WorldWideScience

Sample records for behavioral caste differentiation

  1. Newly developed vacuum differential pressure casting of thin-walled complicated Al-alloy castings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The newly designed vacuum differential pressure casting (VDPC) unit was introduced, by which the capability of the VDPC process to produce thin-walled complicated Al-alloy castings, that are free from oxides, gas pore and shrinkage cavity and thus enhance overall part quality, was studied. Experimental results were compared with those of traditional gravity pouring and vacuum suction casting. The first series of experiments were focused on investigating the castability of thin section Al-alloy casting. In the second series of experiments the metallographic evidence, casting strength and soundness were examined. Finally, case studies of very interesting thin walled complicated casting applications were described. The advantages of the described technique have made possible to produce thin walled complicated Al-alloy casting (up to a section thickness of 1 mm), which is not practical for gravity pouring and vacuum suction casting.

  2. Simulation research on control algorithm of differential pressure casting process

    Institute of Scientific and Technical Information of China (English)

    Chai Yan; Jie Wanqi; Yang Bo

    2009-01-01

    To improve the precision of the filling pressure curve of differential pressure casting controlled with PID controller,the model of differential pressure casting process is established and two pressure-difference control systems using PID algorithm and Dahlin algorithm are separately designed in MATLAB. The scheduled pressure curves controlled with PID algorithm and Dahlin algorithm,respectively,are comparatively simulated in MATLAB.The simulated pressure curves obtained show that the control precision with Dahlin algorithm is higher than that with PID algorithm in the differential pressure casting process,and it was further verified by production practice.

  3. Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

    OpenAIRE

    Olofsson, Jakob; Ingvar L. Svensson

    2012-01-01

    The industrial demand for increased component performance with concurrent reductions in component weight, development times and verifications using physical prototypes drives the need to use the full potential of casting and Finite Element Method (FEM) simulations to correctly predict the mechanical behavior of cast components in service. The mechanical behavior of the component is determined by the casting process, and factors as component geometry and casting process parameters are known to...

  4. Dynamic fracture behavior of nodular cast iron

    International Nuclear Information System (INIS)

    Ferritic nodular cast iron has been found to be a much tougher material than previously believed based on Charpy impact test results. As a result this material is being considered as a substitute for Stainless Steel in nuclear waste transport containers. We have determined Klc and Kld values for nodular cast iron with varying values of silicon and percentage of pearlite in the matrix. Regular V-notch charpy bars and fatigue precracked charpy bars have been tested to determine the initiation and propagation energy and the effect of notch acuity on transition temperature. (author)

  5. Queens become workers: pesticides alter caste differentiation in bees

    Science.gov (United States)

    dos Santos, Charles F.; Acosta, André L.; Dorneles, Andressa L.; dos Santos, Patrick D. S.; Blochtein, Betina

    2016-01-01

    Bees are important for the world biodiversity and economy because they provide key pollination services in forests and crops. However, pesticide use in crops has adversely affected (decreased) queen production because of increased mortality among larvae. Here, we demonstrated that in vitro-reared queens of a neotropical social bee species (Plebeia droryana) also showed high larval mortality after exposure to an organophosphate pesticide (chlorpyrifos) via larval food. Moreover, most of the surviving larvae that were destined to develop into queens became workers more likely because they ate less food than expected without pesticide skewing thus caste differentiation in this bee species. This adverse effect has not been previously reported for any other social insects, such as honeybees or bumblebees. Queens are essential for breeding and colony growth. Therefore, if our data are applicable to other pantropical social bee species across the globe, it is likely that these bees are at a serious risk of failure to form new colonies. PMID:27530246

  6. Queens become workers: pesticides alter caste differentiation in bees.

    Science.gov (United States)

    Dos Santos, Charles F; Acosta, André L; Dorneles, Andressa L; Dos Santos, Patrick D S; Blochtein, Betina

    2016-01-01

    Bees are important for the world biodiversity and economy because they provide key pollination services in forests and crops. However, pesticide use in crops has adversely affected (decreased) queen production because of increased mortality among larvae. Here, we demonstrated that in vitro-reared queens of a neotropical social bee species (Plebeia droryana) also showed high larval mortality after exposure to an organophosphate pesticide (chlorpyrifos) via larval food. Moreover, most of the surviving larvae that were destined to develop into queens became workers more likely because they ate less food than expected without pesticide skewing thus caste differentiation in this bee species. This adverse effect has not been previously reported for any other social insects, such as honeybees or bumblebees. Queens are essential for breeding and colony growth. Therefore, if our data are applicable to other pantropical social bee species across the globe, it is likely that these bees are at a serious risk of failure to form new colonies. PMID:27530246

  7. Volume Ray Casting with Peak Finding and Differential Sampling

    KAUST Repository

    Knoll, A.

    2009-11-01

    Direct volume rendering and isosurfacing are ubiquitous rendering techniques in scientific visualization, commonly employed in imaging 3D data from simulation and scan sources. Conventionally, these methods have been treated as separate modalities, necessitating different sampling strategies and rendering algorithms. In reality, an isosurface is a special case of a transfer function, namely a Dirac impulse at a given isovalue. However, artifact-free rendering of discrete isosurfaces in a volume rendering framework is an elusive goal, requiring either infinite sampling or smoothing of the transfer function. While preintegration approaches solve the most obvious deficiencies in handling sharp transfer functions, artifacts can still result, limiting classification. In this paper, we introduce a method for rendering such features by explicitly solving for isovalues within the volume rendering integral. In addition, we present a sampling strategy inspired by ray differentials that automatically matches the frequency of the image plane, resulting in fewer artifacts near the eye and better overall performance. These techniques exhibit clear advantages over standard uniform ray casting with and without preintegration, and allow for high-quality interactive volume rendering with sharp C0 transfer functions. © 2009 IEEE.

  8. Effect of Manganese on As-Cast Microstructure and Hardening Behavior of High Chromium White Cast Iron

    Institute of Scientific and Technical Information of China (English)

    SUN Zhi-ping; SHEN Bao-luo; WANG Jun; LIU Hao-huai; LUO Cheng

    2005-01-01

    The effect of manganese on the as-cast structure and hardening behavior of high chromium white cast iron subjected to sub-critical treatment was studied. The results indicate that the fraction of retained austenite and the manganese distribution in as-cast alloys are controlled by manganese content. The manganese distribution in as-cast alloys is not homogeneous. The manganese content in carbide is higher than that in matrix. Whether the secondary hardening occurs or not and the peak hardness of secondary hardening is controlled by manganese content in retained austenite in as-cast structure. Higher manganese content can cause more retained austenite. The secondary hardening occurs in sub-critical treating process if the fraction of retained austenite is high.

  9. Rheological behavior of continuous roll casting process of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    ZHAN Li-hua; ZHONG Jue; LI Xiao-qian; HUANG Ming-hui

    2005-01-01

    The rheological behavior of aluminum alloy and its influencing factors in physical simulation of continuous roll casting process were studied by using a Gleeble-1500 thermal-mechanical simulation tester with a set of special clamp system. The relationships between the flow stress and the strain rate in the deformation process of simulating roll casting experiment were obtained. The results show that four different characteristic stages exist in the temperature range of the whole rheological process. The first occurs when the temperature is higher than 600℃, which belongs to the creep deformation stage; the second occurs when the temperature lies in the range of 500-600℃, and it can be regarded as the high temperature and low stress level deformation stage; the third occurs when the temperature decreases to the range of 300-500℃, it is considered to be the middle stress level deformation stage; the last occurs when the temperature is less than 300℃ and the strain rate is less than 1.00 s -1, it belongs to middle stress level deformation stage. But when the strain rate is larger than 1.00 s -1, it belongs to the high stress level deformation stage. And the relative constitutive models suitable for the four different stages of continuous roll casting process were established through multivariate linear regression analysis of the experimental data.

  10. Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

    International Nuclear Information System (INIS)

    The industrial demand for increased component performance with concurrent reductions in component weight, development times and verifications using physical prototypes drives the need to use the full potential of casting and Finite Element Method (FEM) simulations to correctly predict the mechanical behavior of cast components in service. The mechanical behavior of the component is determined by the casting process, and factors as component geometry and casting process parameters are known to affect solidification and microstructure formation throughout the component and cause local variations in mechanical behavior as well as residual stresses. Though residual stresses are known to be an important factor in the mechanical behavior of the component, the importance of local mechanical behavior is not well established and the material is typically considered homogeneous throughout the component. This paper deals with the influence of solidification and solid state transformation on microstructure formation and the effect of local microstructure variations on the mechanical behavior of the cast component in service. The current work aims to investigate the coupling between simulation of solidification, microstructure and local variations in mechanical behavior and stress-strain simulation. This is done by performing several simulations of a ductile iron component using a recently developed simulation strategy, a closed chain of simulations for cast components, able to predict and describe the local variations in not only elastic but also plastic behavior throughout the component by using microstructural parameters determined by simulations of microstructural evolution in the component during the casting process. In addition the residual stresses are considered. The results show that the FEM simulation results are significantly affected by including microstructure based mechanical behavior. When the applied load is low and the component is subjected to stress levels

  11. Regulation of caste differentiation in the honey bee (Apis mellifera L.)

    NARCIS (Netherlands)

    Goewie, E.A.

    1978-01-01

    The nutritional environment of honey-bee larvae affects the juvenile hormone (JH) titre of larval haemolymph and tissues. In this investigation the mechanism for the regulation of caste differentiation has been studied.Chemo- and mechanoreceptors are found on larval mouthparts. Chemoreceptors on max

  12. Thermomechanical Behavior in Continuous Bloom Casting with Different Mold Tapers

    Institute of Scientific and Technical Information of China (English)

    LUO Xin; CHEN Yong; SHEN Houfa

    2008-01-01

    A two-dimensional finite element model was used to analyze the thermal and mechanical behavior dunng solidification of the strand in a continuous bloom casting mold.The coupled heat transfer and defermation were analyzed to simulate the formation of the air gap between the mold and the strand.The model was used to investigate the influence of mold taper on the temperature and stress distributions in the strand.The results show that the air gap mainly forms around the strand corner,causing a hoRer and thinner solidifying shell in this region.The mold taper partially compensates for the strand shell shnnkage and reduces the infiuence of the air gap on the heat transfer.The mold taper compresses the shell and changes the stress state around the stmnd comer region.As the strand moves down into the mold,the mold constraint causes compressive stress beneath the comer surface.which reduces the hot tear that forms on the strand.

  13. Methoprene and temperature effects on caste differentiation and protein composition in the Formosan subterranean termite, Coptotermes formosanus

    Science.gov (United States)

    The utilization of multiple caste is a shared feature of many social insects. In termites, multiple extrinsic factors have been shown to impact caste differentiation; for example, temperature has been shown to increase soldier production. The objective of this investigation was to examine and corr...

  14. Population differentiation of southern Indian male lineages correlates with agricultural expansions predating the caste system.

    Directory of Open Access Journals (Sweden)

    Ganeshprasad Arunkumar

    Full Text Available Previous studies that pooled Indian populations from a wide variety of geographical locations, have obtained contradictory conclusions about the processes of the establishment of the Varna caste system and its genetic impact on the origins and demographic histories of Indian populations. To further investigate these questions we took advantage that both Y chromosome and caste designation are paternally inherited, and genotyped 1,680 Y chromosomes representing 12 tribal and 19 non-tribal (caste endogamous populations from the predominantly Dravidian-speaking Tamil Nadu state in the southernmost part of India. Tribes and castes were both characterized by an overwhelming proportion of putatively Indian autochthonous Y-chromosomal haplogroups (H-M69, F-M89, R1a1-M17, L1-M27, R2-M124, and C5-M356; 81% combined with a shared genetic heritage dating back to the late Pleistocene (10-30 Kya, suggesting that more recent Holocene migrations from western Eurasia contributed <20% of the male lineages. We found strong evidence for genetic structure, associated primarily with the current mode of subsistence. Coalescence analysis suggested that the social stratification was established 4-6 Kya and there was little admixture during the last 3 Kya, implying a minimal genetic impact of the Varna (caste system from the historically-documented Brahmin migrations into the area. In contrast, the overall Y-chromosomal patterns, the time depth of population diversifications and the period of differentiation were best explained by the emergence of agricultural technology in South Asia. These results highlight the utility of detailed local genetic studies within India, without prior assumptions about the importance of Varna rank status for population grouping, to obtain new insights into the relative influences of past demographic events for the population structure of the whole of modern India.

  15. Nutritionally driven differential gene expression leads to heterochronic brain development in honeybee castes.

    Science.gov (United States)

    Moda, Lívia Maria; Vieira, Joseana; Guimarães Freire, Anna Cláudia; Bonatti, Vanessa; Bomtorin, Ana Durvalina; Barchuk, Angel Roberto; Simões, Zilá Luz Paulino

    2013-01-01

    The differential feeding regimes experienced by the queen and worker larvae of the honeybee Apis mellifera shape a complex endocrine response cascade that ultimately gives rise to differences in brain morphologies. Brain development analyzed at the morphological level from the third (L3) through fifth (L5) larval instars revealed an asynchrony between queens and workers. In the feeding phase of the last larval instar (L5F), two well-formed structures, pedunculi and calyces, are identifiable in the mushroom bodies of queens, both of which are not present in workers until a later phase (spinning phase, L5S). Genome-wide expression analyses and normalized transcript expression experiments monitoring specific genes revealed that this differential brain development starts earlier, during L3. Analyzing brains from L3 through L5S1 larvae, we identified 21 genes with caste-specific transcription patterns (e.g., APC-4, GlcAT-P, fax, kr-h1 and shot), which encode proteins that are potentially involved in the development of brain tissues through controlling the cell proliferation rate (APC4, kr-h1) and fasciculation (GlcAT-P, fax, and shot). Shot, whose expression is known to be required for axon extension and cell proliferation, was found to be transcribed at significantly higher levels in L4 queens compared with worker larvae. Moreover, the protein encoded by this gene was immunolocalized to the cytoplasm of cells near the antennal lobe neuropiles and proximal to the Kenyon cells in the brains of L4 queens. In conclusion, during the larval period, the brains of queens are larger and develop more rapidly than workers' brains, which represents a developmental heterochrony reflecting the effect of the differential feeding regime of the two castes on nervous system development. Furthermore, this differential development is characterized by caste-specific transcriptional profiles of a set of genes, thus pointing to a link between differential nutrition and differential

  16. Nutritionally driven differential gene expression leads to heterochronic brain development in honeybee castes.

    Science.gov (United States)

    Moda, Lívia Maria; Vieira, Joseana; Guimarães Freire, Anna Cláudia; Bonatti, Vanessa; Bomtorin, Ana Durvalina; Barchuk, Angel Roberto; Simões, Zilá Luz Paulino

    2013-01-01

    The differential feeding regimes experienced by the queen and worker larvae of the honeybee Apis mellifera shape a complex endocrine response cascade that ultimately gives rise to differences in brain morphologies. Brain development analyzed at the morphological level from the third (L3) through fifth (L5) larval instars revealed an asynchrony between queens and workers. In the feeding phase of the last larval instar (L5F), two well-formed structures, pedunculi and calyces, are identifiable in the mushroom bodies of queens, both of which are not present in workers until a later phase (spinning phase, L5S). Genome-wide expression analyses and normalized transcript expression experiments monitoring specific genes revealed that this differential brain development starts earlier, during L3. Analyzing brains from L3 through L5S1 larvae, we identified 21 genes with caste-specific transcription patterns (e.g., APC-4, GlcAT-P, fax, kr-h1 and shot), which encode proteins that are potentially involved in the development of brain tissues through controlling the cell proliferation rate (APC4, kr-h1) and fasciculation (GlcAT-P, fax, and shot). Shot, whose expression is known to be required for axon extension and cell proliferation, was found to be transcribed at significantly higher levels in L4 queens compared with worker larvae. Moreover, the protein encoded by this gene was immunolocalized to the cytoplasm of cells near the antennal lobe neuropiles and proximal to the Kenyon cells in the brains of L4 queens. In conclusion, during the larval period, the brains of queens are larger and develop more rapidly than workers' brains, which represents a developmental heterochrony reflecting the effect of the differential feeding regime of the two castes on nervous system development. Furthermore, this differential development is characterized by caste-specific transcriptional profiles of a set of genes, thus pointing to a link between differential nutrition and differential

  17. Hox gene expression leads to differential hind leg development between honeybee castes.

    Science.gov (United States)

    Bomtorin, Ana Durvalina; Barchuk, Angel Roberto; Moda, Livia Maria; Simoes, Zila Luz Paulino

    2012-01-01

    Beyond the physiological and behavioural, differences in appendage morphology between the workers and queens of Apis mellifera are pre-eminent. The hind legs of workers, which are highly specialized pollinators, deserve special attention. The hind tibia of worker has an expanded bristle-free region used for carrying pollen and propolis, the corbicula. In queens this structure is absent. Although the morphological differences are well characterized, the genetic inputs driving the development of this alternative morphology remain unknown. Leg phenotype determination takes place between the fourth and fifth larval instar and herein we show that the morphogenesis is completed at brown-eyed pupa. Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from hind leg imaginal discs of pre-pupal honeybees of both castes we present a list of 200 differentially expressed genes. Notably, there are castes preferentially expressed cuticular protein genes and members of the P450 family. We also provide results of qPCR analyses determining the developmental transcription profiles of eight selected genes, including abdominal-A, distal-less and ultrabithorax (Ubx), whose roles in leg development have been previously demonstrated in other insect models. Ubx expression in workers hind leg is approximately 25 times higher than in queens. Finally, immunohistochemistry assays show that Ubx localization during hind leg development resembles the bristles localization in the tibia/basitarsus of the adult legs in both castes. Our data strongly indicate that the development of the hind legs diphenism characteristic of this corbiculate species is driven by a set of caste-preferentially expressed genes, such as those encoding cuticular protein genes, P450 and Hox proteins, in response to the naturally different diets offered to honeybees during the larval period. PMID:22848371

  18. Hox gene expression leads to differential hind leg development between honeybee castes.

    Science.gov (United States)

    Bomtorin, Ana Durvalina; Barchuk, Angel Roberto; Moda, Livia Maria; Simoes, Zila Luz Paulino

    2012-01-01

    Beyond the physiological and behavioural, differences in appendage morphology between the workers and queens of Apis mellifera are pre-eminent. The hind legs of workers, which are highly specialized pollinators, deserve special attention. The hind tibia of worker has an expanded bristle-free region used for carrying pollen and propolis, the corbicula. In queens this structure is absent. Although the morphological differences are well characterized, the genetic inputs driving the development of this alternative morphology remain unknown. Leg phenotype determination takes place between the fourth and fifth larval instar and herein we show that the morphogenesis is completed at brown-eyed pupa. Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from hind leg imaginal discs of pre-pupal honeybees of both castes we present a list of 200 differentially expressed genes. Notably, there are castes preferentially expressed cuticular protein genes and members of the P450 family. We also provide results of qPCR analyses determining the developmental transcription profiles of eight selected genes, including abdominal-A, distal-less and ultrabithorax (Ubx), whose roles in leg development have been previously demonstrated in other insect models. Ubx expression in workers hind leg is approximately 25 times higher than in queens. Finally, immunohistochemistry assays show that Ubx localization during hind leg development resembles the bristles localization in the tibia/basitarsus of the adult legs in both castes. Our data strongly indicate that the development of the hind legs diphenism characteristic of this corbiculate species is driven by a set of caste-preferentially expressed genes, such as those encoding cuticular protein genes, P450 and Hox proteins, in response to the naturally different diets offered to honeybees during the larval period.

