bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and Mechanical Properties of TiN/NbN Multilayered Coating
Authors: Liu Chien Cheng , Liu Kuang I , Yan Huai Wei , Ma Chia Li , Huang Jow Lay
Published: March 2010

In this study, multilayers of TiN/NbN were deposited by d.c. magnetron sputtering on die steel substrates. The structure, morphology and nano-hardness were assessed using X-ray diffraction, atomic force microscopy (AFM), stylus profiler (XP-2 stylus profiler) and nanoindentation, respectively. Wear tests were performed on pin-on-disk configuration and dry sliding conditions, at 5N load by using hardened steel ball. The result shows TiN with highly (111) preferred orientation. On mechanical properties, Young’s modulus and hardness values increase for layers number increase. At 64 layers films had the highest nano-hardness, Young’s modulus values. The TiN/NbN multilayer films presented changes in its morphology becoming more granulated and density after heating up to 500°C. A significant decrease in friction coefficient has been achieved for TiN/NbN multilayers against steel ball.
Microstructures and Mechanical Properties of B4C-TiB2 Composite Prepared by Hot Pressure Sintering
Authors: Yue Xin Yan , Zhao Shu Mao , Yu Liang , Ru Hong Qiang
Published: March 2010

B4C-TiB2 composite was prepared using hot pressure sintering. The microstructures and mechanical properties of the B4C-TiB2 composite were investigated. The B4C-TiB2 composite with 43 mass % TiB2 showed the optimized properties. The relative density, hardness, flexural strength and fracture toughness of that were 98.2 %, 25.9 GPa, 458 MPa and 8.7 MPa•m1/2, respectively. A number of toughening mechanisms, including fine grain, crack deflection and grain pull-out, were observed during microstructural analysis of the composite. The fracture mode of the B4C-TiB2 composite was greatly affected by the existence of the second phase of TiB2.
Preparation of Hydroxyapatite/Chitosan Biological Coatings on Carbon/Carbon Composites
Authors: Li Ying Hua , Cao Li Yun , Huang Jian Feng , Zeng Xie Rong
Published: March 2010

Hydroxyapatite/Chitosan (HAp/CS) bio-coatings were prepared on the surface of carbon/ carbon (C/C) composites by hydrothermal electrophoretic deposition, using sonochemical process resulted HAp nanoparticles, isopropyl alcohol and chitosan as raw materials. The influences of hydro- thermal conditions and deposition voltage on the microstructures and morphologies of the as-prepared coatings were investigated. It was shown that homogenous and dense HAp/CS coatings on C/C composites are obtained by hydrothermal electrophoretic deposition. With the increase of deposition voltage, density and homogeneity of the as-prepared HAp/CS composite coatings are well improved. Due to the growth of HAp nanoparticles in the hydrothermal condition, the subsequent heat treatment of the HAp/CS coatings is not needed.
A Study of Different Sintering Routes on Properties of Ni-Al2O3 Hydrogen Separation Membrane
Authors: Vichaphund Supawan , Atong Duangduen
Published: March 2010

This work aimed to investigate the effect of different sintering routes on properties of Ni-Al2O3 membrane. Alumina powder was mixed with 10 wt% nickel powder by dried ball-milling. Then, the mixture powder was uniaxially pressed to a bar shape and sintered via different sintering conditions. First route, the Ni-Al2O3 specimen was sintered at 1300°C for 2 h under air and then reduced at 900°C for 2 h under H2 atmosphere. Second route, the specimen was sintered at 1300°C for 2 h under argon. After sintering process, the physical and mechanical properties of membrane obtained from two routes were compared and discussed.
Preparation and Characterization of Different Composition Mg-Cu Tapes
Authors: Li Jun , Luo Guo Qiang , Shen Qiang , Zhang Lian Meng
Published: March 2010

Tape casting was used for the preparation of Mg-Cu systems density graded materials. A series of tapes with uniform compositions ranging from 100wt% Cu to 100wt% Mg were fabricated with sufficient strength to be handled during the post-processing stage. The effect of the tape casting process parameters on the properties of the tape were studied, such as the composition of the Mg-Cu and the solid loading. The rheology of the slurry of different Mg-Cu composition for tape casting was characterized by viscosity. The tapes characterized by microstructure, thickness and bulk density were outlined. The results demonstrated that the different Mg-Cu composition slurry with well-dispersed, high stability, certain solid loading from 45 ~70 wt% were obtained. The viscosity of the slurry and the density of the green tapes were increased with the increasing of the content of Mg. The thickness of tapes of compositions ranging from 100wt% Cu to 100wt% Mg with certain strength could be achieved 68-110μm and the density of the tapes was 0.74-2.42g/cm3. For 100wt% Cu tapes, when the solid loading was 68wt%, the high density tape was produced. The tapes with different thickness, density and different Mg-Cu compositions were obtained.
The Study of Nanostructured Interfacial Coatings on SiC Fibers by Atomic Force Microscopy
Authors: Baklanova Natalia I. , Zaitsev B.N.
Published: March 2010

Adhesion force measurements by atomic force microscopy (AFM) have been carried out to investigate the adhesion between the Si3N4 cantilever tip and the surface of the initial SiC-based Hi-Nicalon, Hi-Nicalon S, and Tyranno-SA fibers, as well as the ZrO2-coated and oxidized coated fibers. It was shown that the application of coating resulted in a change of the roughness parameters and a decrease of the adhesive forces between the Si3N4 cantilever tip and the fiber surface. Surface heterogeneity at the nanoscale could be responsible for the dispersion of adhesive forces. The results open the possibility of transferring nano mechanical information to meso or macro mechanical properties of ceramic matrix composites.
Damage Detection in Fibre Reinforced Ceramic and Metal Matrix Composites by Acoustic Emission
Authors: Kaya Figen
Published: March 2010

