface and interfacial tension gradients in foam stability, and to examine the implications upon crude oil displacement by foam in porous media. During the process of three phase foam thinning, three distinct films may occur: foam films (water film between air bubbles), emulsion films (water between oil droplets) and pseudoemulsion films (water film between air and oil droplets) (Figure 1). To study the behavior of these films and particularly the oil droplet-droplet, oil particularly the oil droplet-droplet, oil droplet-air bubble and oil droplet-foam frame interactions it is necessary to utilize numerous microscopic techniques, including transmitted light, microinterferometric, differential interferometric and cinemicrographic microscopy. EXPERIMENTAL Surfactant-Oil-Electrolyte Systems In this study we used as surfactants alpha-olefin sulfonates C12, C14 and C16 (anionic surfactants, product of Ethyl Corp.) and Enordet AE 1215-30 product of Ethyl Corp.) and Enordet AE 1215-30 (nonionic surfactant, product of Shell Development Co.). For all measurements, the surfactant concentration was chosen at 3.16 × 10(-2) mol/1, several times above the critical micelle concentration (cmc). These particular surfactants (and concentrations) were chosen on the basis of industrial applications. As oil phases we used n-octane (Fisher Sci. Co. reagent grade Lot 746833 class IB) and n-dodecane (Fisher Sci. Co. purified grade Lot 852154), both chosen for their well-defined structure and Salem crude oil, chosen for its practical value. Electrolyte was chosen as NaCl, at two concentrations 0.17 mol/1 (1 wt%) and 0.51 mol/1 (3 wt%). In each study the oil-water system was preequilibrated for one week. preequilibrated for one week.

This pilot study demonstrates the feasibility of utilizing instructional theories, specifically on learning motivation, to evaluate a computer-based tutorial for the purpose of proposing effective instructional interventions. Keller's ARCS model of motivational design provides the conceptual framework to address motivational issues while developing instruction. The ARCS model has four dimensions: attention, relevance, confidence, and satisfaction. Keller's instructional material motivation survey measures student motivation along the ARCS dimensions and was modified for this study to evaluate students' motivation while using a computer-based tutorial. This study was conducted in an engineering problem-solving and computer tools course for first-year students. The studied computer-based instructional tutorial, M-Tutor/spl trade/, is designed for learning MATLAB/sup /spl reg// syntactical structures. A pre-post evaluation research design was employed. A coding system was developed to categorize qualitative responses into corresponding instructional components. Qualitative and quantitative data were triangulated for instructional intervention development.