  19. Electrochemical behavior of Co-Cr and Ni-Cr dental cast alloys

    Institute of Scientific and Technical Information of China (English)

    Viswanathan S. SAJI; Han-Cheol CHOE

    2009-01-01

    The cast structures influencing the electrochemical corrosion behavior of Co-Cr and Ni-Cr dental alloys were studied using potentiodynamic polarization and AC impedance in 0.9% (mass fraction) NaCl solution at (37±1) ℃. The phase and microstructure of the alloys that were fabricated using two different casting methods viz. centrifugal casting and high frequency induction casting, were examined using X-ray diffraction analysis, scanning electron microscopy and energy dispersive spectroscopy. The roles of alloying elements and the passive film homogeneity on the corrosion resistance of Co-Cr-Mo and Ni-Cr-Mo dental cast alloys were reviewed. The results of electrochemical study show that the dependence of corrosion resistance on the microstructure associated with the casting methods is marginal. The Co-Cr alloy exhibits more desirable corrosion resistance properties than the Ni-Cr alloy. There is severe preferential dissolution of Ni-rich, Cr and Mo depleted zones in the Ni-Cr alloy.

  20. THE INVESTIGATION ON THE RHEOLOGICAL BEHAVIOR OF SEMI-SOLID ALUMINUM ALLOY DURING DIE CASTING

    Institute of Scientific and Technical Information of China (English)

    X.J. Yang; J. Lin

    2002-01-01

    Under the condition of die casting and reheating temperature of 570-580° C, the Rhe-ological behavior of semi-solid aluminum alloy (A356) is pseudoplasticity at the shearrate of 2×10s-1×104 s-1, and also shows dilatancy at the rate over 106s-1.

  1. Epigenetic (re)programming of caste-specific behavior in the ant Camponotus floridanus

    Science.gov (United States)

    Brady, Cristina M.; Enzmann, Brittany L.; Desplan, Claude; Ray, Anandasankar; Zwiebel, Laurence J.; Bonasio, Roberto; Reinberg, Danny; Liebig, Jürgen; Berger, Shelley L.

    2016-01-01

    Eusocial insects organize themselves into behavioral castes whose regulation has been proposed to involve epigenetic processes, including histone modification. In the carpenter ant Camponotus floridanus, morphologically distinct worker castes called minors and majors exhibit pronounced differences in foraging and scouting behaviors. We found that these behaviors are regulated by histone acetylation likely catalyzed by the conserved acetyltransferase CBP. Transcriptome and chromatin analysis in brains of scouting minors fed pharmacological inhibitors of CBP and histone deacetylases (HDACs) revealed hundreds of genes linked to hyperacetylated regions targeted by CBP. Majors rarely forage, but injection of a HDAC inhibitor or small interfering RNAs against the HDAC Rpd3 into young major brains induced and sustained foraging in a CBP-dependent manner. Our results suggest that behavioral plasticity in animals may be regulated in an epigenetic manner via histone modification. PMID:26722000

  2. Epigenetic (re)programming of caste-specific behavior in the ant Camponotus floridanus.

    Science.gov (United States)

    Simola, Daniel F; Graham, Riley J; Brady, Cristina M; Enzmann, Brittany L; Desplan, Claude; Ray, Anandasankar; Zwiebel, Laurence J; Bonasio, Roberto; Reinberg, Danny; Liebig, Jürgen; Berger, Shelley L

    2016-01-01

    Eusocial insects organize themselves into behavioral castes whose regulation has been proposed to involve epigenetic processes, including histone modification. In the carpenter ant Camponotus floridanus, morphologically distinct worker castes called minors and majors exhibit pronounced differences in foraging and scouting behaviors. We found that these behaviors are regulated by histone acetylation likely catalyzed by the conserved acetyltransferase CBP. Transcriptome and chromatin analysis in brains of scouting minors fed pharmacological inhibitors of CBP and histone deacetylases (HDACs) revealed hundreds of genes linked to hyperacetylated regions targeted by CBP. Majors rarely forage, but injection of a HDAC inhibitor or small interfering RNAs against the HDAC Rpd3 into young major brains induced and sustained foraging in a CBP-dependent manner. Our results suggest that behavioral plasticity in animals may be regulated in an epigenetic manner via histone modification. PMID:26722000

  3. Epigenetic (re)programming of caste-specific behavior in the ant Camponotus floridanus.

    Science.gov (United States)

    Simola, Daniel F; Graham, Riley J; Brady, Cristina M; Enzmann, Brittany L; Desplan, Claude; Ray, Anandasankar; Zwiebel, Laurence J; Bonasio, Roberto; Reinberg, Danny; Liebig, Jürgen; Berger, Shelley L

    2016-01-01

    Eusocial insects organize themselves into behavioral castes whose regulation has been proposed to involve epigenetic processes, including histone modification. In the carpenter ant Camponotus floridanus, morphologically distinct worker castes called minors and majors exhibit pronounced differences in foraging and scouting behaviors. We found that these behaviors are regulated by histone acetylation likely catalyzed by the conserved acetyltransferase CBP. Transcriptome and chromatin analysis in brains of scouting minors fed pharmacological inhibitors of CBP and histone deacetylases (HDACs) revealed hundreds of genes linked to hyperacetylated regions targeted by CBP. Majors rarely forage, but injection of a HDAC inhibitor or small interfering RNAs against the HDAC Rpd3 into young major brains induced and sustained foraging in a CBP-dependent manner. Our results suggest that behavioral plasticity in animals may be regulated in an epigenetic manner via histone modification.

  4. Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel-- A Comparison

    Institute of Scientific and Technical Information of China (English)

    Mehdi Mazar Atabaki; Sajjad Jafari; Hassan Abdollah-pour

    2012-01-01

    Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test.The wear test was carried out with different loads on a pin.Abrasive wear behavior of two alloys was evaluated by comparing mass loss,wear resistance,microhardness and friction coefficient.The microstructure of the specimens was detected using optical microscope.The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel.Due to the presence of M7C3 carbides on the high chromium cast iron matrix,impact crushers exhibited higher friction coefficient

  5. Comparison of corrosion behavior of ZL104 alloy at as-cast and heat treatment states

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The corrosion behavior of ZL 104 alloy at different states (as-cast and heat treatment) in salt spray corrosion (SSC) was studied. The results show that the sample treated after refinement and modification has the least corrosive resistance compared with the sample bearing as-cast structure at the beginning of the corrosion. As the corrosion process continued, however, the trend reversed itself. After 44 h continuous corrosion, the corrosive rates of all samples tend to be stable. After experiments, the sample bearing as-cast structure had the most corrosive products on the surface whereas the sample being refined and modified had the least products. The Fourier transformation infrared spectroscopy (FTIR)analyses of the corrosion products show that these products are composed of hydroxyl-containing substances.

  6. Non-dendritic structural 7075 aluminum alloy byliquidus cast and its semi-solid compression behavior

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Fine, equiaxed, non-dendritic structure needed by semi-solid processing was obtained by liquidus cast, i.e.7075 wrought aluminum alloy cast from liquidus temperature. The microstructures after heat treatment at different tem-peratures and time in the semi-solid range were observed, and the compression deformation behavior at different tempera-tures (490 ~ 600 C) and strain rates (5 × 10-3 ~ 5s-1) was investigated by means of Gleeble-1500 thermal-mechenicalsimulator. Thc results show that the deformation resistance of the non-dendritic structure attained by liquidus cast in semi-solid is remarkably lower than that of conventional dendritic structure. The formability of non-dendritic structure is betterthan that of dendritic structure

  7. Effect of Sn on as-cast ageing behavior of Al-Si-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    王桂青; 边秀房; 段佑峰; 张均艳

    2003-01-01

    The effect of minor additions of Sn on the as-cast ageing behavior of Al-11Si-0.35Mg alloy was investigated. It is shown that precipitation has been retarded in Sn containing alloy and more time is needed to reach its peak hardness,which is bigger than that of the base alloy. Analysis of the kinetic data shows that Sn addition does not change the growth dependent parameter n, but increases the nucleation density dependent parameter k. TEM results show that there are little precipitates in Sn containing alloy at the initial stage of as-cast ageing. However, the Sn addition increases the net density of precipitates during as-cast ageing, because there are many dislocation loops formed as ageing progresses and Sn segregated at the edges of dislocation loops, which acts as the nuclei of precipitates.

  8. Mechanical Behavior of Yttria-Stabilized Zirconia Aqueous Cast Tapes and Laminates

    Directory of Open Access Journals (Sweden)

    V. Moreno

    2014-01-01

    Full Text Available Aqueous tape casting was used to produce yttria-stabilized zirconia films for electrolyte-supported solid oxide fuel cell (SOFC. Tape casting slurries were prepared varying the binder content between 20 and 25 wt%. A commercial acrylic emulsion served as binder. Rheological measurements of the two slurries were performed. Both slurries showed a shear-thinning behavior. Tapes with 25 wt% binder exhibited adequate flexibility and a smooth and homogeneous surface, free of cracks and other defects. Suitable conditions of lamination were found and a theoretical density of 54% in the laminates was achieved. Laminated tapes showed higher tensile strength compared to single sheets. Tape orientation has a significant influence on the mechanical properties. Tensile strength, elongation to strain, and Young’s modulus measured in samples produced in the direction of casting showed higher property values.

  9. Influences of copper on solidification structure and hardening behavior of high chromium cast irons

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; XIONG Ji; FAN Hong-yuan; SHEN Bao-luo; GAO Sheng-ji

    2008-01-01

    The influences of copper on microstructure and the hardening behavior of high chromium cast irons subjected to sub-critical treatment were investigated.The results show that the mierostructure of the as-cast high chromium cast irons consists of retained austenite,martensite and M7 C3 type eutectic carbide.When copper is added into high chromium cast irons,austenite and carbide contents are increased.The increased addition of copper content from 0%to 1.84%leads to the increase of austenite and carbide from 15.9%and 20.0% to 61.0%and 35.5%,respectively.In the process of sub-critical treatment,the retained austenite in the matrix can be precipitated into secondary carbides and then transforms into martensite in cooling process,which causes the secondary hardening of the alloy under sub-critical treatment.High chromium cast irons containing copper in sub-critical treatment appear the second hardening curve peak due to the precipitation of copper from supersaturated matrix.

  10. Rheologic behaviors of A356 aluminum alloy billet produced by semisolid continuous casting process

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The experiments for rheologic behaviors of semisolid continuous casting billets of A356 alloy in semisolid state had been carried out with a rnultifunctional rheometer. The results show that the deformation rate increases with loading time, the maximum strain reaches to 120 % ( which is one time larger than that of traditional mold casting billet) and the strain can be rapidly elirninated to 10% after unloading. Moreover, there is a critic stress for billet deformation even in semisolid state, which is named as critic shear stress. This stress increases with the decreasing of heating time. The rheologic behaviors can be expressed by five elements mechanical model (H2 - [N1 | H2] - [N2|S] ) and can be modified with the increasing of heating time.

  11. Thermal fatigue behavior of cast superalloy Inconel 713LC

    Energy Technology Data Exchange (ETDEWEB)

    Mansuri, Mohammadreza; Hadavi, Seyed Mohammadmehdi; Zangeneh-Madar, Karim; Abaszade, Hasan; Zare, Esmail; Hejazi, Seyed Amir [MA University, Tehran (Iran, Islamic Republic of). Dept. of Materials Engineering

    2014-11-15

    The thermal fatigue behavior of superalloy Inconel 713LC was investigated at peak temperatures of 900, 1 000 and 1 100 C. Thermal fatigue tests were performed on self-constraint single-edge V-type notch specimens. The effect of the maximum temperature, T{sub max} in the thermal cycles on the crack characteristics was studied. Under identical test conditions a comparable crack propagation rate was observed for all three peak temperatures. The results showed that cycle numbers for crack initiation decreased while crack propagation rate increased with the increase in peak temperature. Therefore, it was concluded that in the current experimental conditions, thermal fatigue resistance reduced dramatically with the rise of upper temperature. Through optical microscopy and scanning electron microscopy observation, it was found that the primary cracks generally propagated along a preferential direction. Microstructure changes after thermal fatigue are also discussed on the basis of scanning electron microscopy observation.

  12. Characterization of Genomic Variants Associated with Scout and Recruit Behavioral Castes in Honey Bees Using Whole-Genome Sequencing.

    Science.gov (United States)

    Southey, Bruce R; Zhu, Ping; Carr-Markell, Morgan K; Liang, Zhengzheng S; Zayed, Amro; Li, Ruiqiang; Robinson, Gene E; Rodriguez-Zas, Sandra L

    2016-01-01

    Among forager honey bees, scouts seek new resources and return to the colony, enlisting recruits to collect these resources. Differentially expressed genes between these behaviors and genetic variability in scouting phenotypes have been reported. Whole-genome sequencing of 44 Apis mellifera scouts and recruits was undertaken to detect variants and further understand the genetic architecture underlying the behavioral differences between scouts and recruits. The median coverage depth in recruits and scouts was 10.01 and 10.7 X, respectively. Representation of bacterial species among the unmapped reads reflected a more diverse microbiome in scouts than recruits. Overall, 1,412,705 polymorphic positions were analyzed for associations with scouting behavior, and 212 significant (p-value 1000 bp apart from each other. A number of these variants were mapped to ncRNA LOC100578102, solute carrier family 12 member 6-like gene, and LOC100576965 (meprin and TRAF-C homology domain containing gene). Functional categories represented among the genes corresponding to significant variants included: neuronal function, exoskeleton, immune response, salivary gland development, and enzymatic food processing. These categories offer a glimpse into the molecular support to the behaviors of scouts and recruits. The level of association between genomic variants and scouting behavior observed in this study may be linked to the honey bee's genomic plasticity and fluidity of transition between castes. PMID:26784945

  13. Characterization of Genomic Variants Associated with Scout and Recruit Behavioral Castes in Honey Bees Using Whole-Genome Sequencing.

    Directory of Open Access Journals (Sweden)

    Bruce R Southey

    Full Text Available Among forager honey bees, scouts seek new resources and return to the colony, enlisting recruits to collect these resources. Differentially expressed genes between these behaviors and genetic variability in scouting phenotypes have been reported. Whole-genome sequencing of 44 Apis mellifera scouts and recruits was undertaken to detect variants and further understand the genetic architecture underlying the behavioral differences between scouts and recruits. The median coverage depth in recruits and scouts was 10.01 and 10.7 X, respectively. Representation of bacterial species among the unmapped reads reflected a more diverse microbiome in scouts than recruits. Overall, 1,412,705 polymorphic positions were analyzed for associations with scouting behavior, and 212 significant (p-value 1000 bp apart from each other. A number of these variants were mapped to ncRNA LOC100578102, solute carrier family 12 member 6-like gene, and LOC100576965 (meprin and TRAF-C homology domain containing gene. Functional categories represented among the genes corresponding to significant variants included: neuronal function, exoskeleton, immune response, salivary gland development, and enzymatic food processing. These categories offer a glimpse into the molecular support to the behaviors of scouts and recruits. The level of association between genomic variants and scouting behavior observed in this study may be linked to the honey bee's genomic plasticity and fluidity of transition between castes.

  14. Characterization of Genomic Variants Associated with Scout and Recruit Behavioral Castes in Honey Bees Using Whole-Genome Sequencing.

    Science.gov (United States)

    Southey, Bruce R; Zhu, Ping; Carr-Markell, Morgan K; Liang, Zhengzheng S; Zayed, Amro; Li, Ruiqiang; Robinson, Gene E; Rodriguez-Zas, Sandra L

    2016-01-01

    Among forager honey bees, scouts seek new resources and return to the colony, enlisting recruits to collect these resources. Differentially expressed genes between these behaviors and genetic variability in scouting phenotypes have been reported. Whole-genome sequencing of 44 Apis mellifera scouts and recruits was undertaken to detect variants and further understand the genetic architecture underlying the behavioral differences between scouts and recruits. The median coverage depth in recruits and scouts was 10.01 and 10.7 X, respectively. Representation of bacterial species among the unmapped reads reflected a more diverse microbiome in scouts than recruits. Overall, 1,412,705 polymorphic positions were analyzed for associations with scouting behavior, and 212 significant (p-value 1000 bp apart from each other. A number of these variants were mapped to ncRNA LOC100578102, solute carrier family 12 member 6-like gene, and LOC100576965 (meprin and TRAF-C homology domain containing gene). Functional categories represented among the genes corresponding to significant variants included: neuronal function, exoskeleton, immune response, salivary gland development, and enzymatic food processing. These categories offer a glimpse into the molecular support to the behaviors of scouts and recruits. The level of association between genomic variants and scouting behavior observed in this study may be linked to the honey bee's genomic plasticity and fluidity of transition between castes.

  15. Thermo-Mechanical Behavior of the Continuous Casting Bloom in the Heavy Reduction Process

    Science.gov (United States)

    Ji, Cheng; Wu, Chen-hui; Zhu, Miao-yong

    2016-08-01

    A two-stage sequential heavy reduction (HR) method, in which the reduction amount was increased both before and after the solidification end, is presented to simultaneously improve the homogeneity and compactness of the continuous casting bloom. With bearing steel GCr15 chosen as the specific research steel, a three-dimensional thermal-mechanical finite element model was developed to simulate and analyze the thermal and mechanical behaviors of the continuous casting bloom during the HR process. In order to ensure the accuracy of the simulation, the constitutive model parameters were derived from the experimental results. The predicted temperature distribution and shell thickness were verified using a thermal infrared camera and nail shooting results, respectively. The real measured relationship between the HR pressure and amount were applied to verify the mechanical model. The explorative application results showed that the quality of the bloom center and compactness of rolled bars have both been significantly improved after the HR was applied.

  16. Solid-particle erosion behavior of cast alloys used in the mining industry

    Institute of Scientific and Technical Information of China (English)

    Hakan Atapek; Sinan Fidan

    2015-01-01

    The erosive-wear response of five commercial ferrous-based cast alloys used for crushing was examined in this study. The micro-structures of the alloys were modified to elucidate the effect of microstructural features on wear. Erosion tests were conducted using alumi-num oxide particles (90–125 µm) at 70 m/s and a normal impact angle (90°). The worn surfaces were characterized by scanning electron mi-croscopy and 3D non-contact laser profilometry. It is found that (i) a pearlitic structure exhibiting a greater plastic deformation than both bainitic and martensitic structures shows the greatest resistance to erosive wear at normal impact and (ii) the fracture characteristics of car-bide and graphite particles plays an important role in determining the erosion wear behavior of the cast alloy matrices.