In this work damage micro-mechanisms of two different types of fibre reinforced composites are investigated by acoustic emission, AE. Ceramic based oxide fibre reinforced mullite matrix composite and metallic based SiC fibre reinforced titanium matrix composites exhibit different fracture mechanisms during loading and AE technique could pinpoint these damage mechanisms based on the AE responses detected simultaneously. The results show that in a ceramic matrix composite, the identification of fibre fracture and matrix cracking requires careful analysis of the AE data as both fibres and matrix break in brittle manner. Whereas the separation of fibre fracture from the ductile tearing of matrix ligaments could be easier in metallic based composites, such as titanium matrix composites.
Phase Evolution and Microstructure Characteristics of Calcium Phosphate Based Glass Ceramics Prepared by Sol-Gel Technique
Authors: Li Xu Dong , Cai Shu , Zhang Wen Juan , Zhang Zhe
Published: March 2010

Calcium phosphate based glasses and glass-ceramics in the system of 54CaO-36P2O5- (10-x)Na2O-xSrO were fabricated by sol-gel method. The structures of the glasses were investigated by Fourier transform infrared spectroscopy and X-ray diffraction has been used to determine the crystallize phase from glass matrix. The synthesized glass matrix shows a metaphosphate-like structure which consists of a chain and /or ring structure. After sintered at 1150 °C, the crystalline phase -Ca2P2O7 and a small quantity of amorphous glass were observed clearly. With 1.0 mol% addition of SrO, the average grain size of -Ca2P2O7 was obviously decreased and some of them were covered with amorphous glass. When the content of strontium reached to 5.0 mol%, only a little crystalline phase -Ca2P2O7 can be found in the glass matrix, while the grain size has no significant change, compared with that of the sample containing 1.0 mol% SrO. The results showed that SrO addition to 54CaO-36P2O5-10Na2O system can inhibit the crystallization of -Ca2P2O7 and decrease the grain size, and then adjust the degradation rate in body fluid by controlling the ratio of -Ca2P2O7 to amorphous glass.
Controlled Growth and Self-Assembly of CaCO3 Superstructures between the Organic-Water Interfaces
Authors: Liang Xiao Hong , Xiang Jun Hui , Zhang Fu Shi , Xing Li , Song Bo , Chen Shi Wei
Published: March 2010

In this paper, the crystallization behavior of calcium carbonate between the organic-water interfaces using a slow gas-diffusion procedure is studied. The organic-water interfaces can control the crystallization of calcium carbonate to form a flower-shaped superstructure. The precipitates of calcium carbonate were identified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A possible mechanism about the self-assembly process of CaCO3 crystals has been analyzed. It is found that the morphology of CaCO3 superstructure depends on the properties of organic solvent. This paper also presents the influence of surfactant monolayer, between the biphase interfaces, on the CaCO3 superstructure. This study suggests that it is possible to control morphogenesis of calcium carbonate by a combination of a surfactant monolayer with the organic-water interfaces.
Preparation of Porous HAW/ß-TCP Ceramics with In Situ Synthesis of HA Whiskers
Authors: Zan Qing Feng , Han Yao Cong , Dong Li Min , Wang Chen , Tian Jie Mo
Published: March 2010

Adding whiskers to ceramic was a way that has been used to strengthen the ceramics matrix. For porous materials, strength of pore walls was an important factor for strength of the whole materials. Porous calcium phosphate ceramics were always used as scaffolds of bone tissue engineering because of their biocompatible and osteoconductibility. In this work, HA whiskers were born in the porous -TCP ceramic during in situ procedure. The HA whiskers with about 2m for length and 100nm for diameter were observed from SEM photographs of as-fabricated porous HA ceramics, and the phase content was determined by XRD.
Porous β-Tricalcium Phosphate Composite Scaffold Reinforced by K2HPO4 and Gelatin
Authors: Ji Jin Gou , Yuan Xiao Yu , Xia Zhi Ning , Liu Peng Peng , Chen Ji Da
Published: March 2010

To improve the mechanical strength of porous β-tricalcium phosphate (β-TCP) scaffold, porous β-TCP composite scaffold was prepared by immersing as-sintered porous β-TCP scaffold mixed with K2HPO4 in gelatin solution, following vacuum drying and glutaraldehyde cross-linking. The pattern of samples was characterized by X-ray diffraction (XRD). The surfaces of samples were analyzed by scanning electron microscopy (SEM). The compressive strength of samples was measured by universal test machine. The porosity percentage of samples was investigated by Archimedes method. The effects of time of samples incubating in simulated body fluid (SBF) on compressive strength and weight loss of samples were also studied. The results show that the compressive strength and water-retention rate of samples can be improved by the K2HPO4 and gelatin. The decrease rate of compressive strength and weight loss of samples is greater initially, and then slower compared with that of β-TCP scaffolds. When the samples incubate in SBF about 45d, the compressive strength and weight become increase, and finally are greater than that of β-TCP scaffold.
Fabrication and Characterizations of YSZ Electrolyte Films for SOFC
Authors: Han Min Fang , Yang Zhi Bin , Liu Ze , Le Hui Rong
Published: March 2010