  17. AN INVESTIGATION OF DIFFERENTIAL REINFORCEMENT OF ALTERNATIVE BEHAVIOR WITHOUT EXTINCTION

    OpenAIRE

    Athens, Elizabeth S; Vollmer, Timothy R

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of each (Experiment 4), such that reinforcement favored appropriate behavior rather than problem behavior even though problem behavior still produced rei...

  18. Fabrication of sintered Zn-27%Al and comparison of its tribological behavior with cast alloy

    Institute of Scientific and Technical Information of China (English)

    倪东惠; 龙雁; 张大童; 罗宗强; 张文

    2002-01-01

    High quality Zn-base powder with low oxyg en content, fine particle s ize and fine microstructure can be obtained by gas atomization using nitrogen. C ast and sintered Zn-27%Al alloys (ZMJ) were prepared. Tribological behavior s of the cast and sintered alloys under lubricated and non-lubricated conditions were studied and compared. Worn surfaces and microstructures of these alloys wer e examined. Results indicate that although the strength of the sintered alloy is considerably less than that of the cast alloy, the sint ered alloy has a better wear resistance. The fine microstructure obtained by rap id solidification is beneficial to the wear-resisting property. The wear volume of sintered ZMJ is only 36% and 59% of the wear volume that found in cast ZMJ un der non-lubricated and lubricated conditions, respectively. For lubricated wear test, abrasive wear is the major wear mechanism and for non-lubricated wear tes t, oxidation wear and adhesive wear are the major wear mechanisms.

  19. Behavior of Non-metallic Inclusions in Centrifugal Induction Electroslag Castings

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    (para)In order to know the behavior of non-metallic inclusions in centrifugal induction electroslag castings (CIESC), non-metallic inclusions in 5CrMnMo and 4Cr5MoSiV1 were qualitatively and quantitatively analyzed. The largest size of inclusions in the casting and the thermodynamic possibility of TiN precipitation in steel were also calculated. The results show that sulfide inclusions are evenly distributed and the content is low. The amount of oxide inclusions in CIESC 4Cr5MoSiV1 steel is close to the ESR steel and lower than that in the EAF steel, and there are some differences along radial direction. Nitride inclusions are fine and the diameter of the largest one is 3~4um. With the increase of the centrifugal machine's rotational speed, the ratio of round inclusions increases and the ratio of sharp inclusions decreases. According to the experiment and the calculation results, it is pointed out that the largest diameter of non-metallic inclusions in the CIESC 4Cr5MoSiV1 casting is only 6.6mu, and [N%][Ti%] in 4Cr5MoSiV1 steel should be controlled less than 4.4~#U00d7tex010^{-5} in order to further reduce the amount and size of TiN inclusions.

  20. Influence of neodymium on high cycle fatigue behavior of die cast AZ91D magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    杨友; 李雪松

    2010-01-01

    High cycle fatigue behavior of die cast AZ91D magnesium alloy with different Nd contents was investigated.Axial mechanical fatigue tests were conducted at the stress ratio R=0.1 and the fatigue strength was evaluated using up-to-down load method on specimens of AZ91D with different Nd contents.The results showed that the grain of AZ91D alloy was refined,the size and amount of β-Mg17Al12 phase decreased and distributed uniformly with increasing Nd content.At the number of cycles to failure,Nf=107,the fatigue...

  1. Transformation Behavior and Microstructure in a 40Cr2Ni2MoV Cast Steel

    Institute of Scientific and Technical Information of China (English)

    Cheng Liu; Zhenbo Zhao; Sanjiwan. D. Bhole1; Derek O. Northwood

    2004-01-01

    The transformation behavior of a 40Cr2Ni2MoV cast steel manufactured by electroslag remelting (ESR) has been investigated. Compared to a forged steel, the incubation periods for both the pearlite and bainite transformations are shorter, but the transformation times are longer. The austenite is easier to transform into martensite. Optical microscopy and TEM indicated that there were variations in microstructure during the super-cooled austenite transformation. This is attributed to an inhomogeneous austenite, resulting from the segregation of elements during the ESR solidification.

  2. Study on the Thermal Fatigue Behavior of Hot Deformed Wear Resistance Cast Iron and Effect of Carbide

    Institute of Scientific and Technical Information of China (English)

    Dong Litao; Liu Rongchang; Li Xingyuan; Chen Xiuhong

    2007-01-01

    The thermal fatigue behavior of wear resistance cast iron with different quantity of deformation has been investigated. The results show that eutectic carbide is the main location and passage for initiation and extension of thermal fatigue cracks, approving that the more serious, the carbide breaks. The higher thermal fatigue resistance of wear resistance cast iron will be and thermal fatigue fracture belongs mainly to brittleness.

  3. Metadynamic Recrystallization Behavior of As-cast 904L Superaustenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Wei ZHANG; Jing ZHANG; Ying HAN; Rong LIU; De-ning ZOU; Guan-jun QIAO

    2016-01-01

    The metadynamic recrystallization (MDRX)behavior of as-cast 904L superaustenitic stainless steel was in-vestigated by double pass isothermal compression tests at temperatures of 950-1 150 ℃,strain rates of 0�05-5 s-1 and interval of 1-100 s.The effects of working parameters (deformation temperature,strain rate,pre-strain and in-terval time)on the flow curves and microstructural evolution were discussed.The MDRX fraction increased obvious-ly with the increase of deformation temperature,strain rate and interval time.The MDRX softening was controlled by the migration of grain boundary,annihilation of dislocation and dynamic recrystallization.Moreover,the kinetic model was established for the prediction of MDRX behavior of as-cast 904L superaustenitic stainless steel based on the experimental data.A good agreement between the predicted and the experimental values was achieved (correla-tion coefficient R2=0�98),indicating a satisfactory accuracy.

  4. Cancer cell differentiation heterogeneity and aggressive behavior in solid tumors

    OpenAIRE

    Jögi, Annika; Vaapil, Marica; Johansson, Martin; Påhlman, Sven

    2012-01-01

    The differentiation stage of tumors is a central aspect in the histopathological classification of solid malignancies. The differentiation stage is strongly associated with tumor behavior, and generally an immature tumor is more aggressive than the more differentiated counterpart. While this is common knowledge in surgical pathology, the contribution of differentiation-related gene expression and functions to tumor behavior is often overlooked in the experimental, tumor biological setting. Th...

  5. Effect of Casting Parameters on the Microstructural and Mechanical Behavior of Magnesium AZ31-B Alloy Strips Cast on a Single Belt Casting Simulator

    Directory of Open Access Journals (Sweden)

    Ahmad Changizi

    2014-01-01

    Full Text Available Strips of magnesium alloy AZ31-B were cast on a simulator of a horizontal single belt caster incorporating a moving mold system. Mixtures of CO2 and sulfur hexafluoride (SF6 gases were used as protective atmosphere during melting and casting. The castability of the AZ31-B strips was investigated for a smooth, low carbon steel substrate, and six copper substrates with various textures and roughnesses. Graphite powder was used to coat the substrates. The correlation between strip thickness and heat flux was investigated. It was found that the heat flux from the forming strip to the copper substrate was higher than that to the steel substrate, while coated substrates registered lower heat fluxes than uncoated substrates. The highest heat flux from the strip was recorded for casting on macrotextured copper substrates with 0.15 mm grooves. As the thickness of the strip decreased, the net heat flux decreased. As the heat flux increased, the grain sizes of the strips were reduced, and the SDAS decreased. The mechanical properties were improved when the heat flux increased. The black layers which formed on the strips’ surfaces were analyzed and identified as nanoscale MgO particles. Nano-Scale particles act as light traps and appeared black.

  6. Microstructure, tensile properties and fracture behavior of high temperature Al–Si–Mg–Cu cast alloys

    International Nuclear Information System (INIS)

    The high temperature tensile behavior of 354 aluminum cast alloy was investigated in the presence of Zr and Ni. The cast alloys were given a solutionizing treatment followed by artificial aging at 190 °C for 2 h. High temperature tensile tests were conducted at various temperatures from 25 °C to 300 °C. Optical microscopy and electron probe micro-analyzer were used to study the microstructure of different intermetallic phases formed. The fractographic observations of fracture surface were analyzed by scanning electron microscopy to understand the fracture mechanism. The results revealed that the intermetallics phases of (Al, Si)3(Zr, Ti), Al3CuNi and Al9NiFe are the main feature in the microstructures of alloys with Zr and Ni additions. The results also indicated that the tensile strength of alloy decreases with an increase in temperature. The combined addition of 0.2 wt% Zr and 0.2 wt% Ni leads to a 30% increase in the tensile properties at 300 °C compared to the base alloy. Zr and Ni bearing phases played a vital role in the fracture mechanism of the alloys studied

  7. Corrosion behavior of as-cast binary Mg-Bi alloys in Hank's solution

    Directory of Open Access Journals (Sweden)

    Wei-li Cheng

    2015-11-01

    Full Text Available Biodegradable Mg-xBi (x = 3, 6 and 9wt.% alloys were fabricated by ingot casting, and the change of corrosion behavior of the alloys in the Hank's solution was analyzed with respect to the microstructure using optical micrograph (OM, X-ray diffraction (XRD, scanning electron microscope (SEM equipped with an energy dispersive X-ray spectrometer (EDS, electrochemical and immersion tests. The results show that the microstructures of the as-cast Mg-Bi alloys mainly consisted of dendritic ?Mg grains and Mg3Bi2 phase in common, with the secondary dendrite arm spacing (SDAS decreasing significantly from 41.2 靘 to 25.4 靘 and the fraction of Mg3Bi2 increasing from 3.1% to 10.7%. Furthermore, the corrosion rate increasing from 1.32 mm昦-1 to 8.07 mm昦-1 as the Bi content was increased from 3wt.% to 9wt.%. The reduced corrosion resistance was mainly ascribed to the increasing fraction of the second phase particles, which bring positive effects on the development of pitting.

  8. Microstructure, tensile properties and fracture behavior of high temperature Al–Si–Mg–Cu cast alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, A.M.A., E-mail: madel@uqac.ca [Center for Advanced Materials, Qatar University, Doha (Qatar); Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez Canal University, Box 43721, Suez (Egypt); Samuel, F.H. [Université du Québec à Chicoutimi, Chicoutimi, QC, Canada G7H 2B1 (Canada); Al Kahtani, Saleh [Industrial Engineering Program, Mechanical Engineering Department, College of Engineering, Salman bin Abdulaziz University, Al Kharj (Saudi Arabia)

    2013-08-10

    The high temperature tensile behavior of 354 aluminum cast alloy was investigated in the presence of Zr and Ni. The cast alloys were given a solutionizing treatment followed by artificial aging at 190 °C for 2 h. High temperature tensile tests were conducted at various temperatures from 25 °C to 300 °C. Optical microscopy and electron probe micro-analyzer were used to study the microstructure of different intermetallic phases formed. The fractographic observations of fracture surface were analyzed by scanning electron microscopy to understand the fracture mechanism. The results revealed that the intermetallics phases of (Al, Si){sub 3}(Zr, Ti), Al{sub 3}CuNi and Al{sub 9}NiFe are the main feature in the microstructures of alloys with Zr and Ni additions. The results also indicated that the tensile strength of alloy decreases with an increase in temperature. The combined addition of 0.2 wt% Zr and 0.2 wt% Ni leads to a 30% increase in the tensile properties at 300 °C compared to the base alloy. Zr and Ni bearing phases played a vital role in the fracture mechanism of the alloys studied.

  9. Corrosion Behavior of AlSi10Mg Alloy Produced by Additive Manufacturing (AM vs. Its Counterpart Gravity Cast Alloy

    Directory of Open Access Journals (Sweden)

    Avi Leon

    2016-06-01

    Full Text Available The attractiveness of additive manufacturing (AM relates to the ability of this technology to rapidly produce very complex components at affordable costs. However, the properties and corrosion behavior, in particular, of products produced by AM technology should at least match the properties obtained by conventional technologies. The present study aims at evaluating the corrosion behavior and corrosion fatigue endurance of AlSi10Mg alloy produced by selective laser melting (SLM in comparison with its conventional counterpart, gravity cast alloy. The results obtained indicate that the corrosion resistance of the printed and cast alloys was relatively similar, with a minor advantage to the printed alloy. The corrosion fatigue endurance of the printed alloy was relatively improved compared to the cast alloy. This was mainly attributed to the significant differences between the microstructure and defect characteristics of those two alloys.

  10. Microstructure and elevated-temperature tensile properties of differential pressure sand cast Mg-4Y-3Nd-0.5Zr alloy

    Directory of Open Access Journals (Sweden)

    Hong-hui Liu

    2016-01-01

    Full Text Available The microstructures of an Mg-4Y-3Nd-0.5Zr alloy by differential pressure casting were investigated using scanning electron microscopy (SEM and transmission electron microscopy (TEM, and its tensile deformation behavior was measured using a Gleeble1500D themo-simulation machine in the temperature range of 200 to 400 °C at initial strain rates of 5×10-4 to 10-1 s-1. Results show that the as-cast microstructure consists of primary α-Mg phase and bone-shaped Mg5RE eutectic phase distributed along the grain boundary. The eutectic phase is dissolved into the matrix after solution treatment and subsequently precipitates during peak aging. Tensile deformation tests show that the strain rate has little effect on stress under 300 °C. Tensile stress decreases with an increase in temperature and the higher strain rate leads to an increase in stress above 300 °C. The fracture mechanism exhibits a mixed quasi-cleavage fracture at 200 °C, while the fracture above 300 °C is a ductile fracture. The dimples are melted at 400 °C with the lowest strain rate of 10-4 s-1.

  11. Caste and Choice: The Influence of Developmental Idealism on Marriage Behavior.

    Science.gov (United States)

    Allendorf, Keera; Thornton, Arland

    2015-07-01

    Is the marriage behavior of young people determined by their socioeconomic characteristics or their endorsement of developmental idealism? This article addresses this question using a unique longitudinal data set from Nepal and provides the first individual-level test of developmental idealism theory. The authors find that unmarried individuals with greater endorsement of developmental idealism in 2008 were more likely by 2012 to choose their own spouse, including a spouse of a different caste, rather than have an arranged marriage. Those with salaried work experience were also less likely to have arranged marriages, but urban proximity and education were not significant. The authors conclude that both developmental idealism and socioeconomic characteristics influence marriage and that their influences are largely independent. PMID:26430712

  12. Study on the hot corrosion behavior of a cast Ni-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Guo, J.T.; Zhang, J.; Yuan, C.; Zhou, L.Z.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

    2010-07-01

    Hot corrosion behavior of Nickel-base cast superalloy K447 in 90% Na{sub 2}SO{sub 4} + 10% NaCl melting salt at 850 C and 900 C was studied. The hot corrosion kinetic of the alloy follows parabolic rate law under the experimental conditions. The external layer is mainly Cr{sub 2}O{sub 3} scale which is protective to the alloy, the intermediate layer is the Ti-rich phase, and the internal layer is mainly the international oxides and sulfides. With increased corrosion time and temperature, the oxide scales are gradually dissolved in the molten salt and then precipitate as a thick and non-protective scale. Chlorides cause the formation of volatile species, which makes the oxide scale disintegrate and break off. The corrosion kinetics and morphology examinations tend to support the basic dissolution model for hot corrosion mechanisms. (orig.)

  13. Caste and Choice: The Influence of Developmental Idealism on Marriage Behavior.

    Science.gov (United States)

    Allendorf, Keera; Thornton, Arland

    2015-07-01

    Is the marriage behavior of young people determined by their socioeconomic characteristics or their endorsement of developmental idealism? This article addresses this question using a unique longitudinal data set from Nepal and provides the first individual-level test of developmental idealism theory. The authors find that unmarried individuals with greater endorsement of developmental idealism in 2008 were more likely by 2012 to choose their own spouse, including a spouse of a different caste, rather than have an arranged marriage. Those with salaried work experience were also less likely to have arranged marriages, but urban proximity and education were not significant. The authors conclude that both developmental idealism and socioeconomic characteristics influence marriage and that their influences are largely independent.

  14. High-temperature low cycle fatigue behavior of a gray cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Fan, K.L., E-mail: 12klfan@tongji.edu.cn; He, G.Q.; She, M.; Liu, X.S.; Lu, Q.; Yang, Y.; Tian, D.D.; Shen, Y.

    2014-12-15

    The strain controlled low cycle fatigue properties of the studied gray cast iron for engine cylinder blocks were investigated. At the same total strain amplitude, the low cycle fatigue life of the studied material at 523 K was higher than that at 423 K. The fatigue behavior of the studied material was characterized as cyclic softening at any given total strain amplitude (0.12%–0.24%), which was attributed to fatigue crack initiation and propagation. Moreover, this material exhibited asymmetric hysteresis loops due to the presence of the graphite lamellas. Transmission electron microscopy analysis suggested that cyclic softening was also caused by the interactions of dislocations at 423 K, such as cell structure in ferrite, whereas cyclic softening was related to subgrain boundaries and dislocation climbing at 523 K. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain amplitudes. It showed that the higher the temperature, the rougher the crack face of the examined gray cast iron at the same total strain amplitude. Additionally, the microcracks were readily blunted during growth inside the pearlite matrix at 423 K, whereas the microcracks could easily pass through pearlite matrix along with deflection at 523 K. The results of fatigue experiments consistently showed that fatigue damage for the studied material at 423 K was lower than that at 523 K under any given total strain amplitude. - Highlights: • The low cycle fatigue behavior of the HT250 for engine cylinder blocks was investigated. • TEM investigations were conducted to explain the cyclic deformation response. • The low cycle fatigue cracks of HT250 GCI were studied by SEM. • The fatigue life of the examined material at 523 K is higher than that at 423 K.