Yttria stabilized zirconia (YSZ) has been widely used as electrolyte in solid oxide fuel cell (SOFC). The effect of fabrication process on the properties of YSZ electrolyte thick film is discussed in the paper. With YSZ nano-powders of about 20-60nm as raw material, YSZ green adobe was fabricated by tape calendering process. Three-step sintering process was performed firstly holding at 1000°C for 2h, then raising to 1300~1400°C, then decreasing to 1200~1300°C within 30 minutes, and finally calcining at 1200~1300°C for 5~20 hrs. Dense YSZs with relative density of 96-99% are obtained; the grain size of YSZ was reduced to 0.5-3µm. During the process of grain growth, there are both grain boundary diffusion and grain boundary migration. The feasibility of densification without grain growth relies on the suppression of grain boundary migration while keeping grain boundary diffusion active at a temperature as low as 1200~1300°C. Whereas the electric conductivities of the YSZs are even higher than that obtained in conventional single step sintering process. The process is applied to the anode-supported SOFCs co-fired at 1250~1300°C, and the cathode-supported SOFCs co-fired at 1200~1250°C.
Mechanical Property and Ballistic Performance of Silicon Carbide
Authors: Ma Tian , Du Heng , Yan Zi Li , Li Zheng Cao , Zhang Jian Chun
Published: March 2010

Two groups of silicon carbide ceramics were prepared by pressureless sintering processing with a small amount of boron and carbon as sintering additives. The flexural strength, Vickers hardness, fracture toughness and compressive strength of the samples were measured and compared. Sample A achieved much higher flexural strength (389.4MPa) than that of sample B (250.3MPa) due to the difference of additive dosage. However, the two groups of samples attained comparable values for the other three mechanical properties. SEM observation revealed that the stoichiometric ratio of the Si/C atom in the sintered body is an important factor to affect the mechanical performance of the silicon carbide. The ballistic performance of the samples was also evaluated in this study. The results showed that sample B exhibited more excellent ballistic property, which is probably related to the high flexural strength. The detailed influencing factors need to be studied further.
Effect of Al2O3 Xerogel on the Microstructure and the Properties of Laser Cladding Coating of Fe-Based Alloy
Authors: Zhao Shi Hai , Jiang Xiu Ming , Huai Xu Guo , Fan Xiao Wei
Published: March 2010

Laser cladding Fe-based alloy coatings with 0, 3, 6, 9, 12 and 15% Al2O3 xerogel on 45 steel substrates were prepared by 5kWCO2 continuous wave laser. The effect of the content of Al2O3 xerogel on the microstructure, microhardness and wear resistance of the coatings was investigated by scan electron microscope, X-ray diffraction. The results show that the microstructure and properties were different when the content of Al2O3 xerogel changed. The addition of Al2O3 xerogel can enhance the fluidity of molten liquid and refine the microstructure. Adding adequate amount of Al2O3 xerogel to Fe-based alloy can improve the hardness and the wear resistance due to the nano-Al2O3 particles on surfaces and the dispersion strengthening and hardening of nano- Al2O3 particles.
Comparative Analysis of Adding Hydrogen Peroxide or Ethanol in Preparation of Zirconia Nano-Powder by Coprecipitation Methods
Authors: Wang Kai Jun , Hu Jin , Wang Hua , Liu Jian Liang , Cai Xiao Lan , Gao Wen Gui
Published: March 2010

Zirconia precursor was prepared by adding hydrogen peroxide or ethanol in co-precipitation process from raw materials of ZrOC12•8H2O and ammonia, the zirconia powders were subsequently obtained by calcination of the precursor at 600°C and ball milling. Through the analyzed by TG-DTA, XRD, SEM, the results show that by adding hydrogen peroxide or ethanol in co-precipitation process can reduce the produce of agglomerate. Ethanol and hydrogen peroxide addition on zirconia by co-precipitation for different reaction results were compared and analyzed.
Synthesis of Fe-Core/Au-Shell Nanoparticles under Ambient Pressure
Authors: Chao Shi Mian , Meen Teen Hang , Chen Wen Ray , Wu Kuen Hsien , Liu Yu Sung , Tzou Wen Cheng , Huang Chien Jung
Published: March 2010

Pure metal iron nanoparticles are unstable in the air. By a coating iron on nanoparticle surface with gold, these air-stable nanoparticles are protected from the oxidation and retain most of the favorable magnetic properties. However, it is difficult to prepare Fe-core/Au-shell (Fe@Au) nanoparticles under ambient pressure because iron nanoparticles are very easily to be oxidized in the air. In this study, we synthesized Fe@Au nanoparticles by modified reverse micelle method under ambient pressure and investigated them by X-ray diffraction, transmission electron microscopy (TEM), ultraviolet-visible absorption spectra, and magnetic susceptibility measurements. X-ray diffraction analysis shows that the pattern of iron is hidden under the pattern of gold. TEM image reveals that the core-shell structure is obviously observed and the average size of Fe@Au nanoparticles is about 12 nm, with about 8 nm diameter core and 2 nm shell. The absorption band of the Fe@Au nanoparticles shifts to a longer wavelength and broadens relative to that of the pure gold. The magnetic susceptibility of Fe@Au nanoparticles is measured with a SQUID magnetometer and found to be superparamagnetic with a blocking temperature Tb ~25 K.
A Novel Technique of Flyash Utilization: Preparation of Silica from Flyash by Alkali Leaching
Authors: Guo An Ran , Liu Jia Chen , Sun Yi Bing , Lian Wen Jun , Yang Lu
Published: March 2010

A new technique of flyash utilization was presented and high-purity silica was prepared by alkali leaching. The flyash was added into sodium hydroxide solution, and then the suspension was heated to 115 °C for 30 min. After filtrated, the filtrate was collected and carbon dioxide was imported into the solution. Finally, the silica would precipitate from the solution. The silica was characterized by scanning electron microscopy, X-ray diffraction and X-ray fluorescence spectrometer. The high-purity silica prepared from flyash was qualified for the rubber reinforcing agent used in shoemaking.
Environmental Pollution and Pollution Control in Chinese Ceramic Industry
Authors: Song Jing , Cheng Tao , Zhou Li Wei
Published: March 2010

This article describes various kinds of environmental pollution of ceramic industry in China, such as dust pollution, smoke pollution, water pollution and waste pollution of ceramics factories. In addition, some effective methods to control the pollution in ceramic factories are also discussed.
Properties of Silica Ceramic Made from Amorphous Silica
Authors: Wang Cai Fen , Liu Jia Chen , Guo Ji Ping , Song Di , Lian Wen Jun
Published: March 2010

The mixture of amorphous silica extracted from coal fly ash and fused silica was used to prepare density silica ceramic through slip-casting method. The XRD results showed that a large amount of cristobalite was formed at 1300°C which can weaken mechanical properties. The SEM results showed that glassy phase present from fused silica promoted ceramic densification. According to the experiment results, it was found that the bending strength was highest when mixing 65wt% fused silica and sintering at 1200°C for 4 hours.
Machining Behavior of Green RBSC Body Prepared by Gel-Casting
Authors: Liu Hai Lin , Huo Yan Li , Wang Chun Peng , Tang Jie , Wang Hua , Chen Yu Feng
Published: March 2010

In this paper, the green RBSC was prepared by gel casting process. The influences of the monomer content (MBAM and AM) and monomer ratio (MBAM to AM) on the flexural strength were investigated. The results indicated the flexural strength of green body was up to 8MPa and the micro- structures were homogeneous. The green RBSC bodies were machined by CNC grinding machine with diamond-coated grinding tools. Machining tests showed the green component could be machined without appended defects. It was found that green machining as a ‘top-down’ approach was a potential alternative for the rapid fabrication of complex-shaped ceramics, especially for some one-of-a-kind products.
Large Bulk Al2O3/ZrO2 (Y2O3) Nanocrystalline Composites Prepared by Combustion Synthesis under High Gravity
Authors: Zhao Zhong Min , Zhang Long , Pan Chuan Zeng , Yang Quan , Qu Zhen Sheng , Su Guan Ling , Huang Xue Gang , Wang Min Quan
Published: March 2010

The large bulk Al2O3/ZrO2 (Y2O3) eutectics were achieved by combustion synthesis in high-gravity field. With increasing high-gravity level, the matrix of eutectics transformed the rod-shaped colonies from the cellular ones, and the nanocrystalline microstructures came into existence as the high-gravity level was larger than 200g. The relative density, hardness, flexural strength and fracture toughness increased simultaneously with increasing high-gravity level, and reached the maximum values of 98.6%, 18.6GPa, 1248MPa and 15.6MPa•m1/2 respectively as the high-gravity level was 250g.
Influence of Calcination Time on Pozzolanic Activity of Metakaoline Base on a Novel Evaluation Method
Authors: Wang Mei Rong , Lin Tie Song , He Pei Gang , Jia De Chang
Published: March 2010

A novel evaluation method of pozzolanic activity of metakaoline is studied. The pozzolanic activity can be evaluated by the measurement of the content of AlO4 tetrahedra. Base on this method, the influence of calcination time on pozzolanic activity of metakaoline is studied. The results indicate that the pozzolanic activity increases with the calcination time when calcination time is below 4 hours, and it decreases with the calcinations time increasing when the calcination time is 4-8 hours.
"Why not? But I can't" – Influence of a 'culture of poverty' on learning - A case study
Authors: Perera Marie
Published: March 2010

Based on a sub set of data from a study which investigated the role of motivation as a contributing factor in second language learning in a disadvantaged school setting in Sri Lanka, this paper attempts to show the relationship between a ‘culture of poverty' and learning. Lewis, (1970 : p.85) states that ‘in addition to being a condition of chronic economic poverty, the culture of poverty is characterized by the cognitive poverty of its ‘members', instilling a fatalism with reference to any possibility of ever achieving a different way of life'.  Although education is one way in which such people could be empowered to develop a sense of self confidence and self worth, children acquire the adult fatalism early and become learned helpless. The findings of the study indicate that there is a correlation between motivation and a 'culture of poverty'. Further, in spite of the adverse socio-economic backgrounds from which the students come, their motivation to learn the second language can be enhanced. However, it is not the 'culture of poverty' per se that affects motivation but the type of attributions that the students make regarding their prior learning experiences. Thus a relationship between attributions and 'cognitive poverty' was visible. DOI: 10.4038/suslj.v6i1.1687 Sabaragamuwa University Journal, vol 6, no. 1, pp 23-34
The Effect of Macroeconomic Variables on Stock Prices in Emerging Sri Lankan Stock Market
Authors: Menike LMCS
Published: March 2010