  15. High-temperature low cycle fatigue behavior of a gray cast iron

    International Nuclear Information System (INIS)

    The strain controlled low cycle fatigue properties of the studied gray cast iron for engine cylinder blocks were investigated. At the same total strain amplitude, the low cycle fatigue life of the studied material at 523 K was higher than that at 423 K. The fatigue behavior of the studied material was characterized as cyclic softening at any given total strain amplitude (0.12%–0.24%), which was attributed to fatigue crack initiation and propagation. Moreover, this material exhibited asymmetric hysteresis loops due to the presence of the graphite lamellas. Transmission electron microscopy analysis suggested that cyclic softening was also caused by the interactions of dislocations at 423 K, such as cell structure in ferrite, whereas cyclic softening was related to subgrain boundaries and dislocation climbing at 523 K. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain amplitudes. It showed that the higher the temperature, the rougher the crack face of the examined gray cast iron at the same total strain amplitude. Additionally, the microcracks were readily blunted during growth inside the pearlite matrix at 423 K, whereas the microcracks could easily pass through pearlite matrix along with deflection at 523 K. The results of fatigue experiments consistently showed that fatigue damage for the studied material at 423 K was lower than that at 523 K under any given total strain amplitude. - Highlights: • The low cycle fatigue behavior of the HT250 for engine cylinder blocks was investigated. • TEM investigations were conducted to explain the cyclic deformation response. • The low cycle fatigue cracks of HT250 GCI were studied by SEM. • The fatigue life of the examined material at 523 K is higher than that at 423 K

  16. The influence of surface condition on the metal dusting behavior of cast and wrought chromia forming alloys

    NARCIS (Netherlands)

    Hermse, C.G.M.; Asteman, H.; Ijzerman, R.M.; Jakobi, D.

    2013-01-01

    The current work investigated the impact of surface condition on the metal dusting behavior of chromia forming alloys. Five commercial alloys were included in the study, wrought 800H, 353MA, and cast G4859, G4852 Micro, and ET45 Micro, these alloys have a chromium and nickel content in the range of

  17. Research of quasi-solid fracture behavior of casting AI-4.5Cu alloys

    Directory of Open Access Journals (Sweden)

    Shengquan DONG

    2005-02-01

    Full Text Available The influencing mechanisms of elements Ti and Ce and their interactions on fracture behaviors of casting alloys AI-4.5Cu-0.6Mn were studied by observing tensile fracture behavior in quasi-solid zone under SEM and EDX instruments.The results indicate that the resistance stress against hot cracking can be improved obviously by addition of Ti, because of its grain refining function. It is also found that, when Ce is added into the alloys, besides its effect in refining crystalline, the mechanical behavior of lower melting point eutectic phase in quasi-solid zone can be improved efficiently by some compounds with Ce formed and deposited between dendrites. Therefore, a colligating effect of Ti and Ce on improving resistance stress against hot cracking is more efficient than that only single alloy element is applied. When hot cracking occurs, grains yield at first, and then crack spreads. Both inter-grain and trans-grain fractures are observed, but the major fracture manner is brittleness.

  18. Effect of Zr on behavior of compressive creep in as cast ZA27 alloy

    Institute of Scientific and Technical Information of China (English)

    魏晓伟; 沈保罗

    2003-01-01

    The effect of Zr on the behavior of compressive creep in as cast ZA27 alloy was investigated in the temperature range of 20-160 ℃ and under different compressive stresses in the range of 50-137.5 MPa with special apparatus. The results show that the primary compressive creep strains and steady creep rates of ZA27-Zr alloy and ZA27 alloy increase with increasing temperature and stress. However, the primary compressive creep strain and steady creep rate of the ZA27-Zr alloy are lower than that of the ZA27 alloy below 100 ℃, but higher at 160 ℃. The compressive creep behaviors in both ZA27-Zr alloy and ZA27 alloy obey an empirical equation lnt=C-nlnσ+Q/RT, and the exponent stress n is 3.63 for ZA27-Zr alloy and 3.46 for ZA27 alloy, respectively, the activation energy Q is 87.32 kJ/mol for ZA27-Zr alloy and 81.09 kJ/mol for ZA27 alloy. Different material structural constants are associated with different compressive creep behaviors in the alloy. The compressive creep rate in the alloy is controlled by the lattice diffusion of zinc and dislocation limb.

  19. Effects of processing variables on the creep behavior of investment cast Ti-48Al-2Nb-2Cr

    International Nuclear Information System (INIS)

    Intermetallics based on ordered γ-TiAl are being considered for the replacement of steels and nickel-based superalloys for high temperature aerospace and automotive applications. This study investigates the creep behavior of investment cast Ti-48Al-2Nb-2Cr with microstructures ranging from duplex to nearly lamellar. Constant load creep tests were conducted in air at temperatures of 650 C and 760 C and at stress levels of 104MPa, 155MPa, and 207MPa. The effects of cooling rates during casting, aluminum content, oxygen level, and microstructure on creep properties are discussed. The activation energy for creep and stress exponent are also reported

  20. An Investigation of Differential Reinforcement of Alternative Behavior without Extinction

    Science.gov (United States)

    Athens, Elizabeth S.; Vollmer, Timothy R.

    2010-01-01

    We manipulated relative reinforcement for problem behavior and appropriate behavior using differential reinforcement of alternative behavior (DRA) without an extinction component. Seven children with developmental disabilities participated. We manipulated duration (Experiment 1), quality (Experiment 2), delay (Experiment 3), or a combination of…

  1. Flow and thermal behavior of the top surface flux/powder layers in continuous casting molds

    Science.gov (United States)

    McDavid, R. M.; Thomas, B. G.

    1996-08-01

    Steady-state finite-element models have been formulated to investigate the coupled fluid flow and thermal behavior of the top-surface flux layers in continuous casting of steel slabs. The three-dimensional (3-D) FIDAP model includes the shear stresses imposed on the flux/steel interface by flow velocities calculated in the molten steel pool. It also includes different temperature-dependent powder properties for solidification and melting. Good agreement between the 3-D model and experimental measurements was obtained. The shear forces, imposed by the steel surface motion toward the submerged entry nozzle (SEN), create a large recirculation zone in the liquid flux pool. Its depth increases with increasing casting speed, increasing liquid flux conductivity, and decreasing flux viscosity. For typical conditions, this zone contains almost 4 kg of flux, which contributes to an average residence time of about 2 minutes. Additionally, because the shear forces produced by the narrowface consumption and the steel flow oppose each other, the flow in the liquid flux layer separates at a location centered 200 mm from the narrowface wall. This flow separation depletes the liquid flux pool at this location and may contribute to generically poor feeding of the mold-strand gap there. As a further consequence, a relatively cold spot develops at the wideface mold wall near the separation point. This nonuniformity in the temperature distribution may result in nonuniform heat removal, and possibly nonuniform initial shell growth in the meniscus region along the wideface off-corner region. In this way, potential steel quality problems may be linked to flow in the liquid flux pool.

  2. Tensile behavior of CF8-CPF8-304H and CF8M-CPF8M-316H stainless steel static and centrifugal castings

    Energy Technology Data Exchange (ETDEWEB)

    McEnerney, J.W.; Sikka, V.K.; Booker, M.K.

    1981-10-01

    We have analyzed the tensile behavior of 11 heats of grades CF8-CPF8-304H and 13 heats of grades CF8M-CPF8M-316H static and centrifugal castings from room temperature to 650/sup 0/C. Except for anomalous conditions, the centrifugal castings exhibited uniform composition. All CPF8-304H centrifugal castings contained only radial columnar grains, but some CPF8M-316H castings had columnar, banded, or equiaxed structures. Ultimate tensile strength and total elongation were the properties in which castings showed the most inferiority to wrought material. With increasing ferrite content, 0.2% yield strength and ultimate tensile strength increased while uniform elongation, total elongation, and reduction of area decreased. Although centrifugal castings did not exhibit significant end-to-end variation in tensile behavior, the 0.2% yield strength displayed anisotropy, with axial and circumferential values being greater than radial.

  3. Differential expressions of nuclear proteomes between honeybee (Apis mellifera L.) Queen and Worker Larvae: a deep insight into caste pathway decisions.

    Science.gov (United States)

    Begna, Desalegn; Han, Bin; Feng, Mao; Fang, Yu; Li, Jianke

    2012-02-01

    Honeybees (Apis mellifera L.) possess individuals (castes) in their colonies, to which specific tasks are allocated. Owing to a difference in nutrition, the young female larvae develop into either a fertile queen or a sterile worker. Despite a series of investigations on the underlying mechanisms of honeybee caste polyphenism, information on proteins and enzymes involved in DNA and RNA regulation in the nucleus is still missing. The techniques of nuclear protein enrichment, two-dimensional electrophoresis, mass spectrometry and bioinformatics were applied to understand the nuclear proteome changes in response to changes in environmental settings (nutrition and time) during the early developmental stages at the third (72 h), fourth (96 h), and fifth (120 h) instars of the two caste intended larvae. A total of 120 differentially expressed nuclear proteins were identified in both caste intended larvae during these developmental stages. The third, fourth and fifth instars of queen prospective larvae expressed 69%, 84%, and 68% of the proteins that had altered expression, respectively. Particularly, the prospective queen larvae up-regulated most of the proteins with nuclear functions. In general, this changing nuclear proteome of the two caste intended larvae over the three developmental stages suggests variations in DNA and RNA regulating proteins and enzymes. These variations of proteins and enzymes involved in DNA and RNA regulation in response to differential nutrition between the two caste intended larvae lead the two caste larvae to pursue different developmental trajectories. Hence, this first data set of the nuclear proteome helps us to explore the innermost biological makings of queen and worker bee castes as early as before the 72 h (3rd instar). Also, it provides new insights into the honeybee's polymorphism at nuclear proteome level and paves new ways to understand mechanisms of caste decision in other eusocial insects.

  4. Hot Corrosion Behavior of High-Chromium, High-Carbon Cast Irons in NaCl-KCl Molten Salts

    Directory of Open Access Journals (Sweden)

    S. Vuelvas-Rayo

    2012-01-01

    Full Text Available A study on the corrosion behavior of a series of experimental high-chromium (18.53–30.48 wt.%, high-carbon (3.82–5.17% cast irons in NaCl-KCl (1 : 1 M at 670°C has been evaluated by using weight loss technique and compared with a 304-type stainless steel. It was found that all castings had a higher corrosion rate than conventional 304SS and that the addition of Cr increased the degradation rate of the cast irons. Additionally, corrosion rate increased by increasing the C contents up to 4.29%, but it decreased with a further increase in its contents. Results are discussed in terms of consumption of the Cr2O3 layer by the melt.

  5. Sliding Wear Behavior of Plasma Sprayed Zirconia Coating on Cast Aluminum against Silicon Carbide Ceramic

    Institute of Scientific and Technical Information of China (English)

    Thuong-Hien LE; Young-Hun CHAE; Seock-Sam KIM

    2005-01-01

    The sliding wear behaviors of ZrO2-22 wt pct MgO (MZ) and ZrO2-8 wt pct Y2O3 (YZ) coatings deposited on a cast aluminum alloy with bond layer (NiCrCoAlY) by plasma spray were investigated under dry test conditions at room temperature. Under all load conditions, the wear mechanisms of the MZ and YZ coatings were almost the same.The material transfer and pullout were involved in the wear process of the studied coatings under the test conditions.The wear rate of the MZ coating was less than that of the YZ coating. While increasing the normal load, the wear rates of the MZ and YZ coatings increased. SEM was used to examine the worn surfaces and to elucidate likely wear mechanisms. Energy dispersive X-ray spectroscopy (EDX) analysis of the worn surfaces indicated that material transfer occurred in the direction from the SiC ball to the disk. Fracture toughness had a significant influence on the wear performance of the coatings. It was suggested that the material transfer played an important role in the wear behavior.

  6. Cracking behavior of thermally aged and irradiated CF-8 cast austenitic stainless steel

    Science.gov (United States)

    Chen, Y.; Alexandreanu, B.; Chen, W.-Y.; Natesan, K.; Li, Z.; Yang, Y.; Rao, A. S.

    2015-11-01

    To assess the combined effect of thermal aging and neutron irradiation on the cracking behavior of CF-8 cast austenitic stainless steel, crack growth rate (CGR) and fracture toughness J-R curve tests were carried out on compact-tension specimens in high-purity water with low dissolved oxygen. Both unaged and thermally aged specimens were irradiated at ∼320 °C to 0.08 dpa. Thermal aging at 400 °C for 10,000 h apparently had no effect on the corrosion fatigue and stress corrosion cracking behavior in the test environment. The cracking susceptibility of CF-8 was not elevated significantly by neutron irradiation at 0.08 dpa. Transgranular cleavage-like cracking was the main fracture mode during the CGR tests, and a brittle morphology of delta ferrite was often seen on the fracture surfaces at the end of CGR tests. The fracture toughness J-R curve tests showed that both thermal aging and neutron irradiation can induce significant embrittlement. The loss of fracture toughness due to neutron irradiation was more pronounced in the unaged than aged specimens. After neutron irradiation, the fracture toughness values of the unaged and aged specimens were reduced to a similar level. G-phase precipitates were observed in the aged and irradiated specimens with or without prior aging. The similar microstructural changes resulting from thermal aging and irradiation suggest a common microstructural mechanism of inducing embrittlement in CF-8.

  7. Effect of Carbon Properties on Melting Behavior of Mold Fluxes for Continuous Casting of Steels

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    During continuous casting of steel, the properties of mold fluxes strongly affect the casting performance,steel quality and environment of casting operation. The high temperature microscopy technique was used to investigate the melting behaviour of mold fluxes, and drip test method was used to determine their melting rate. The results showed that free carbon is a dominant factor in governing the melting behaviour of fluxes, and the melting rate is increased with increasing carbon reactivity and decreasing carbon content.

  8. Illumination controls dopaminergic differentiation regulating behavior

    OpenAIRE

    Dulcis, Davide; Spitzer, Nicholas C.

    2008-01-01

    Specification of the appropriate neurotransmitter is a crucial step in neuronal differentiation because it enables signaling among populations of neurons. Experimental manipulations demonstrate that both autonomous and activity-dependent genetic programs contribute to this process during development, but whether natural environmental stimuli specify transmitter expression in a neuronal population is unknown. We investigated neurons of the ventral suprachiasmatic nucleus that regulate neuroend...

  9. Casting fabrication of in situ Al3Ti-Al composites and their wear behaviors

    Institute of Scientific and Technical Information of China (English)

    Chen Tijun; Li Jian; Hao Yuan

    2009-01-01

    The Al3li intermetallic reinforced pure Al, Al-13Si and Al-17Cu matrix composites were prepared by casting method. Their microstructures and dry sliding wear behaviors at room temperature and 100℃ were particularly investigated. The results indicated that the Al3Ti phases in these composites were all in flaky form. But the aspect ratio of the Al3Ti platelets decreased with the increase of Ti content in the pure AI, Al-Cu and Al-Si matrix composites, in order of effectiveness. The effect of Si on the Al3Ti morphology seemed to be greater than that of Cu. The distributions of the Al3Ti platelets were different in the different matrix composites, leading to different grain refining effects. Except for the sub-wear regime of adhesive wear, the plastic deformation induced wear was a dominant wear mechanism for all of the composites at room temperature and 100℃. Increasing the testing temperature, decreasing the Al3Ti content or the hardness of materials could enhance these two wear mechanisms, and thus increase the wear rate. The Al-Cu matrix composite had the best wear resistance, while the pure Al matrix composite showed the worst for the same Ti content. These differences or changes were attributed to the differences in materials' hardness or the strengthening effects of the Al3Ti platelets.

  10. Vitellogenin underwent subfunctionalization to acquire caste and behavioral specific expression in the harvester ant Pogonomyrmex barbatus.

    Science.gov (United States)

    Corona, Miguel; Libbrecht, Romain; Wurm, Yannick; Riba-Grognuz, Oksana; Studer, Romain A; Keller, Laurent

    2013-01-01

    The reproductive ground plan hypothesis (RGPH) proposes that the physiological pathways regulating reproduction were co-opted to regulate worker division of labor. Support for this hypothesis in honeybees is provided by studies demonstrating that the reproductive potential of workers, assessed by the levels of vitellogenin (Vg), is linked to task performance. Interestingly, contrary to honeybees that have a single Vg ortholog and potentially fertile nurses, the genome of the harvester ant Pogonomyrmex barbatus harbors two Vg genes (Pb_Vg1 and Pb_Vg2) and nurses produce infertile trophic eggs. P. barbatus, thus, provides a unique model to investigate whether Vg duplication in ants was followed by subfunctionalization to acquire reproductive and non-reproductive functions and whether Vg reproductive function was co-opted to regulate behavior in sterile workers. To investigate these questions, we compared the expression patterns of P. barbatus Vg genes and analyzed the phylogenetic relationships and molecular evolution of Vg genes in ants. qRT-PCRs revealed that Pb_Vg1 is more highly expressed in queens compared to workers and in nurses compared to foragers. By contrast, the level of expression of Pb_Vg2 was higher in foragers than in nurses and queens. Phylogenetic analyses show that a first duplication of the ancestral Vg gene occurred after the divergence between the poneroid and formicoid clades and subsequent duplications occurred in the lineages leading to Solenopsis invicta, Linepithema humile and Acromyrmex echinatior. The initial duplication resulted in two Vg gene subfamilies preferentially expressed in queens and nurses (subfamily A) or in foraging workers (subfamily B). Finally, molecular evolution analyses show that the subfamily A experienced positive selection, while the subfamily B showed overall relaxation of purifying selection. Our results suggest that in P. barbatus the Vg gene underwent subfunctionalization after duplication to acquire caste- and

  11. Dynamic recrystallization behavior of an as-cast TiAl alloy during hot compression

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianbo, E-mail: lijianbo1205@163.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Liu, Yong, E-mail: yonliu@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Wang, Yan, E-mail: wangyan@csu.edu.cn [School of Aeronautics and Astronautics, Central South University, Changsha 410083 (China); Liu, Bin, E-mail: binetbin@gmail.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); He, Yuehui, E-mail: yuehui@mail.csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2014-11-15

    High temperature compressive deformation behaviors of as-cast Ti–43Al–4Nb–1.4W–0.6B alloy were investigated at temperatures ranging from 1050 °C to 1200 °C, and strain rates from 0.001 s{sup −1} to 1 s{sup −1}. Electron back scattered diffraction technique, scanning electron microscopy and transmission electron microscopy were employed to investigate the microstructural evolutions and nucleation mechanisms of the dynamic recrystallization. The results indicated that the true stress–true strain curves show a dynamic flow softening behavior. The dependence of the peak stress on the deformation temperature and the strain rate can well be expressed by a hyperbolic-sine type equation. The activation energy decreases with increasing the strain. The size of the dynamically recrystallized β grains decreases with increasing the value of the Zener–Hollomon parameter (Z). When the flow stress reaches a steady state, the size of β grains almost remains constant with increasing the deformation strain. The continuous dynamic recrystallization plays a dominant role in the deformation. In order to characterize the evolution of dynamic recrystallization volume fraction, the dynamic recrystallization kinetics was studied by Avrami-type equation. Besides, the role of β phase and the softening mechanism during the hot deformation was also discussed in details. - Highlights: • The size of DRXed β grains decreases with increasing the value of the Z. • The CDRX plays a dominant role in the deformation. • The broken TiB{sub 2} particles can promote the nucleation of DRX.

  12. Vitellogenin underwent subfunctionalization to acquire caste and behavioral specific expression in the harvester ant Pogonomyrmex barbatus.