This study investigates the effects of macroeconomic variables on stock prices in emerging Sri Lankan stock market using monthly data for the period from September 1991 to December 2002. The multivariate regression was run using eight macroeconomic variables for each individual stock.  The null hypothesis which states that money supply, exchange rate, inflation rate and interest rate variables collectively do not accord any impact on equity prices is rejected at 0.05 level of significance in all stocks. The results indicate that most of the companies report a higher R2  which justifies  higher explanatory power of macroeconomic variables in explaining stock prices.  Consistent with similar results of the developed as well as emerging market studies, inflation rate and exchange rate react mainly negatively to stock prices in the Colombo Stock Exchange (CSE). The negative effect of Treasury bill rate implies that whenever the interest rate on Treasury securities rise, investors tend to switch out of stocks causing stock prices to fall. However, lagged money supply variables do not appear to have a strong prediction of movements of stock prices while stocks do not provide effective hedge against inflation specially in Manufacturing, Trading and Diversified sectors in the CSE.  These findings hold practical implications for policy makers, stock market regulators, investors and stock market analysts. DOI: 10.4038/suslj.v6i1.1689 Sabaragamuwa University Journal, vol 6, no. 1, pp 50-67
An Empirical investigation of the Impact of Organizational factors on the Perceived Job Performance of Shop Floor Employees of Large scale Garment Industries in Sri Lanka
Authors: Kalyani LD
Published: March 2010

Existing literature reveals a gap in the empirical knowledge in respect of organizational factors that impact perceived job performance (PJP) at the large scale garment industries. The present study empirically evaluated four organizational factors that could have impact on the perceived job performance namely Leadership Style, Organization Structure, Organization Culture and Performance Evaluation. The study involved 236 shop floor employees who were selected randomly from 12 large scale garment factories in each province except North and North East provinces in Sri Lanka. Methods such as univariate, bivariate, regression and hypothesis testing were used for data analysis. The results indicated that all the independent variables were positively and significantly correlated to the perceived job performance. However, results regressing the independent variables on the perceived job performance showed that Leadership style, Organization Structure and Performance Evaluation are strong predictors of perceived job performance while organization culture variable is excluded from the model. On the whole, the independent variables accounted for almost 36% of the variance in the perceived job performance. DOI: 10.4038/suslj.v6i1.1691 Sabaragamuwa University Journal, vol 6, no. 1, pp 82-92
A floristic analysis of the vegetation of Platberg, eastern Free State, South Africa
Authors: Brand Robert F. , Brown Leslie R. , Du Preez Pieter J.
Published: March 2010

A checklist of vascular plants of Platberg was compiled to determine species richness, rarity and endemism. The floristic analysis is part of the Department of Economic, Tourism and Environmental Affairs Free State biodiversity assessment programme and conservation management plan for Platberg. The analysis identified a total of 669 species belonging to 304 genera and 95 families, with 214 species belonging to the Monocotyledoneae and 438 species to the Dicotyledoneae. The largest family is Asteraceae with 126 species, followed by Poaceae with 73 species, Cyperaceae with 39 species, Fabaceae with 33 species, and Scrophulariaceae with 27 species. Various fynbos species were found, as well as 26 endemic/near-endemic species belonging to the Drakensberg Alpine Centre or Eastern Mountain Region. The results of this study revealed that Platberg shares inselberg floral richness and endemism that can be tracked via the Afromontane archipelago-like string of inselbergs and mountains, which stretch north through the Chimanimani Mountains, into Malawi, the Eastern Arc Mountains via Tanzania and north through Ethiopia, into Eurasia.Conservation implications: Platberg, as an inselberg, is a site of significant biological diversity, with high species richness, vegetation selection and ecosystem complexity. It shares floral richness and endemism via inselbergs and mountains throughout Africa. The high species richness, Red Data species and ecosystems make this area an important conservation site that should be legislated and protected.
Myoelectrical activity of gastric antrum in conscious piglets around weaning
Authors: Lesniewska Violetta , Lærke Helle N. , Hedemann Mette S. , Jensen Bent B. , Højsgaard Søren , Pierzynowski Stefan G.
Published: March 2010

We investigated gastric myoelectrical activity in piglets around weaning. The study was carried out on the same piglets before and after weaning. Before weaning, the piglets were kept with their littermates and nursed by the sow, then they were weaned on solid dry food (standard concentrate for weaning pigs) and fed three times a day. Gastric myoelectrical activity was recorded in conscious animals using bipolar electrodes implanted on the wall of the terminal antrum. A cyclic activity pattern of the antral region in the stomach was present in both suckling and weaned piglets and consisted of quiescence and an activity phase. Sow's milk under nursing conditions significantly decreased the frequency of response potentials in ERA (electrical response activity). However, milk did not influence the basic electrical rhythm (BER) i.e., frequency of ECA (electrical control activity) and did not affect the periodicity of the cyclical activity. After weaning, ingestion of solid feed increased the BER, the frequency of ERA and the frequency of response potentials of ERA and slightly affected the periodicity of the cyclical activity. Key words: Gastric terminal antrum, piglet, weaning, electromyography
Effect of stage of growth of alfalfa on the incidence of bloat in cattle
Authors: Thompson D. J. , Brooke B. M. , Garland G. J. , Hall J. W. , Majak W.
Published: March 2010

Alfalfa of different maturities was produced simultaneously by varying the timing of the first cut. Groups of fistulated steers were confined and simultaneously fed alfalfa herbage at three stages of growth once a day. More bloat occurred during the vegetative stage of growth, it declined during bud development, and it was absent during bloom. This pattern occurred with both the number of cases of bloat and with the severity of bloat, which was much greater during the vegetative stage. Feed quality components also varied significantly between stages as did the leaf:stem ratio. Key words: Cattle, bloat, legumes, Medicago sativa L
Metabolic responses of the whole body, portal-drained viscera and hind quarter to acute cold exposure and feeding in sheep: Effects of nonselective and selective β-adrenoceptor blockade
Authors: Miaron J. O. O. , Christopherson R. J.
Published: March 2010

Two experiments were conducted to study the adrenergic regulation of thermogenesis in sheep during acute cold exposure and feeding. Propranolol, a nonselective β-blocker, metoprolol, a β1-blocker and ICI 118551, a β2-blocker, were used to investigate the β-adrenoceptor mediated whole-body and organ oxygen consumption (VO2). Whole-body oxygen consumption was measured by open circuit calorimetry. Portal-drained viscera and hindquarter oxygen consumption was the product of arterio-venous oxygen concentration difference and blood flow across the respective organs. Acute cold exposure increased (P < 0.05) whole body and hindquarters VO2 by about 60% but, not that of the portal drained viscera. Feeding induced a 41% elevation (P < 0.05) in whole body and a nonsignificant increase in the portal drained viscera VO2. The β-adrenoceptor blockers suppressed the increase in whole body VO2 associated with acute cold exposure but, only the reduction induced by the β2-adrenoceptor antagonist (ICI 118551) was significant (P = 0.02). The response to feeding was not altered by the β-blockers. This study suggests that the β-adrenoceptor system plays a role in modulating whole body but not the portal-drained viscera acute cold-induced thermogenesis, and this modulation of energy expenditure may involve a β2 receptor subtype. Key words: Calorimetry, thermogenesis, cold, feed and sheep
The effects of grade, gender, and postmortem treatment on beef. II. Cooking properties and palatability attributes
Authors: Jeremiah L. E. , Aalhus J. L. , Robertson W. M. , Gibson L. L.
Published: March 2010

A total of 196 beef carcasses of two genders (steers and heifers) and four carcass grades were evaluated for the effects of grade (carcass fatness (B1 = 2 to 4 mm subcutaneous fat; A1 = 4 to 10 mm subcutaneous fat; and A2 = 10 to 15 mm subcutaneous fat)) and meat quality (B2 = dark cutters) and gender. These carcasses also received two postmortem treatments (conventional or high voltage electrical stimulation and 3 or 6 d of postmortem aging) to evaluate the interactive effects of postmortem treatments with grade and gender. Cooking properties, palatability attributes, and consumer acceptance ratings were assessed on the longissimus muscle and flavor and texture profiles were obtained from the semitendinosus muscle. Differences attributable to carcass grade in palatability attributes were in agreement with expected differences, based upon differences in carcass fatness. Gender exerted little influence on either cooking or palatability attributes. Carcass grade or fatness appeared to influence the responses in palatability elicited from high voltage electrical stimulation and postmortem aging. Although the minimum fatness required to assure palatable beef could not be determined from the present results, lean B1 carcasses exhibited greater responses to the postmortem electrical stimulation treatment than fatter A2 carcasses. Key words: Beef, palatability, consumer acceptance, cooking properties, grade, gender, stimulation, aging
Relevance of National Research Council feed composition tables in Alberta
Authors: Suleiman A. , Okine E. , Goonewardene L. A.
Published: March 2010

The nutrient concentrations of selected Alberta-grown whole barley grain (Hordeum vulgare L.), three pure hays of alfalfa (Medicago sativa L.), barley, oat (Avea sativa L.), and four pure crop silages of alfalfa, barley, corn (Zea mays L.), and oat were determined and compared with nutrient concentrations of similar forages and a cereal grain reported in the National Research Council (NRC 1984 and 1989) feed nutrient composition tables. In addition, the variations in nutrient concentrations within the selected Alberta feedstuffs were assessed as an indication of whether the feedstuffs should be analysed frequently for certain nutrients. The concentrations of zinc and copper in barley grain cultivated in Alberta were 248% and 60% of the NRC values, respectively. The phosphorus, manganese, sulphur, magnesium, CP, selenium and calcium concentrations in barley hay were 17, 18, 18, 22, 32, 50 and 100% higher than NRC values. However, the concentrations of Cu and Zn were only 18 and 40% of the NRC values. Data from the present study suggest that Alberta hays, silages and barley grain are different in nutrient concentrations from similar grain and forages reported by the NRC (1984, 1989). Due to a high percentage of Alberta feeds being below the suggested NRC requirement levels of the various trace minerals, use of NRC table values for Cu, Mn, Mg and Zn for barley hay, silage and grain, oat hay and silage, alfalfa hay and silage and corn silage could result in deficiencies of these trace minerals in beef and dairy cattle with possible adverse effects on productivity. Thus, there is a need to use Alberta-derived nutrient composition values for these elements in diet formulations for cattle in Alberta. The high CVs calculated for most of the nutrients in the selected Alberta feeds suggest that these feeds should be analysed more often in order to minimise costs of production due to nutrient shortfalls or excesses in diets formulated using nutrient values without the knowledge of variability in feed composition. Key words: Nutrient composition, variability, feedstuffs
Utilization of barley straw, chemically treated with ammonium sulfite, anhydrous ammonia or urea, by ruminants
Authors: Rode L. M. , Jakober K. D. , Kudo H. , Cheng K.-J.
Published: March 2010