    Directory of Open Access Journals (Sweden)

    Miguel Corona

    acquire caste- and behavior- specific expression associated with reproductive and non-reproductive functions, supporting the validity of the RGPH in ants.

  13. Dynamic Mechanical Behavior Characterization of Epoxy-Cast Al + Fe2O3 Thermite Mixture Composites

    Science.gov (United States)

    Ferranti, Louis; Thadhani, Naresh N.

    2007-11-01

    The dynamic mechanical behavior characterization of epoxy-cast stoichiometric mixtures of nano- or micron-scale aluminum and hematite (Fe2O3) powders is investigated in this work. Experiments conducted on rod-shaped samples, using instrumented reverse Taylor impact tests employing high-speed imaging and velocity interferometry, show that these composites exhibit viscoelastic deformation and brittle fracture behaviors. Upon impact, the samples display significant elastic and plastic deformation during both the loading and unloading stages, as determined from quantitative high-speed camera measurements of the transient deformation states. Approximately 50 pct elastic recovery of total axial strain was observed to occur rapidly (within tens of microseconds) after impact. A one-dimensional elastic-plastic wave propagation analysis was used for estimating the composite’s dynamic average yield stress and total plastic strain. The results reveal that the nano-Al + Fe2O3-containing epoxy composite is most resilient, has the highest strength, and is more capable of absorbing impact energy. The analysis additionally provides detailed information about elastic and plastic wave interactions for discrete times, up to the final state of the material. Calculations and observations through the coupling of high-speed camera images and velocity interferometry (VISAR) measurements show that the elastic recovery coincides with peak axial strain and the interaction of elastic and plastic waves propagating within the rod-shaped specimen. Hence, such an instrumented Taylor test provides a detailed view of the general wave structure within the material upon impact and, at the same time, enables a complete description of the stress-strain response.

  14. Effects of MC-Type Carbide Forming and Graphitizing Elements on Thermal Fatigue Behavior of Indefinite Chilled Cast Iron Rolls

    Science.gov (United States)

    Ahiale, Godwin Kwame; Choi, Won-Doo; Suh, Yongchan; Lee, Young-Kook; Oh, Yong-Jun

    2015-11-01

    The thermal fatigue behavior of indefinite chilled cast iron rolls with various V+Nb contents and Si/Cr ratios was evaluated. Increasing the ratio of Si/Cr prolonged the life of the rolls by reducing brittle cementites. Higher V+Nb addition also increased the life through the formation of carbides that refined and toughened the martensite matrix and reduced the thermal expansion mismatch in the microstructure.

  15. Environmental fatigue behaviors of wrought and cast stainless steels in 310 .deg. C Deoxygenated Water

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Pyung Yeon

    2011-02-15

    Environmental fatigue behaviors of wrought type 316LN stainless steel and cast CF8M stainless steel were investigated. LCF tests were performed at fixed strain rate of 0.04%/s with 0.4%, 0.6%, 0.8%, 1.0% strain amplitudes in 310 .deg. C deoxygenated water environment. In addition, to analyze microstructure effect on fatigue behavior, low cycle fatigue tests in air environment were performed at fixed strain rate of 0.4%/s, 0.04%/s with 0.4%, 0.8% strain amplitudes. It was shown that the low cycle fatigue life of CF8M in a 310 .deg. C deoxygenated water environment was slightly longer than that of 316LN. On the other hand, the low cycle fatigue life of CF8M in a 310 .deg. C air environment was slightly shorter than that of 316LN or was similar with that of 316LN. Through OM observation and phase image analysis, it was confirmed that the ferrite content of CF8M tested in a 310 .deg. C deoxygenated water environment was larger than that of CF8M tested in a 310 .deg. C air environment. It was shown that the ferrite phase fraction of CF8M tested in 310 .deg. C deoxygenated water environment was approximately 26∼28% and that of CF8M tested in air environment was approximately 10∼12%. The difference of ferrite content in CF8M results in superior tensile properties as higher ferrite content. Furthermore, the difference of ferrite content in CF8M might be the cause of different result of fatigue life between CF8M and 316LN depending on environment. In this study, focused on CF8M having 26∼28% ferrite content, to understand the causes of these differences in a 310 .deg. C deoxygenated water environment, fracture surface and crack morphology were observed. And material factors like microstructure, mechanical properties factors like stress behavior during fatigue life, factors by environmentally assisted cracking (EAC) like hydrogen induced cracking (HIC) and chemical compositions of both materials were analyzed. Mainly in a 310 .deg. C deoxygenated water environment, the

  16. Cancer cell differentiation heterogeneity and aggressive behavior in solid tumors.

    Science.gov (United States)

    Jögi, Annika; Vaapil, Marica; Johansson, Martin; Påhlman, Sven

    2012-05-01

    The differentiation stage of tumors is a central aspect in the histopathological classification of solid malignancies. The differentiation stage is strongly associated with tumor behavior, and generally an immature tumor is more aggressive than the more differentiated counterpart. While this is common knowledge in surgical pathology, the contribution of differentiation-related gene expression and functions to tumor behavior is often overlooked in the experimental, tumor biological setting. The mechanisms by which tumor cell differentiation stages are perturbed or affected are poorly explored but have recently come into focus with the introduction.of the tumor stem cell concept. While developmental biologists view the differentiation as a unidirectional event, pathologists and tumor biologists have introduced the concept of dedifferentiation to explain phenotypic changes occurring in solid tumors. In this review we discuss the impact of the tumor cell differentiation stage as used in surgical pathology. We further discuss knowledge gained from exploring the molecular basis of the differentiation and dedifferentiation processes in neuroblastoma and breast cancer, two tumor forms where the tumor cell differentiation concept is used in the clinical diagnostic work and where the tumor stem cell theory has been applied.

  17. Influence of submerged entry nozzle clogging on the behavior of molten steel in continuously cast slab molds

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The influence of submerged entry nozzle clogging on the behavior of molten steel in continuously cast slab molds was studied using commercial code CFX4.3. The results indicate that clogging at the top part of the nozzle port not only increases the velocity of molten steel, but also enhances the wall shear stress, F number and heat flux. This clogging has the greatest effect on the behavior of molten steel. However, clogging at the top 1/3 of the nozzle only increases the velocity of molten steel and has little influence. Clogging at the bottom of the nozzle almost has no influence.

  18. Mechanical behavior and microstructure of compressed Ti foams synthesized via freeze casting.

    Science.gov (United States)

    Jenei, Péter; Choi, Hyelim; Tóth, Adrián; Choe, Heeman; Gubicza, Jenő

    2016-10-01

    Pure Ti and Ti-5%W foams were prepared via freeze casting. The porosity and grain size of both the materials were 32-33% and 15-17µm, respectively. The mechanical behavior of the foams was investigated by uniaxial compression up to a plastic strain of ~0.26. The Young׳s moduli of both foams were ~23GPa, which was in good agreement with the value expected from their porosity. The Young׳s moduli of the foams were similar to the elastic modulus of cortical bones, thereby eliminating the osteoporosis-causing stress-shielding effect. The addition of W increased the yield strength from ~196MPa to ~235MPa. The microstructure evolution in the grains during compression was studied using electron backscatter diffraction (EBSD) and X-ray line profile analysis (XLPA). After compression up to a plastic strain of ~0.26, the average dislocation densities increased to ~3.4×10(14)m(-2) and ~5.9×10(14)m(-2) in the Ti and Ti-W foams, respectively. The higher dislocation density in the Ti-W foam can be attributed to the pinning effect of the solute tungsten atoms on dislocations. The experimentally measured yield strength was in good agreement with the strength calculated from the dislocation density and porosity. This study demonstrated that the addition of W to Ti foam is beneficial for biomedical applications, because the compressive yield strength increased while its Young׳s modulus remained similar to that of cortical bones. PMID:27469602

  19. Differential Effects of a Tier Two Behavior Intervention Based on Function of Problem Behavior

    Science.gov (United States)

    McIntosh, Kent; Campbell, Amy L.; Carter, Deborah Russell; Dickey, Celeste Rossetto

    2009-01-01

    The purpose of this study was to investigate the effectiveness of a tier two daily behavior card intervention and differential effects based on function of problem behavior. The participants were 36 elementary school students nominated for additional intervention beyond universal School-Wide Positive Behavior Support. Measures included…

  20. Hormonal influences on sexually differentiated behavior in nonhuman primates.

    Science.gov (United States)

    Wallen, Kim

    2005-04-01

    Sexually dimorphic behavior in nonhuman primates results from behavioral predispositions organized by prenatal androgens. The rhesus monkey has been the primary primate model for understanding the hormonal organization of sexually dimorphic behavior. Historically, female fetuses have received high prenatal androgen doses to investigate the masculinizing and defeminizing effects of androgens. Such treatments masculinized juvenile and adult copulatory behavior and defeminized female-typical sexual initiation to adult estrogen treatment. Testosterone and the nonaromatizable androgen, 5alpha-dihydrotestosterone, produced similar effects suggesting that estrogenic metabolites of androgens are not critical for masculinization and defeminization in rhesus monkeys. Long duration androgen treatments masculinized both behavior and genitalia suggesting that socializing responses to the females' male-like appearance may have produced the behavioral changes. Treatments limited to 35 days early or late in gestation differentially affected behavioral and genital masculinization demonstrating direct organizing actions of prenatal androgens. Recent studies exposed fetal females to smaller doses of androgens and interfered with endogenous androgens using the anti-androgen flutamide. Low dose androgen treatment only significantly masculinized infant vocalizations and produced no behavioral defeminization. Females receiving late gestation flutamide showed masculinized infant vocalizations and defeminized interest in infants. Both late androgen and flutamide treatment hypermasculinized some male juvenile behaviors. Early flutamide treatment blocked full male genital masculinization, but did not alter their juvenile or adult behavior. The role of neuroendocrine feedback mechanisms in the flutamide effects is discussed. Sexually differentiated behavior ultimately reflects both hormonally organized behavioral predispositions and the social experience that converts these predispositions

  1. Mechanical properties and constitutive behaviors of as-cast 7050 aluminum alloy from room temperature to above the solidus temperature

    Science.gov (United States)

    Bai, Qing-ling; Li, Hong-xiang; Du, Qiang; Zhang, Ji-shan; Zhuang, Lin-zhong

    2016-08-01

    The mechanical properties and constitutive behaviors of as-cast AA7050 in both the solid and semi-solid states were determined using the on-cooling and in situ solidification approaches, respectively. The results show that the strength in the solid state tends to increase with decreasing temperature. The strain rate plays an important role in the stress-strain behaviors at higher temperatures, whereas the influence becomes less pronounced and irregular when the temperature is less than 250°C. The experimental data were fitted to the extended Ludwik equation, which is suitable to describe the mechanical behavior of the materials in the as-cast state. In the semi-solid state, both the strength and ductility of the alloy are high near the solidus temperature and decrease drastically with decreasing solid fraction. As the solid fraction is less than 0.97, the maximum strength only slightly decreases, whereas the post-peak ductility begins to increase. The experimental data were fitted to the modified creep law, which is used to describe the mechanical behavior of semi-solid materials, to determine the equivalent parameter f GBWL, i.e., the fraction of grain boundaries covered by liquid phase.

  2. A coupled analysis of fluid flow, heat transfer and deformation behavior of solidifying shell in continuously cast beam blank

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Eui; Yeo, Tae Jung; Oh, Kyu Hwan; Yoon, Jong Kyu [School of Materials Science and Engineering, Seoul Nat`l Univ., Seoul (Korea, Republic of); Han, Heung Nam [Oxford Center for Advanced Materials and Composites, Department of Materials, Univ. of Oxford (United Kingdom)

    1997-12-31

    A mathematical model for a coupled analysis of fluid flow, heat transfer and deformation behavior in the continuously cast beam blank has been developed. The fluid flow, heat transfer and solidification in the mold region were analyzed with 3-dimensional finite difference method (FDM) based on control volume method. A body fitted coordinate system was introduced for the complex geometry of the beam blank. The effects of turbulence and natural convection of molten steel were taken into account in determining the fluid flow in the strand. The thermo-elasto-plastic deformation behavior in the cast strand and the formation of air gap between the solidifying shell and the mold were analyzed by the finite element method (FEM) using the 2-dimensional slice temperature profile calculated by the FDM. The heat flow between the strand and the mold was evaluated by the coupled analysis between the fluid flow-heat transfer analysis and the thermo-elasto-plastic stress analysis. In order to determine the solid fraction in the mushy zone, the microsegregation of solute element was assessed. The effects of fluid flow on the heat transfer, the solidification of steel and the distribution of shell thickness during the casting of the beam blank were simulated. The deformation behavior of the solidifying shell and the possibility of cracking of the strand were also investigated. The recirculating flows were developed in the regions of the web and the flange tip. The impinging of the inlet flow from the nozzle retarded the growing of solidifying shell in the regions of the fillet and the flange. The air gap between the strand and the mold was formed near the region of the corner of the flange tip. At the initial stage of casting, the probability of the surface cracking was high in the regions of the fillet and the flange tip. After the middle stage of casting, the internal cracking was predicted in the regions of the flange tip, and between the fillet and the flange tip. (author) 38

  3. Modeling of the interface behavior in tape casting of functionally graded ceramics for magnetic refrigeration parts

    DEFF Research Database (Denmark)

    Jabbari, Masoud; Spangenberg, Jon; Hattel, Jesper Henri

    2013-01-01

    The main goal of this work is to study the multiple material flows in side-by-side (SBS) tape casting and analyze the influence of the different material properties, i.e. the density and the viscosity, on the interface between the fluids, since this is highly important for the efficiency of a gra......The main goal of this work is to study the multiple material flows in side-by-side (SBS) tape casting and analyze the influence of the different material properties, i.e. the density and the viscosity, on the interface between the fluids, since this is highly important for the efficiency...

  4. Differentiating Behaviors among Spillane's Forms of Distributed Leadership

    Science.gov (United States)

    Zirkle, Laura

    2012-01-01

    The purpose of this study was to identify what leadership behaviors are associated with each of Spillane's (2006) three conceptually distinct forms of distributed leadership, and to determine whether specific influence tactics (Yukl, Seifert & Chavez, 2008) are differentially associated with each form. A two-phased, mixed methods design was…

  5. 蜜蜂级型分化研究的进展%Research Progress on the Caste Differentiation in the Honeybee

    Institute of Scientific and Technical Information of China (English)

    沈芳; 殷玲; 刘振国; 沈杰; 吉挺

    2013-01-01

    Caste differentiation is the foundation of researches on bee eusocial biology. This review focuses on research progresses of bee caste differentiation, the contribution of nutrition, hormones, DNA methylation, differential expressed proteomics and genomics, cell size and histone deacetylase inhibitor activity to bee caste differentiation, and the interactions of those factors. Accordingly, the problems in recent researches and prospects for future researches on bee caste differentiation were put forward.%级型分化是蜜蜂生物学研究的基础。本研究总结了前人在蜜蜂级型分化的研究进展:营养与级型分化的关系;激素与级型分化的关系;DNA甲基化与级型分化的关系;基因组和蛋白质组的差异表达与级型分化的关系;蜂房大小和组蛋白去乙酰酶与级型分化的关系。这些研究结果表明:蜜蜂的级型分化的调节是一个非常复杂的过程,是很多因素共同调节的结果。据此提出关于蜜蜂级型分化研究存在的一些问题,并对以后的研究进行了展望。

  6. Effect of N addition on tensile and corrosion behaviors of CD4MCU cast duplex stainless steels

    Science.gov (United States)

    Son, Jinil; Kim, Sangshik; Lee, Jehyun; Choi, Byunghak

    2003-08-01

    The effect of N addition on the microstructure, tensile, and corrosion behaviors of CD4MCU (Fe-25Cr-5Ni-2.8Cu-2Mo) cast duplex stainless steel was examined in the present study. The slow strain rate tests were also conducted at a nominal strain rate of 1 × 10-6/s in air and 3.5 pct NaCl+5 pct H2SO4 solution for studying the stress corrosion cracking (SCC) behavior. It was observed that the volume fraction of austenitic phase in CD4MCU alloy varied from 38 to 59 pct with increasing nitrogen content from 0 to 0.27 wt. pct. The tensile behavior of CD4MCU cast duplex stainless steels, which tended to vary significantly with different N contents, appeared to be strongly related to the volume changes in ferritic and austenitic phases, rather than the intrinsic N effect. The improvement in the resistance to general corrosion in 3.5 pct NaCl+5 pct H2SO4 aqueous solution was notable with 0.13 pct N addition. The further improvement was not significant with further N addition. The resistance to SCC of CD4MCU cast duplex stainless steels in 3.5 pct NaCl+5 pct H2SO4 aqueous solution, however, increased continuously with increasing N content. The enhancement in the SCC resistance was believed to be related to the volume fraction of globular austenitic colonies, which tended to act as barriers for the development of initial pitting cracks in the ferritic phase into the sharp ones.

  7. Nonneural Androgen Receptors Affect Sexual Differentiation of Brain and Behavior.

    Science.gov (United States)

    Swift-Gallant, Ashlyn; Coome, Lindsay A; Ramzan, Firyal; Monks, D Ashley

    2016-02-01

    Testosterone, acting via estrogenic and androgenic pathways, is the major endocrine mechanism promoting sexual differentiation of the mammalian nervous system and behavior, but we have an incomplete knowledge of which cells and tissues mediate these effects. To distinguish between neural and nonneural actions of androgens in sexual differentiation of brain and behavior, we generated a loxP-based transgenic mouse, which overexpresses androgen receptors (ARs) when activated by Cre. We used this transgene to overexpress AR globally in all tissues using a cytomegalovirus (CMV)-Cre driver (CMV-AR), and we used a Nestin-Cre driver to overexpress AR only in neural tissue (Nes-AR). We then examined whether neural or global AR overexpression can affect socio-sexual behaviors using a resident-intruder paradigm. We found that both neural and global AR overexpression resulted in decreased aggressive behaviors and increased thrusting during mounting of intruders, consistent with a neural site of action. Global, but not neural, AR overexpression in males led to an increase in same-sex anogenital investigation. Together, these results suggest novel roles for nonneural AR in sexual differentiation of mice, and indicate that excess AR can lead to a paradoxical reduction of male-typical behavior. PMID:26636184

  8. Analysis of Solid-Liquid Interface Behavior during Continuous Strip-Casting Process Using Sharp-Interface Technique

    Directory of Open Access Journals (Sweden)

    Changbum Lee

    2013-01-01

    Full Text Available Continuous strip casting (CSC has been developed to fabricate thin metal plates while simultaneously controlling the microstructure of the product. A numerical analysis to understand the solid-liquid interface behaviors during CSC was carried out and used to identify the solidification morphologies of the plate, which were then used to obtain the optimum process conditions. In this study, we used a modified level contour reconstruction method and the sharp-interface method to modify the interface tracking, and we performed a simulation analysis to identify the differences in the material properties that affect the interface behavior. The effects of the process parameters such as the heat transfer coefficient and extrusion velocity on the behavior of the solid-liquid interface are estimated and also used to improve the CSC process.