Straw treated with anhydrous ammonia, ammonium sulfite, urea or left untreated was examined in a series of feeding experiments to determine the relative efficacy of the treatments to improve the nutritive value of barley straw. In exp. 1, diets containing ammonia- and ammonium sulfite-treated barley straw were more digestible (P < 0.05) than diets with untreated straw. In exp. 2, average daily gain (ADG) and voluntary feed intake (VFI) were greatest for heifers fed ammonia-treated straw, followed by heifers fed urea-treated straw, and then by heifers fed ammonium sulfite-treated straw. Heifers fed untreated straw had the lowest ADG and VFI (P < 0.05). Although ammonium sulfite treatment improved straw digestibility, the relatively low VFI resulted in ADG lower than for animals fed other treated straw. The low VFI was attributed to the high level of sulfur in the diet. Anhydrous ammonia and urea were found to be the most effective chemicals for improving the nutritive value of barley straw. Although ammonium sulfite was as effective an anhydrous ammonia in improving digestibility of straw, it cannot be recommended because the application rates, necessary for effective treatment, resulted in depressed feed intake. Key words: Urea, anhydrous ammonia, ammonium sulfite, straw, digestibility, cattle
Effect of fish oil and monensin on milk composition in dairy cows
Authors: Cant J. P. , Fredeen A. H. , MacIntyre T. , Gunn J. , Crowe N.
Published: March 2010

Four primparous Holstein cows were used in a 4 × 4 Latin square with 21-d periods to determine the effect of redfish oil and monensin sodium on milk composition. The four dietary treatments were a basal diet (control), the basal diet plus 14.5 mg monensin kg−1 dietary dry matter (M), 2% fish oil (FO), and a combination of fish oil and monensin (FO + M). Total DM intake, measured during the last week of each period was reduced on the two fish oil treatments but an interaction with monensin depressed intakes further. An additive inhibition of rumen fibre degradation is discussed. Differences in yields of milk and lactose were not shown to be significant among treatments. Milk fat content was reduced 29.8% by fish oil supplementation and protein content dropped 5.3%. Protein:fat ratios increased from 0.78 on the control ration to 1.08 on the fish oil treatments. Monensin, on the other hand, only caused a change in milk fat percentage, and that by a 7.5% decline. Fish oil increased the concentrations of 20- and 22-carbon fatty acids in milk, including the n-3 eicosapentaenoic and docosahexaenoic acids which were transferred at 9.3 and 16.2% efficiency from the diet, respectively. Monensin had no effect on milk fatty acid profile. The fish-oil-by-monensin interaction produced the poorest energy intakes and rates of energy deposition into milk. Key words: Milk composition, fish oil, monensin, omega-3 fatty acids
Occurrence of fungal species in stored alfalfa forage as influenced by moisture content at baling and temperature during storage
Authors: Undi M. , Wittenberg K. M. , Holliday N. J.
Published: March 2010

A study was conducted to evaluate the effect of moisture content at baling on fungal growth during storage of alfalfa forage. Alfalfa forage was baled at DM contents of 64.1–66.2% (Low), 71.9–73.2% (Medium) and 75.4–77.4% (High) and was sampled 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 21, 35 and 60 d after storage. For each sample, abundance of fungal and yeast species was assessed by plating on media. Total fungal counts, number of species, species diversity, and species dominance were subjected to analysis of variance, and variation in the fungal assemblages was characterized by ordination. Total fungal counts, number of species, species diversity, and species dominance were not influenced (P > 0.05) by moisture content in the early (days 1 to 8) storage phase. Moisture content at baling did influence (P < 0.05) total counts, number of species, and species dominance in the latter phase (days 9 to 60) of storage. Total fungal counts were highest in Low DM forage, and number of species highest in Medium DM forage. Species dominance was highest in High DM forage. Low DM forage was associated with Aspergillus fumigatus, Mucor spp., Absidia spp., Emericella nidulans, and thermotolerant hyphomycetes. Aspergillus repens, Absidia spp. and some yeasts were more predominant in Medium and High DM forages. Moisture content and temperature were related to species assemblages during storage but water-soluble carbohydrate concentration, crude protein concentration and total bacteria counts were not. "Field" fungi, Phoma, Alternaria, Cladosporium spp. and most yeasts were eliminated within 8 d of storage. Physical conditions created in the early stages of storage likely affected fungal growth in the later storage phase. Key words: Moisture content, temperature, storage, alfalfa hay, fungal species, diversity
Serum mineral concentrations in relation to parturition in beef heifers and cows fed conserved forage
Authors: Small Julie A.
Published: March 2010

A study was undertaken to examine the relationship between serum mineral concentrations and calving ease in beef cattle fed conserved forage. Jugular blood samples were taken from multiparous cows (n = 6) and 2-yr-old primparous heifers (n = 9) that calved without assistance and 2-yr-old primparous heifers that required assistance with calving (n = 6) on days −7, 0 and +7 after parturition. Sera were analyzed for Ca, P, Mg, K, S, Na, Cu, Zn and B by ICAP and for progesterone by RIA. From 2 mo before and throughout the calving season cattle were given ad libitum round bale grass-legume silage (2.89% K; 3.4% P; 13% CP, 40% ADF; 38% DM). Heifers were also given 0.5 kg hd−1 d−1 of a grain supplement beginning 3 wk before calving. At calving, cows and heifers were in moderate body condition (5.26 ± 0.14 BCS) and heifers had reached 85% of mature body weight (475 ± 26 kg). Serum progesterone concentrations were highest (P < 0.05) at −7 d and dropped below 1 ng mL−1 at parturition and +7 d. Concentrations of serum Mg, S and K were highest (P < 0.05) whilst concentrations of P, B and Cu were lowest (P < 0.05) at parturition. However, serum Mg and S also differed (P < 0.05) among calving groups because concentrations were lowest for heifers with assisted calvings and, serum K concentrations were influenced (P < 0.05) by interaction between calving group and time because K concentrations increased at parturition only in cows and heifers with unassisted calvings. Serum Zn, Ca, and Na were not (P < 0.05) influenced by calving group or time. It is concluded that Mg, S, K, P, B and Cu metabolism are involved in the physiology of parturition and Mg, S and K metabolism may be particularly important for calving ease in primparous beef heifers fed conserved forage. Key words: Parturition, minerals, beef cattle, potassium, boron, magnesium
Weight gain and feed utilization of Hereford steers exposed to diazinon
Authors: Danielson T. J. , Golsteyn L. R.
Published: March 2010