  9. CYCLIC PLASTIC BEHAVIOR AND FATGIUE LIFE OF AZ91 ALLOY IN AS-CAST AND ULTRAFINE-GRAINED STATE

    Directory of Open Access Journals (Sweden)

    Stanislava Fintová

    2014-06-01

    Full Text Available Fatigue properties of magnesium alloy AZ91 in as-cast and in ultrafine-grained state prepared by equal channel angular pressing were investigated. The fatigue strength in the low-cycle fatigue region was found to be substantially improved by the severe plastic deformation, whereas the improvement in the high-cycle fatigue region is negligible. The cyclic plastic response in both states is qualitatively similar; short initial softening is followed by a long cyclic hardening. The observed fatigue behavior was discussed in terms of specific microstructural features of both states and on the basis of cyclic slip localization and fatigue crack initiation. 

  10. Dimorphic ovary differentiation in honeybee (Apis mellifera) larvae involves caste-specific expression of homologs of ark and buffy cell death genes.

    Science.gov (United States)

    Dallacqua, Rodrigo Pires; Bitondi, Márcia Maria Gentile

    2014-01-01

    The establishment of the number of repeated structural units, the ovarioles, in the ovaries is one of the critical events that shape caste polyphenism in social insects. In early postembryonic development, honeybee (Apis mellifera) larvae have a pair of ovaries, each one consisting of almost two hundred ovariole primordia. While practically all these ovarioles continue developing in queen-destined larvae, they undergo massive programmed cell death (PCD) in worker-destined larvae. So as to gain insight into the molecular basis of this fundamental process in caste differentiation we used quantitative PCR (qPCR) and fluorescent in situ hybridization (FISH) to investigate the expression of the Amark and Ambuffy genes in the ovaries of the two honeybee castes throughout the fifth larval instar. These are the homologs of ark and buffy Drosophila melanogaster genes, respectively, involved in activating and inhibiting PCD. Caste-specific expression patterns were found during this time-window defining ovariole number. Amark transcript levels were increased when ovariole resorption was intensified in workers, but remained at low levels in queen ovaries. The transcripts were mainly localized at the apical end of all the worker ovarioles, but appeared in only a few queen ovarioles, thus strongly suggesting a function in mediating massive ovariolar cell death in worker larvae. Ambuffy was mainly expressed in the peritoneal sheath cells covering each ovariole. The levels of Ambuffy transcripts increased earlier in the developing ovaries of queens than in workers. Consistent with a protective role against cell death, Ambuffy transcripts were localized in practically all queen ovarioles, but only in few worker ovarioles. The results are indicative of a functional relationship between the expression of evolutionary conserved cell death genes and the morphological events leading to caste-specific ovary differentiation in a social insect.

  11. Dimorphic ovary differentiation in honeybee (Apis mellifera larvae involves caste-specific expression of homologs of ark and buffy cell death genes.

    Directory of Open Access Journals (Sweden)

    Rodrigo Pires Dallacqua

    Full Text Available The establishment of the number of repeated structural units, the ovarioles, in the ovaries is one of the critical events that shape caste polyphenism in social insects. In early postembryonic development, honeybee (Apis mellifera larvae have a pair of ovaries, each one consisting of almost two hundred ovariole primordia. While practically all these ovarioles continue developing in queen-destined larvae, they undergo massive programmed cell death (PCD in worker-destined larvae. So as to gain insight into the molecular basis of this fundamental process in caste differentiation we used quantitative PCR (qPCR and fluorescent in situ hybridization (FISH to investigate the expression of the Amark and Ambuffy genes in the ovaries of the two honeybee castes throughout the fifth larval instar. These are the homologs of ark and buffy Drosophila melanogaster genes, respectively, involved in activating and inhibiting PCD. Caste-specific expression patterns were found during this time-window defining ovariole number. Amark transcript levels were increased when ovariole resorption was intensified in workers, but remained at low levels in queen ovaries. The transcripts were mainly localized at the apical end of all the worker ovarioles, but appeared in only a few queen ovarioles, thus strongly suggesting a function in mediating massive ovariolar cell death in worker larvae. Ambuffy was mainly expressed in the peritoneal sheath cells covering each ovariole. The levels of Ambuffy transcripts increased earlier in the developing ovaries of queens than in workers. Consistent with a protective role against cell death, Ambuffy transcripts were localized in practically all queen ovarioles, but only in few worker ovarioles. The results are indicative of a functional relationship between the expression of evolutionary conserved cell death genes and the morphological events leading to caste-specific ovary differentiation in a social insect.

  12. An investigation of fracture and fatigue crack growth behavior of cast niobium aluminide intermetallics

    Energy Technology Data Exchange (ETDEWEB)

    Ye, F.; Soboyejo, W.O. [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering; Farkas, D. [Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 213 Holden Hall, Blacksburg, VA 24061-0237 (United States)

    1999-05-31

    This paper presents the results of a combined experimental and theoretical study of fracture toughness and fatigue crack growth in cast Nb-15Al-xTi (x=10, 25 and 40 at%) niobium aluminide-based intermetallics. Fracture toughness and fatigue crack growth resistance are shown to improve significantly in the cast alloy containing 40 at% Ti. The improvements in the fracture toughness of the 40Ti alloy are shown to be due to the combined effects of ligament toughening, crack-tip plasticity and crack-tip blunting. The atomistic simulations show that the increased plasticity in these alloys is associated with their higher Ti content. The micromechanisms of fatigue crack growth are also elucidated. The implications of the results are discussed for potential structural application of niobium aluminide intermetallics. (orig.) 19 refs.

  13. Molecular cloning and characterization of juvenile hormone acid methyltransferase in the honey bee, Apis mellifera, and its differential expression during caste differentiation.

    Science.gov (United States)

    Li, Wenfeng; Huang, Zachary Y; Liu, Fang; Li, Zhiguo; Yan, Limin; Zhang, Shaowu; Chen, Shenglu; Zhong, Boxiong; Su, Songkun

    2013-01-01

    Juvenile hormone acid methyltransferase (JHAMT) is an enzyme involved in one of the final steps of juvenile hormone biosynthesis in insects. It transfers a methyl group from S-adenosyl-L-methionine (SAM) to the carboxyl group of either farnesoic acid (FA) or JH acid (JHA). Several genes coding for JHAMT have been cloned and characterized from insects from different orders, and they have been shown to play critical roles in metamorphosis and reproduction. However, the significance of JHAMT in Hymenopteran insects is unknown. We used RACE amplification method to clone JHAMT cDNA from the honey bee, Apis mellifera (AmJHAMT). The full length cDNA of AmJHAMT that we cloned is 1253bp long and encodes a 278-aa protein that shares 32-36% identity with known JHAMTs. A SAM-binding motif, conserved in the SAM-dependent methyltransferase (SAM-MT) superfamily, is present in AmJHAMT. Its secondary structure also contains a typical SAM-MT fold. Most of the active sites bound with SAM and substrates (JHA or FA) are conserved in AmJHAMT as in other JHAMT orthologs. Phylogenetic analysis clustered AmJHAMT with the other orthologs from Hymenoptera to form a major clade in the phylogenetic tree. Purified recombinant AmJHAMT protein expressed in E. coli was used to produce polyclonal antibodies and to verify the identity of AmJHAMT by immunoblotting and mass spectrometry. Quantitative RT-PCR and immunoblotting analyses revealed that queen larvae contained significantly higher levels of AmJHAMT mRNA and protein than worker larvae during the periods of caste development. The temporal profiles of both AmJHAMT mRNA and protein in queens and workers showed a similar pattern as the JH biosynthesis. These results suggest that the gene that we cloned codes for a functional JHAMT that catalyzes the final reactions of JH biosynthesis in honey bees. In addition, AmJHAMT may play an important role in honey bee caste differentiation. PMID:23874662

  14. Molecular cloning and characterization of juvenile hormone acid methyltransferase in the honey bee, Apis mellifera, and its differential expression during caste differentiation.

    Directory of Open Access Journals (Sweden)

    Wenfeng Li

    Full Text Available Juvenile hormone acid methyltransferase (JHAMT is an enzyme involved in one of the final steps of juvenile hormone biosynthesis in insects. It transfers a methyl group from S-adenosyl-L-methionine (SAM to the carboxyl group of either farnesoic acid (FA or JH acid (JHA. Several genes coding for JHAMT have been cloned and characterized from insects from different orders, and they have been shown to play critical roles in metamorphosis and reproduction. However, the significance of JHAMT in Hymenopteran insects is unknown. We used RACE amplification method to clone JHAMT cDNA from the honey bee, Apis mellifera (AmJHAMT. The full length cDNA of AmJHAMT that we cloned is 1253bp long and encodes a 278-aa protein that shares 32-36% identity with known JHAMTs. A SAM-binding motif, conserved in the SAM-dependent methyltransferase (SAM-MT superfamily, is present in AmJHAMT. Its secondary structure also contains a typical SAM-MT fold. Most of the active sites bound with SAM and substrates (JHA or FA are conserved in AmJHAMT as in other JHAMT orthologs. Phylogenetic analysis clustered AmJHAMT with the other orthologs from Hymenoptera to form a major clade in the phylogenetic tree. Purified recombinant AmJHAMT protein expressed in E. coli was used to produce polyclonal antibodies and to verify the identity of AmJHAMT by immunoblotting and mass spectrometry. Quantitative RT-PCR and immunoblotting analyses revealed that queen larvae contained significantly higher levels of AmJHAMT mRNA and protein than worker larvae during the periods of caste development. The temporal profiles of both AmJHAMT mRNA and protein in queens and workers showed a similar pattern as the JH biosynthesis. These results suggest that the gene that we cloned codes for a functional JHAMT that catalyzes the final reactions of JH biosynthesis in honey bees. In addition, AmJHAMT may play an important role in honey bee caste differentiation.

  15. Study on fragmentation and dissolution behavior of carbide in a hot-rolled hypereutectic high chromium cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei; Jiang, Yehua, E-mail: jiangyehua@kmust.edu.cn; Xiao, Han; Tan, Jun

    2015-01-05

    Highlights: • The method to prepare Carbon steel/High chromium iron is totally new. • High chromium iron can achieve small plastic deformation during hot rolling process. • Carbides in high chromium irons are crushed, refined obviously and becoming isolated, which is benefit to improve the impact toughness. • The carbide fragmentation and dissolution behavior of the hot-rolled HCCI were analyzed. - Abstract: A sandwich-structured composite containing a hypereutectic high chromium cast iron (HCCI) and low carbon steel (LCS) claddings was newly fabricated by centrifugal casting, then the blank was hot-rolled into composite plate. The carbide fragmentation and dissolution behavior of the hot-rolled HCCI were analyzed. During hot rolling, significant refinement of carbides was discovered in hot-rolled HCCI specimens. The carbides were broken and partly dissolved into the austenite matrix. The results show that carbides are firstly dissolved under the action of stress. There are grooves appeared at the boundaries of the carbides. The grooves reduce the cross section of the carbide. When the cross section of the carbide reaches to the required minimum critical cross section, the carbide breaks through the tensile force. After break, carbides continue to dissolve since more interfaces between the matrix and carbides are generated. The secondary carbides precipitated due to the dissolution are index as fcc and stacking faults parallel to the {1 1 1} are observed.

  16. Sexual Differentiation of Behavior in Monkeys: Role of Prenatal Hormones

    OpenAIRE

    Wallen, Kim; Hassett, Janice M.

    2009-01-01

    The theoretical debate over the relative contributions of nature and nurture to sexual differentiation of behavior has increasingly moved towards an interactionist explanation requiring both influences. In practice, however, nature and nurture have often been seen as separable, influencing human clinical sex assignment decisions, sometimes with disastrous consequences. Decisions about sex assignment of children born with intersex conditions have been based almost exclusively on the appearance...

  17. Behavioral Differentiation and Ovarian Development of Unmated Gynes, Queens, and Workers of Ectatomma vizottoi Almeida 1987 (Formicidae, Ectatomminae

    Directory of Open Access Journals (Sweden)

    Alexsandro Santana Vieira

    2012-01-01

    Full Text Available Behavioral differentiation and ovarian development of unmated gynes, queens, and workers of Ectatomma vizottoi were investigated in laboratory conditions. Forty-one behavioral acts were identified and quantified for workers, 19 for queens and 24 for unmated gynes, for an overall species repertoire of 42 different behavioral acts. Ovipositing reproductive eggs was an exclusive task of the queen, whereas workers showed 15 caste-specific behaviors. The most important (frequent behaviors for the queens were brood care, immobility, and reproduction, and for workers were immobility, grooming/interaction, brood care, and foraging. Unmated gynes (not winged primarily showed immobility, brood care, grooming/interaction, and foraging. Analysis of ovarian development showed that unmated gynes had little-developed ovarioles, in contrast to queens. Queens and unmated gynes showed a clear behavioral differentiation, in which queens played the role of reproducers and unmated gynes performed activities belonging to the worker repertoire. Despite the presence of several breeding queens in the colony, functional monogyny was the rule.

  18. Temperature effects on the static and dynamic fracture behaviors of low-silicon CA-15 tempered stainless steel castings

    Science.gov (United States)

    Hsu, Cheng-Hsun; Teng, Hwei-Yuan

    2005-04-01

    In this research we studied the effect of testing temperature on both static and dynamic fracturing behaviors of low-silicon CA-15 martensitic stainless steel (MSS) castings after austenitizing and tempering treatments. The results showed that the material's microstructure was influenced by heat treatment and various testing temperatures would cause different fracturing mechanisms. In static tensile tests, the 573-673 K tempered specimens occurred secondary strengthening at 423 K and 298 K testing temperatures. However, there is a contrast of weakening occurred at 123 K for the same type of tempered samples. The phenomenon was mainly triggered by local cracking at the ferrite/martensitic interface and incoherent precipitate site in the materials because of the existence of shrinkage stress under subzero temperature. In the dynamic strain-rate tests, impact embrittlement occurred in the 573-673 K tempered samples as a result of the tempered martensite embrittlement (TME) phenomenon. The ductile-to-brittle transition temperature (DBTT) of the tempered material was obviously lower than that of the as-cast material. Also, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were performed to correlate the properties attained to the microstructural observation.

  19. Every child is different : differential parental treatment and adolescent problem behavior

    NARCIS (Netherlands)

    Tamrouti-Makkink, Ilse Diana

    2006-01-01

    This dissertation is an important contribution to the research on differential parental treatment and adolescent problem behavior. First, it extends earlier studies by exploring possible moderating factors explaining the level of differential parental treatment and the link between differential pare

  20. Characterization of Genomic Variants Associated with Scout and Recruit Behavioral Castes in Honey Bees Using Whole-Genome Sequencing

    OpenAIRE

    Southey, Bruce R.; Ping Zhu; Carr-Markell, Morgan K.; Liang, Zhengzheng S.; Amro Zayed; Ruiqiang Li; Robinson, Gene E.; Rodriguez-Zas, Sandra L.

    2016-01-01

    Among forager honey bees, scouts seek new resources and return to the colony, enlisting recruits to collect these resources. Differentially expressed genes between these behaviors and genetic variability in scouting phenotypes have been reported. Whole-genome sequencing of 44 Apis mellifera scouts and recruits was undertaken to detect variants and further understand the genetic architecture underlying the behavioral differences between scouts and recruits. The median coverage depth in recruit...

  1. CANNABINOID AND OPIOID MODULATION OF SOCIAL PLAY BEHAVIOR IN ADOLESCENT RATS: DIFFERENTIAL BEHAVIORAL MECHANISMS

    OpenAIRE

    Trezza, Viviana; Vanderschuren, Louk J. M. J.

    2008-01-01

    We have recently shown that the pharmacological mechanisms through which cannabinoid and opioid drugs influence social play behavior in adolescent rats can be partially dissociated. Here, we characterize the effects of the direct cannabinoid agonist WIN55,212-2, the indirect cannabinoid agonist URB597 and the opioid agonist morphine on social play at the behavioral level. By treating either one or both partners of the test dyad, we show that these drugs differentially affect play solicitation...

  2. Differential reinforcement of other behavior (DRO) to reduce aggressive behavior following traumatic brain injury.

    Science.gov (United States)

    Hegel, M T; Ferguson, R J

    2000-01-01

    Severe brain injury can result in significant neurobehavioral and social functioning impairment. In rehabilitation settings, behavioral problems of aggression and nonadherence to therapeutic activities can pose barriers to maximal recovery of function. Behavioral interventions seem to be effective in reducing problem behavior among individuals recovering from severe brain trauma, but well-controlled studies examining the efficacy of such interventions are sparse. This article presents a single-case, multiple-baseline study of a differential reinforcement of other behavior (DRO) procedure in a 28-year-old, brain-injured male with aggressive behavior problems. The procedure successfully reduced the frequency of problem behavior by up to 74%, maintained at 1-month follow-up. Implications of this intervention for individuals with brain injury are discussed, and testing of this procedure using a between-group design seems indicated.

  3. Microstructure and damping behavior of SiCp/Gr/2024Al metal matrix composites by squeeze casting technology

    Institute of Scientific and Technical Information of China (English)

    LENG Jin-feng; WU Gao-hui

    2006-01-01

    SiCp/Gr/2024Al metal matrix composites were processed by squeeze casting technology. The microstructure of composites was observed by SEM and TEM, and the effects of graphite particulates and SiC particulates on the damping behaviors of composites were also investigated. The results show that the microstructure of composites was dense and homogeneous, without any interfacial reactivity among reinforcement/matrix interfaces. Compared with the damping capacity of 2024Al, the damping capacity of composites was enhanced significantly by addition of SiC or graphite particulates. The main damping mechanisms of SiCp/Al composites were ascribed to the dislocation damping, and those of SiCp/Gr/2024Al were attributed to the intrinsic damping and interface damping.

  4. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    Science.gov (United States)

    Ge, Lin; Li, Jiang; Qu, Haiyun; Wang, Juntao; Liu, Jiao; Dai, Jiawei; Zhou, Zhiwei; Liu, Binglong; Kou, Huamin; Shi, Yun; Wang, Zheng; Pan, Yubai; Gao, Qingsong; Guo, Jingkun

    2016-10-01

    The sintering behavior and doping concentration profile of the planar waveguide YAG/Nd:YAG/YAG ceramics by the tape casting and solid-state reaction method were investigated on the basis of densification trajectory, microstructure evolution, and Nd3+ ions diffusion. The porosity of the green body by tape casting and cold isostatic pressing is about 38.6%. And the green bodies were consolidated from 1100 °C to 1800 °C for 0.5-20 h to study the densification and the doping diffusion behaviors. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. With the increase of temperature, two sintering stages occur, corresponding to remarkable densification and significant grain growth, respectively. The mechanism controlling densification at 1550 °C is grain boundary diffusion. The diffusion of Nd3+ ions is more sensitive to temperature than the sintering time, and the minimum temperature required for the obvious diffusion of Nd3+ ions is higher than 1700 °C. Finally, planar waveguide YAG/1.5 at.%Nd:YAG/YAG transparent ceramics with in-line transmittance of 84.8% at 1064 nm were obtained by vacuum-sintering at 1780 °C for 30 h. The fluorescence lifetime of 4F3/2 state of Nd3+ in the specimen is about 259 μs. The prepared ceramic waveguide was tested in a laser amplifier and the laser pulse was amplificated from 87 mJ to 238 mJ, with the pump energy of 680 mJ.

  5. Leaching Behavior and Potential Environmental Effects of Trace Elements in Coal Gangue of an Open-Cast Coal Mine Area, Inner Mongolia, China

    OpenAIRE

    Liu Yang; Jianfei Song; Xue Bai; Bo Song; Ruduo Wang; Tianhao Zhou; Jianli Jia; Haixia Pu

    2016-01-01

    In order to better understand the role of coal gangue in potential environmental and ecological risks, the leaching behavior of trace elements from coal gangue has been investigated in an open-cast coal mine, Inner Mongolia, China. Four comparative column leaching experiments were conducted to investigate the impacts of leaching time, pH values and sample amount on the leaching behavior of trace elements. Enrichment factors (EF), maximum leached amount (Lam), maximum leachability (Lrm), effec...

  6. Behavior learning in differential games and reorientation maneuvers

    Science.gov (United States)

    Satak, Neha

    method is the Direct Approximation of Value Function (DAVF) method. In this method, unlike the CSR method, the player formulates an objective function for the opponent but does not formulates a strategy directly; rather, indirectly the player assumes that the opponent is playing optimally. Thus, a value function satisfying the HJB equation corresponding to the opponent's cost function exists. The DAVF method finds an approximate solution for the value function based on previous observations of the opponent's control. The approximate solution to the value function is then used to predict the opponent's future behavior. Game examples in which only a single player is learning its opponent's behavior are simulated. Subsequently, examples in which both players in a two-player game are learning each other's behavior are simulated. In the second part of this research, a reorientation control maneuver for a spinning spacecraft will be developed. This will aid the application of behavior learning and differential games concepts to the specific scenario involving multiple spinning spacecraft. An impulsive reorientation maneuver with coasting will be analytically designed to reorient the spin axis of the spacecraft using a single body fixed thruster. Cooperative maneuvers of multiple spacecraft optimizing fuel and relative orientation will be designed. Pareto optimality concepts will be used to arrive at mutually agreeable reorientation maneuvers for the cooperating spinning spacecraft.

  7. The skin effect and the yielding behavior of cold chamber high pressure die cast Mg-Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yang, K. Vanna [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Caceres, C.H., E-mail: c.caceres@uq.edu.au [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Nagasekhar, A.V. [ARC Centre of Excellence for Design in Light Metals, Materials Engineering School of Engineering, University of Queensland, Brisbane, QLD, 4072 (Australia); Easton, M.A. [CAST Co-operative Research Centre, Department of Materials Engineering Monash University, Melbourne, VIC, 3800 (Australia)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The area fraction of elastic skin was calculated for a range of Mg-Al alloys. Black-Right-Pointing-Pointer The skin was defined using micro mechanistic concepts and tensile testing data. Black-Right-Pointing-Pointer The elastic constraint imposed by the skin on the core is discussed. Black-Right-Pointing-Pointer The skin covers {approx}30% of the cross section of the most concentrated alloy. - Abstract: The volume fraction of material that remained elastic as yielding developed in cast-to-shape tensile specimens of binary alloys with Al contents between 0.47 and 11.6 mass% was calculated using the Kocks-Mecking method of analysis. In the most dilute alloys the elastic fraction decreased rapidly to zero at a well-defined stress, suggesting that yielding was uniform across the specimen, whereas in the concentrated ones it decreased gradually over a wide range of stresses, suggesting that yielding developed first in the softer core of the casting while the harder outer layer, or skin, remained elastic. Comparison with specimens of the concentrated alloys which had a surface layer removed showed that the strain hardening behavior of the core resembled that of full specimens of the most dilute alloy. The maximum amount of elastic material in comparison with the most dilute alloy was used to define the area fraction covered by the skin, for each alloy. The skin covered between {approx}10% and {approx}30% of the cross section, the greater values for the concentrated alloys. The skin imposed an elastic constraint that delayed the development of full plasticity at the core.

  8. Comparative analysis of the behavior to corrosion of forged and cast austenitic stainless steel when used in a surgical prosthesis

    International Nuclear Information System (INIS)

    The selection of a material to be used in implants involves tests that cover aspects relative to its resistance to corrosion and its bio-compatibility. Testing the material implanted in the human body is a very difficult process or it is impossible via direct electrochemistry. Because of this laboratory tests have been developed that simulate the natural setting of the material in the organism using saline solutions that are kept at 37oC and pH 7.4. The material that is to be used should be resistant to corrosion in the body so that ions are not released into the organism and the device should maintain its integrity in service and not to suffer degradation. This work compares the behavior to corrosion of samples of a cast prosthesis (lower tibia, made of stainless steel ACI CF 3M) and a forged prosthesis (femorals, made of stainless steel ASTM F 621) with laminated bars of the same quality (stainless steel ASTM F 138). The samples were characterized with physical and electrochemical tests under three different thermal conditions: solubilized, annealed and forged or cast. The test pieces were submitted to electrochemical direct current tests during their immersion in a 0.9% deoxygenated NaCl solution and thermostatisized at 37oC. The Cr and Fe content in solution at the end of the electrochemical test was evaluated together with the micro hardness of the material and the characterization of the final stage of the material was carried out by optic microscopy and sweep electronics (CW)

  9. A Comparison of Response Cost and Differential Reinforcement of Other Behavior to Reduce Disruptive Behavior in a Preschool Classroom

    Science.gov (United States)

    Conyers, Carole; Miltenberger, Raymond; Maki, Amber; Barenz, Rebecca; Jurgens, Mandy; Sailer, Angela; Haugen, Meredith; Kopp, Brandon

    2004-01-01

    This study investigated the effectiveness of response cost and differential reinforcement of other behavior (DRO) in reducing the disruptive behaviors of 25 children in a preschool classroom. Using an alternating treatments design, disruptive behavior was reduced when the participants earned tokens for the absence of disruptive behavior (DRO) or…

  10. A comparison of response cost and differential reinforcement of other behavior to reduce disruptive behavior in a preschool classroom.

    Science.gov (United States)

    Conyers, Carole; Miltenberger, Raymond; Maki, Amber; Barenz, Rebecca; Jurgens, Mandy; Sailer, Angela; Haugen, Meredith; Kopp, Brandon

    2004-01-01

    This study investigated the effectiveness of response cost and differential reinforcement of other behavior (DRO) in reducing the disruptive behaviors of 25 children in a preschool classroom. Using an alternating treatments design, disruptive behavior was reduced when the participants earned tokens for the absence of disruptive behavior (DRO) or lost tokens for the occurrence of disruptive behavior (response cost). Initially, DRO was more successful in reducing the number of disruptive behaviors; however, over time, response cost proved to be more effective.

  11. Comprehensive behavioral analysis of cluster of differentiation 47 knockout mice.

    Directory of Open Access Journals (Sweden)

    Hisatsugu Koshimizu

    Full Text Available Cluster of differentiation 47 (CD47 is a member of the immunoglobulin superfamily which functions as a ligand for the extracellular region of signal regulatory protein α (SIRPα, a protein which is abundantly expressed in the brain. Previous studies, including ours, have demonstrated that both CD47 and SIRPα fulfill various functions in the central nervous system (CNS, such as the modulation of synaptic transmission and neuronal cell survival. We previously reported that CD47 is involved in the regulation of depression-like behavior of mice in the forced swim test through its modulation of tyrosine phosphorylation of SIRPα. However, other potential behavioral functions of CD47 remain largely unknown. In this study, in an effort to further investigate functional roles of CD47 in the CNS, CD47 knockout (KO mice and their wild-type littermates were subjected to a battery of behavioral tests. CD47 KO mice displayed decreased prepulse inhibition, while the startle response did not differ between genotypes. The mutants exhibited slightly but significantly decreased sociability and social novelty preference in Crawley's three-chamber social approach test, whereas in social interaction tests in which experimental and stimulus mice have direct contact with each other in a freely moving setting in a novel environment or home cage, there were no significant differences between the genotypes. While previous studies suggested that CD47 regulates fear memory in the inhibitory avoidance test in rodents, our CD47 KO mice exhibited normal fear and spatial memory in the fear conditioning and the Barnes maze tests, respectively. These findings suggest that CD47 is potentially involved in the regulation of sensorimotor gating and social behavior in mice.

  12. A Comparison of Function-Based Differential Reinforcement Interventions for Children Engaging in Disruptive Classroom Behavior

    Science.gov (United States)

    LeGray, Matthew W.; Dufrene, Brad A.; Sterling-Turner, Heather; Olmi, D. Joe; Bellone, Katherine

    2010-01-01

    This study provides a direct comparison of differential reinforcement of other behavior (DRO) and differential reinforcement of alternative behavior (DRA). Participants included three children in center-based classrooms referred for functional assessments due to disruptive classroom behavior. Functional assessments included interviews and brief…

  13. Monotonic and cyclic deformation behavior of MIG-CMT welded and heat-treated joints of aluminum cast and wrought alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kantehm, Matthias; Soeker, Marcus; Krupp, Ulrich; Michels, Wilhelm [Faculty of Engineering and Computer Science, Institute of Materials Design and Structural Integrity, University of Applied Sciences Osnabrueck, 49009 Osnabrueck (Germany)

    2012-10-15

    While the fatigue behavior of die cast aluminum as well as welded aluminum wrought alloys have been subject of several studies, no systematic work has been carried out on hybrid structures made as a combination of welded sand castings and wrought alloys. Aim of the present study is to correlate the monotonic and cyclic deformation behavior of thin sheet welded joints with the microstructure in the heat affected zone of the material combination sand cast EN AC-Al Si7Mg0.3 and wrought alloy EN AW-Al Si1MgMn (EN AW-6082). The metal sheets were welded using a metal inert gas cold metal transfer process under variation of the welding gap, the heat treatment parameters, as well as the surface finishes. It was demonstrated by Woehler diagrams based on bending fatigue tests that the fatigue life could be increased for the welded and heat treated specimens as compared to the as-received cast specimens. By means of optical microscopy this effect was attributed to microstructural changes due to the optimized welding and heat treatment process. A detailed analysis of the mechanical tests was possible by the application of an optical 3D strain analysis. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. OSCILLATION BEHAVIOR OF SOLUTIONS FOR EVEN ORDER NEUTRAL FUNCTIONAL DIFFERENTIAL EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    T.Candan

    2006-01-01

    Even order neutral functional differential equations are considered. Sufficient conditions for the oscillation behavior of solutions for this differential equation are presented. The new results are presented and some examples are also given.

  15. Behavior of surface residual stress in explosion hardened high manganese austenitic cast steel due to repeated impact loads

    International Nuclear Information System (INIS)

    Explosion hardened high manganese austenitic cast steel is being tried for rail crossing recently. From the previous studies, it became clear that high tensile residual stress was generated in the hardened surface layer by explosion and microcracks were observed. In this study, therefore, the behavior of surface residual stress in explosion hardened steel due to repeated impact loads was examined and compared with those of the original and shot peened steels. The results obtained are summarized as follows: (1) In the initial stage of the repetition of impact, high tensile surface residual stress in explosion hardened steel decreased rapidly with the repetition of impact, while those of the original and shot peened steels increased rapidly. This difference was attributed to the difference in depth of the work hardened layer in three testing materials. (2) Beyond 20 impacts the residual stress of three test specimens decreased gradually, and at more than 2000 impacts the compressive stress of about 500 MPa was produced regardless of the histories of working of testing materials. (3) The linear law in the second stage of residual stress fading was applicable to this case, and the range of the linear relationship was related to the depth of the work hardened layer of testing material. (4) From the changes in half-value breadth and peak intensity of diffraction X-ray, it was supposed that a peculiar microscopic strain exists in explosion hardened steel. (author)

  16. Thermomechanical behavior of dry contacts in disc brake rotor with a grey cast iron composition

    Directory of Open Access Journals (Sweden)

    Belhocine Ali

    2013-01-01

    Full Text Available The main purpose of this study is to analysis the thermomechanical behavior of the dry contact between the brake disc and pads during the braking phase. The simulation strategy is based on the calculation code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

  17. A comparison of response cost and differential reinforcement of other behavior to reduce disruptive behavior in a preschool classroom.

    OpenAIRE

    Conyers, Carole; Miltenberger, Raymond; Maki, Amber; Barenz, Rebecca; Jurgens, Mandy; Sailer, Angela; Haugen, Meredith; Kopp, Brandon

    2004-01-01

    This study investigated the effectiveness of response cost and differential reinforcement of other behavior (DRO) in reducing the disruptive behaviors of 25 children in a preschool classroom. Using an alternating treatments design, disruptive behavior was reduced when the participants earned tokens for the absence of disruptive behavior (DRO) or lost tokens for the occurrence of disruptive behavior (response cost). Initially, DRO was more successful in reducing the number of disruptive behavi...

  18. Differential Reinforcement of Alternative Behavior in Center-Based Classrooms: Evaluation of Pre-Teaching the Alternative Behavior

    Science.gov (United States)

    LeGray, Matthew W.; Dufrene, Brad A.; Mercer, Sterett; Olmi, D. Joe; Sterling, Heather

    2013-01-01

    This study investigated the effectiveness of a differential reinforcement of alternative behavior procedure in decreasing disruptive behavior while simultaneously increasing the appropriate behavior of four children of typical development between the ages of 4 and 6 in center-based classrooms. We began with brief functional analyses for each…

  19. Influence of heat treatment on the microstructure and wear behavior of end-chill cast Zn-27Al alloys with different copper content

    Science.gov (United States)

    Jeshvaghani, R. Arabi; Ghahvechian, H.; Pirnajmeddin, H.; Shahverdi, H. R.

    2016-04-01

    The aim of this paper was to study the effect of heat treatment on the microstructure and wear behavior of Zn-27Al alloys with different copper content. In order to study the relationship between microstructure features and wear behavior, the alloys prepared by an end-chill cast apparatus and then heat treated. Heat treatment procedure involved solutionizing at temperature of 350 °C for 72 h followed by cooling within the furnace to room temperature. Microstructural characteristics of as-cast and heat-treated alloys at different distances from the chill were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction. Wear tests were performed using a pin-on-disk test machine. To determine the wear mechanisms, the worn surfaces of the samples were also examined by SEM and EDS. Results showed that heat treatment led to the complete dissolution of as-cast dendritic microstructure and formation of a fine lamellar structure with well-distributed microconstituents. Moreover, addition of copper up to 1 wt% had no significant change in the microstructure, while addition of 2 and 4 wt% copper resulted in formation of ɛ (CuZn4) particle in the interdendritic regions. The influence of copper content on the wear behavior of the alloys was explained in terms of microstructural characteristics. Delamination was proposed as the dominant wear mechanism.

  20. Aging Behavior of Mg-Y-Zr and Mg-Nd-Zr Cast Alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Aging behavior of Mg-3.6Y-0.5Zr and Mg-2.7Nd-0.5Zr alloys was investigated by microhardness measurement and transmission electron microscopy. In the case of Mg-Y-Zr alloy, the presence of β″ phase, a major strengthener, having base centered orthorhombic structure with its lattice constants of aβ″=0.64 nm, bβ″=2.22 nm,and cβ″=0.52 nm was identified. In the case of Mg-Nd-Zr alloy aged at 250℃, the presence ofβ″ and β′phases was identified. The crystal structure ofβ″ phase was found to be DO19 and its orientation relationships with Mg matrix were [0001]β″//[0001]Mg and [01-10]β″//[0110]Mg. The β′ phase had face centered cubicstructure and its orientation relationships with Mg matrix were [011]β′//[0001]Mg and [-11-1]β′//[-2110]Mg.The Mg-2.7Nd-0.5Zr alloy showed higher hardness compared with Mg-3.6Y-0.5Zr alloy.

  1. Reduction of Multiple Aberrant Behaviors and Concurrent Development of Self-Care Skills with Differential Reinforcement.

    Science.gov (United States)

    Vollmer, Timothy R.; And Others

    1992-01-01

    A modified functional analysis was used to assess the behavioral function of a profoundly retarded man's self-injurious behavior (SIB). Differential reinforcement of alternative behavior effectively reduced SIB and related behavior problems, while compliance of a self-care acquisition task increased markedly. (Author/DB)

  2. Cast iron - a predictable material

    Directory of Open Access Journals (Sweden)

    Jorg C. Sturm

    2011-02-01

    Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven

  3. SPRAY CASTING

    OpenAIRE

    SALAMCI, Elmas

    2010-01-01

    ABSTRACT This paper is designed to provide a basic review of spray casting. A brief overview of the historical development of spray  casting and the description of plant and equipment have been given. Following metallurgical characteristics of spray formed alloys, process parameters and solidification mechanism of spray deposition have been discussed in detail. Finally, microstructure and mechanical properties of the selected spray cast Al-Zn-Mg-Cu alloys have been presented and compared...

  4. Differential effects of dietary oils on emotional and cognitive behaviors.

    Directory of Open Access Journals (Sweden)

    Keiko Kato

    Full Text Available Several dietary oils have been used preventatively and therapeutically in the setting of neurological disease. However, the mechanisms underlying their influence on brain function and metabolism remain unknown. It was investigated whether 3 types of dietary oils affected emotional behaviors in mice. Wild-type (WT mice and sialyltransferase ST3Gal IV-knockout (KO mice, which exhibit increased emotional and cognitive behaviors, were fed diets containing 20% dietary oils from post-weaning to adulthood. Mice were fed pellets made from control feed AIN93G powder containing 18% fish oil, soybean oil, or a mixture of 1-palmitoyl-2-oleoyl-3-palmitoyl glycerol (POP and 1-stearoyl-2-oleoyl-3-stearoyl glycerol (SOS, plus 2% soybean oil. Once mice reached adulthood, they were subjected to fear conditioning test to measure cognitive anxiety and forced swim test to measure depression. WT mice fed the POP-SOS diet showed a 0.6-fold decrease in percent freezing with contextual fear compared with WT mice fed the control diet. KO mice fed the fish oil diet showed a 1.4-fold increase in percent freezing with contextual fear compared with KO mice fed the control diet. These findings indicate that response to contextual fear was improved in WT mice that consumed POP-SOS but aggravated in KO mice that consumed fish oils. Furthermore, KO mice showed a 0.4-fold decrease in percent freezing in response to tone fear when they were fed POP-SOS diet compared to a control diet. Thus, POP-SOS diet reduced tone fear level of KO mice until the same level of WT mice. Finally, KO mice fed the soybean oil diet showed a 1.7-fold increase in immobility in the forced swim test compared to KO mice fed the control diet. Taken together, oil-rich diets differentially modulate anxiety and depression in normal and anxious mice. Oils rich in saturated fatty acids may alleviate anxiety more strongly than other oils.