Body weights and feed consumption were monitored in 48 Hereford steers, under feedlot conditions, for 10 wk after exposure to diazinon, an organophosphate insecticide. Experimental design consisted of four complete blocks, each of four treatment groups (positive and negative controls, two insecticidal ear tags and four insecticidal ear tags). Plasma cholinesterase activity was reduced by 50%, 24 h after topical application of diazinon directly to the skin (positive control) but was not reduced after attachment of either two or four insecticidal ear tags per animal. Daily weight gain and feed utilization in control animals, during the 70-d study, were 1.21 ± 0.22 kg d−1 and 0.144 ± 0.007 kg kg−1 (dry matter basis) and were not altered in steers exposed to diazinon. Key words: Cattle, diazinon, weight gain, cholinesterase
Effect of dietary flaxseed on broiler growth, erythrocyte deformability, and fatty acid composition of erythrocyte membranes
Authors: Bond J. M. , Julian R. J. , Squires E. J.
Published: March 2010

The effectiveness of flaxseed as a source of flax oil in broiler diets was determined in two separate experiments. Broiler growth, fatty acid composition of erythrocyte membranes and hematological variables were measured. We first examined the effect of 10, 20 or 30% flaxseed on growth in broilers and fatty acid composition of erythrocytes. The second experiment utilized hypobaric chambers to study the effect of a diet containing 20% flaxseed on growth, fatty acid composition of erythrocyte membranes, and hematological variables. In exp. 1, growth of the birds was reduced with increased inclusion of flaxseed. There was a reduction in the percentage of total saturated fatty acids in the erythrocyte membranes which was maximized with 20% flaxseed in the diet. In exp. 2, the growth of the birds was reduced with the inclusion of flaxseed in the diet. The deformability of the erythrocytes was not altered with the inclusion of flaxseed in the diet. There was a significant increase in the percentage of total saturated fatty acids in the erythrocyte membranes at ambient atmospheric pressure but not under hypobaric conditions with the inclusion of flaxseed in the diet. We conclude that the incorporation of flaxseed into broiler diets is not a practical source of flax oil for poultry due to decreased growth, possibly due to the presence of antinutritional factors. The effect of flaxseed on the fatty acid composition of the erythrocyte membranes may be dependent on the fat content of the diet. Key Words: Broiler, growth, flaxseed, erythrocyte deformability
Behaviour and productivity of pigs in groups composed of disproportionate numbers of littermates
Authors: Gonyou H. W.
Published: March 2010

Forty litters of eight pigs each were paired by age and weight and re-grouped at the beginning of a 12-wk grower/finisher period. Each pair of litters was assigned to two pens, with two pigs from one litter (Minority) and six pigs from the other (Majority) in each pen. Four pairs of litters were removed from the experiment due to loss of pigs from injury or poor health. Agonistic encounters following re-grouping were used to rank each Minority pig and to classify it as being within the Dominant or Subordinate half of the social hierarchy. Minority pigs within a pen tended to obtain similar social ranks (within two ranks in 20 of 30 pens; P < 0.05), but were as likely to be Dominant as Subordinate (11 vs. 9 pairs, respectively). The activity and position of all pigs were sampled once daily, 5 days a week. One Minority pig was designated as the focal pig for these observations. The second Minority pig was more likely to be engaged in the same activity as the focal pig than were Majority pigs (P < 0.01), and would lie closer to the focal pig than would the Majority pigs (P < 0.01). There were no differences in the proportion of Majority and Minority pigs which were removed from the experiment due to injuries, nor in the type of injuries requiring their removal. Examination of all pigs at the mid-point of the study revealed some evidence of injury on the head, ears, shoulders, back, flanks, ramp and tail of 76, 75, 87, 90, 91 and 95% of the pigs, respectively, but no differences between Majority and Minority pigs in location or severity of injuries. Average daily gain for the entire experiment was 775 g d−1, and did not differ between Majority and Minority pigs during any 2-wk period of the study. It is concluded that littermates continue to associate with each other after re-grouping and that they attain similar social status. However, the litter with the largest number of pigs present does not consistently achieve social dominance or a competitive advantage manifested in improved weight gain. Key words: Pigs, littermates, re-grouping, social status
Immunohistochemical localization of proteoglycans in bovine skeletal muscle and adipose connective tissues
Authors: Nakano T. , Li X. , Sunwoo H. H. , Sim J. S.
Published: March 2010

Monoclonal antibodies were used to immunolocate proteoglycans in bovine skeletal muscle and adipose connective tissues. Intense stainings with the anti-decorin antibody were observed in the epimysium, perimysium and adipose connective tissues. Weak but positive immunostainings for chondroitin sulphate were also observed in these tissues. Key words: Proteoglycan, glycosaminoglycan, muscle, adipose tissue, beef