  5. Creep Behavior at 1273 K (1000 °C) in Nb-Bearing Austenitic Heat-Resistant Cast Steels Developed for Exhaust Component Applications

    Science.gov (United States)

    Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

    2016-07-01

    A series of Nb-bearing austenitic heat-resistant cast steels with variations of N/C ratios were investigated, and the morphological change of Nb(C,N) from faceted blocks, mixed flake-blocks to "Chinese-script" was observed as N/C ratios decreased. The creep behavior of these alloys was studied at 1273 K (1000 °C), and the longest creep life and lowest creep rate occurred in model alloys with script Nb(C,N). Residual δ-ferrites and (Cr,Fe)23C6 were adverse to creep properties. This work indicates that the control of N/C ratio is required for the as-cast microstructural strengthening.

  6. Compressive behavior of NiAl/(Cr,Mo)Hf alloy prepared by high-pressure die casting and hot isostatic pressing

    Institute of Scientific and Technical Information of China (English)

    DU Xing-hao; GUO Jian-ting; WU Bao-lin

    2006-01-01

    The NiAl-28Cr-5.85Mo-0.15Hf alloy was prepared by high-pressure die casting (HPDC) and subsequent hot isostatic pressing(HIP), and tested for compressible strength and fracture behavior at 300-1 373 K. The results show that the elevated temperature 0.2% compressible yield strength as well as the room-temperature compressible fracture strain of as-HIP alloy are larger than those of the same alloy prepared by directional solidification (DS). It suggests that the fine structures with a homogeneous distribution of fine Cr(Mo)and Hf-rich phase created by high-pressure die casting lead to these improvements.

  7. Relationship between heat treatment, microstructure and creep rupture behavior of the nickel-base cast alloy IN 100

    International Nuclear Information System (INIS)

    The nickel-base cast alloy IN 100 is used for turbine blades for service in the temperature range above 800deg C. On account of the high proportion of the γ'-precipitation hardening phase of more than 50% IN 100 belongs the top group of high-temperature nickel-base superalloys. It is reported on investigations with IN 100 in order to better understand the casting-specific, large property variations and to define and to optimize the creep characteristics and the creep to rupture properties through variation of the γ'-precipitation hardening phase. It is explained how cast initial state, heat-treatment, microstructure, and the creep to rupture strength are linked with each other. (orig.)

  8. Differential Reinforcement to Reduce Disruptive Behaviors in a Blind Boy with a Learning Disability.

    Science.gov (United States)

    Heitzman, A. J.; Alimena, M. J.

    1991-01-01

    Differential reinforcement of low rates of responding was used to reduce the disruptive behaviors of a blind 12-year-old boy with a learning disability. The subject earned reinforcers by not exceeding the established criterion of disruptive behaviors. An overall 88 percent reduction in target behaviors was observed across a 26-day period.…

  9. Combining Noncontingent Reinforcement and Differential Reinforcement Schedules as Treatment for Aberrant Behavior.

    Science.gov (United States)

    Marcus, Bethany A.; Vollmer, Timothy R.

    1996-01-01

    In this study with three children (ages four and five) with severe developmental disabilities and aberrant behavior maintained by tangible positive reinforcement, noncontingent reinforcement, and differential reinforcement of alternative behavior were found to decrease the frequency of aberrant behavior while strengthening mands. (Author/DB)

  10. The effects of differential negative reinforcement of other behavior and noncontingent escape on compliance.

    OpenAIRE

    Kodak, Tiffany; Miltenberger, Raymond G.; Romaniuk, Cathryn

    2003-01-01

    The present study evaluated the effects of noncontingent escape and differential negative reinforcement of other behavior in reducing problem behaviors and increasing compliance in 2 children with disabilities. Results showed that both methods reduced problem behavior and increased compliance for both children.

  11. Differential reinforcement of alternative behavior and demand fading in the treatment of escape-maintained destructive behavior.

    OpenAIRE

    Piazza, C C; Moes, D R; Fisher, W W

    1996-01-01

    The escape-maintained destructive behavior of a boy with autism was reduced during instructional sequences with differential reinforcement of compliance (DRA), escape extinction without physical guidance, and demand fading. The procedure decreased destructive behaviors to near-zero levels and greatly increased compliance.

  12. Differential Reinforcement of Alternative Behavior and Demand Fading in the Treatment of Escape-Maintained Destructive Behavior.

    Science.gov (United States)

    Piazza, Cathleen C.; And Others

    1996-01-01

    A study of an 11-year-old boy with autism and mild mental retardation found that his escape-maintained destructive behavior was reduced during instructional sequences with differential reinforcement of compliance, escape extinction without physical guidance, and demand fading. The procedure decreased destructive behaviors to near-zero levels and…

  13. Teacher Implementation of Trial-Based Functional Analysis and Differential Reinforcement of Alternative Behavior for Students with Challenging Behavior

    Science.gov (United States)

    Flynn, Susan D.; Lo, Ya-yu

    2016-01-01

    The purpose of this study was to examine the effects of a training package on three middle school special education teachers' accurate implementation of trial-based functional analysis (TBFA) and differential reinforcement of alternative behavior (DRA) with their students with autism spectrum disorders or emotional and behavioral disorders in the…

  14. Effects of boron on the fracture behavior and ductility of cast Ti–6Al–4V alloys

    International Nuclear Information System (INIS)

    Minor amounts of boron additions have been found to greatly enhance the ductility of cast Ti–6Al–4V alloys, which was considered to be due to the grain-size refinement. In this paper, we report our interesting finding that the beneficial effect of boron on the ductility of the cast titanium alloys is due not only to the grain-size refinement but the enhancement of the prior-β grain-boundary cohesion by boron segregation at the grain boundaries, as evidenced by Auger electron microscopy

  15. Corrosion behavior of as-cast Mg-8Li-3Al+ xCe alloy in 3.5wt% NaCl solution

    Science.gov (United States)

    Manivannan, S.; Dinesh, P.; Mahemaa, R.; MariyaPillai, Nandhakumaran; Kumaresh Babu, S. P.; Sundarrajan, Srinivasan

    2016-10-01

    Mg-8Li-3Al+ xCe alloys ( x = 0.5wt%, 1.0wt%, and 1.5wt%) were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion behavior of the as-cast Mg-8Li-3Al+ xCe alloys were studied under salt spray tests in 3.5wt% NaCl solution at 35°C, in accordance with standard ASTM B-117, in conjunction with potentiodynamic polarization (PDP) tests. The results show that the addition of Ce to Mg-8Li-3Al (LA83) alloy results in the formation of Al2Ce intermetallic phase, refines both the α-Mg phase and the Mg17Al12 intermetallic phase, and then increases the microhardness of the alloys. The results of PDP and salt spray tests reveal that an increase in Ce content to 1.5wt% decreases the corrosion rate. The best corrosion resistance is observed for the LA83 alloy sample with 1.0wt% Ce.

  16. Effects of the Exposure to Corrosive Salts on the Frictional Behavior of Gray Cast Iron and a Titanium-Based Metal Matrix Composite

    Energy Technology Data Exchange (ETDEWEB)

    Blau, Peter Julian [ORNL; Truhan, Jr., John J [ORNL; Kenik, Edward A [ORNL

    2007-01-01

    The introduction of increasingly aggressive road-deicing chemicals has created significant and costly corrosion problems for the trucking industry. From a tribological perspective, corrosion of the sliding surfaces of brakes after exposure to road salts can create oxide scales on the surfaces that affect friction. This paper describes experiments on the effects of exposure to sodium chloride and magnesium chloride sprays on the transient frictional behavior of cast iron and a titanium-based composite sliding against a commercial brake lining material. Corrosion scales on cast iron initially act as abrasive third-bodies, then they become crushed, spread out, and behave as a solid lubricant. The composition and subsurface microstructures of the corrosion products on the cast iron were analyzed. Owing to its greater corrosion resistance, the titanium composite remained scale-free and its frictional response was markedly different. No corrosion scales were formed on the titanium composite after aggressive exposure to salts; however, a reduction in friction was still observed. Unlike the crystalline sodium chloride deposits that tended to remain dry, hygroscopic magnesium chloride deposits absorbed ambient moisture from the air, liquefied, and retained a persistent lubricating effect on the titanium surfaces.

  17. Rotary bending fatigue behavior of A356 –T6 aluminum alloys by vacuum pressurizing casting

    Directory of Open Access Journals (Sweden)

    Yong-qin Liu

    2015-09-01

    Full Text Available Vacuum pressurizing casting technique, providing better mould filling and inter-dendritic feeding, can reduce the porosity greatly in cast aluminum alloys, and improve the fatigue properties. The rotary bending fatigue properties of A356-T6 alloys prepared by vacuum pressurizing casting were investigated. The S-N curve and limit strength 90 MPa under fatigue life of 107 cycles were obtained. The analyses on the fatigue fractography and microstructure of specimens showed that the fatigue fracture mainly occurs at the positions with casting defects in the subsurface, especially at porosities regions, which attributed to the crack propagation during the fatigue fracture process. Using the empirical crack propagation law of Pairs-Erdogon, the quantitative relationship among the initial crack size, fatigue life and applied stress was established. The fatigue life decreases with an increase in initial crack size. Two constants in the Pairs-Erdogon equation of aluminum alloy A356-T6 were calculated using the experimental data.

  18. Local behavior of autonomous neutral functional differential equations.

    Science.gov (United States)

    Hale, J. K.

    1972-01-01

    Basic problems for a special class of neutral functional differential equations (NFDE) are formulated, and some contributions to a general qualitative theory in the neighborhood of an equilibrium point are indicated. The properties of a NFDE (G,f) are examined to determine in what sense these properties are insensitive to small changes in (G,f) in the topology G x F. The special class of equations that is introduced includes retarded functional differential equations and difference equations.

  19. 水平连铸灰铁HT250型材的阻尼行为%Damping Behavior of Grey Cast Iron HT250 Dense Bar Fabricated by Horizontal Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    张忠明; 王锦程; 马莹; 李伟明; 徐春杰; 王刚

    2012-01-01

    选用直径为55 mm的水平连铸灰铁HT250棒材,利用动态热机械分析仪测试型材的阻尼性能随振幅、频率和温度的变化关系,探讨灰铸铁型材的阻尼机制.研究表明,灰铸铁型材的阻尼性能随振幅和频率的提高而增加.在40℃附近出现斯诺克温度内耗峰.斯诺克峰的出现,使型材的阻尼性能随温度的变化在高低温时表现出完全不同的趋势.存在一临界应变振幅范围,大应变振幅下的阻尼性能远高于小应变振幅下的阻尼性能.灰铸铁型材的阻尼温度效应主要来源于点缺陷阻尼.位错阻尼在阻尼频率效应和阻尼振幅效应中起了主导作用,决定了型材的阻尼-频率行为和阻尼振幅行为.%The variation of damping behavior with vibration amplitude, frequency and temperature in grey cast iron HT250 dense bar produced by horizontal continuous casting was measured by dynamic mechanical analyzer to understand the damping mechanism of the alloy. The results show that the damping behavior is increased with increasing in amplitude and frequency. An internal friction peak occurs at about 40 "C and is extrapolated by Snoek relaxation. The damping temperature curve shows inverse tendencies at higher temperature range and lower temperature range as a result of the occurrence of Snoek peak. There exists a critical amplitude range, and the damping behavior at higher amplitude is much higher than that at lower amplitude. The temperature-dependent damping capacity mainly is resulted from point-defect damping, while dislocation damping is predominant in the frequency-dependent damping and amplitude-dependent damping, which controls the damping behavior of the alloy.

  20. Asymptotic behavior of solutions to a class of linear non-autonomous neutral delay differential equations

    OpenAIRE

    Guiling Chen

    2011-01-01

    We study a class of linear non-autonomous neutral delay differential equations, and establish a criterion for the asymptotic behavior of their solutions, by using the corresponding characteristic equation.

  1. Fillability of Thin-Wall Steel Castings

    Energy Technology Data Exchange (ETDEWEB)

    Robert C. Voigt; Joseph Bertoletti; Andrew Kaley; Sandi Ricotta; Travis Sunday

    2002-07-30

    The use of steel components is being challenged by lighter nonferrous or cast iron components. The development of techniques for enhancing and ensuring the filability of thin-wall mold cavities is most critical for thinner wall cast steel production. The purpose of this research was to develop thin-wall casting techniques that can be used to reliably produce thin-wall castings from traditional gravity poured sand casting processes. The focus of the research was to enhance the filling behavior to prevent misrunds. Experiments were conducted to investigate the influence of various foundry variables on the filling of thin section steel castings. These variables include casting design, heat transfer, gating design, and metal fluidity. Wall thickness and pouring temperature have the greatest effect on casting fill. As wall thickness increases the volume to surface area of the casting increases, which increases the solidification time, allowing the metal to flow further in thicker sect ions. Pouring time is another significant variable affecting casting fill. Increases or decreases of 20% in the pouring time were found to have a significant effect on the filling of thin-wall production castings. Gating variables, including venting, pouring head height, and mold tilting also significantly affected thin-wall casting fill. Filters offer less turbulent, steadier flow, which is appropriate for thicker castings, but they do not enhance thin-wall casting fill.

  2. CYCLIC PLASTIC BEHAVIOR AND FATGIUE LIFE OF AZ91 ALLOY IN AS-CAST AND ULTRAFINE-GRAINED STATE

    OpenAIRE

    Stanislava Fintová; Ludvík Kunz

    2014-01-01

    Fatigue properties of magnesium alloy AZ91 in as-cast and in ultrafine-grained state prepared by equal channel angular pressing were investigated. The fatigue strength in the low-cycle fatigue region was found to be substantially improved by the severe plastic deformation, whereas the improvement in the high-cycle fatigue region is negligible. The cyclic plastic response in both states is qualitatively similar; short initial softening is followed by a long cyclic hardening. The observed fatig...

  3. Predicting Stress vs. Strain Behaviors of Thin-Walled High Pressure Die Cast Magnesium Alloy with Actual Pore Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoo Sil; Barker, Erin I.; Cheng, Guang; Sun, Xin; Forsmark, Joy; Li, Mei

    2016-05-01

    In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to the experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results. This indicates that the developed 3D extrinsic modeling method may be used to examine the influence of various aspects of pore sizes/distributions as well as intrinsic properties (i.e., matrix properties) on the ductility/fracture of Mg castings.

  4. Solidification and casting

    CERN Document Server

    Cantor, Brian

    2002-01-01

    INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo

  5. Comparing Main and Collateral Effects of Extinction and Differential Reinforcement of Alternative Behavior

    Science.gov (United States)

    Petscher, Erin Seligson; Bailey, Jon S.

    2008-01-01

    This study evaluated the effects and collateral effects of extinction (EXT) and differential reinforcement of alternative behavior (DRA) interventions with inappropriate vocalizations and work refusal. Both interventions have been used frequently to reduce problem behaviors. The benefits of these interventions have been established yet may be…

  6. Oscillatory and Asymptotic Behavior of a Second-Order Nonlinear Functional Differential Equations

    Institute of Scientific and Technical Information of China (English)

    张全信; 高丽; 王少英

    2012-01-01

    This paper is concerned with oscillatory and asymptotic behavior of solutions of a class of second order nonlinear functional differential equations. By using the generalized Riccati transformation and the integral averaging technique, new oscillation criteria and asymptotic behavior are obtained for all solutions of the equation. Our results generalize and improve some known theorems.

  7. Differential Reinforcement of Other Behavior Applied Classwide in a Child Care Setting

    Science.gov (United States)

    Daddario, Rosemarie; Anhalt, Karla; Barton, Lyle E.

    2007-01-01

    This study investigated the effectiveness of implementing Differential Reinforcement of Other behavior (DRO) at the classwide level to decrease the disruptive behavior of seven typically developing preschool-aged children in a child care setting. After baseline data were collected, a whole interval DRO reinforcement schedule using edible rewards…

  8. Differentiating Bulimic-Anorexic from Normal Families Using Interpersonal and Behavioral Observational Systems.

    Science.gov (United States)

    Humphrey, Laura Lynn; And Others

    1986-01-01

    Compared interpersonal and behavioral observational systems in their ability to differentiate families with a bulimic-anorexic daughter using the modified Marital Interaction Coding System (MICS) and the Structural Analysis of Social Behavior (SASB). Results showed both measures successfully discriminated between groups, accounting for…

  9. Differential self-assembly behaviors of cyclic and linear peptides.

    Science.gov (United States)

    Choi, Sung-ju; Jeong, Woo-jin; Kang, Seong-Kyun; Lee, Myongsoo; Kim, Eunhye; Ryu, Du Yeol; Lim, Yong-beom

    2012-07-01

    Here we ask the fundamental questions about the effect of peptide topology on self-assembly. The study revealed that the self-assembling behaviors of cyclic and linear peptides are significantly different in several respects, in addition to sharing several similarities. Their clear differences included the morphological dissimilarities of the self-assembled nanostructures and their thermal stability. The similarities include their analogous critical aggregation concentration values and cytotoxicity profiles, which are in fact closely related. We believe that understanding topology-dependent self-assembly behavior of peptides is important for developing tailor-made self-assembled peptide nanostructures.

  10. A chromatin link to caste identity in the carpenter ant Camponotus floridanus.

    Science.gov (United States)

    Simola, Daniel F; Ye, Chaoyang; Mutti, Navdeep S; Dolezal, Kelly; Bonasio, Roberto; Liebig, Jürgen; Reinberg, Danny; Berger, Shelley L

    2013-03-01

    In many ant species, sibling larvae follow alternative ontogenetic trajectories that generate striking variation in morphology and behavior among adults. These organism-level outcomes are often determined by environmental rather than genetic factors. Therefore, epigenetic mechanisms may mediate the expression of adult polyphenisms. We produced the first genome-wide maps of chromatin structure in a eusocial insect and found that gene-proximal changes in histone modifications, notably H3K27 acetylation, discriminate two female worker and male castes in Camponotus floridanus ants and partially explain differential gene expression between castes. Genes showing coordinated changes in H3K27ac and RNA implicate muscle development, neuronal regulation, and sensory responses in modulating caste identity. Binding sites of the acetyltransferase CBP harbor the greatest caste variation in H3K27ac, are enriched with motifs for conserved transcription factors, and show evolutionary expansion near developmental and neuronal genes. These results suggest that environmental effects on caste identity may be mediated by differential recruitment of CBP to chromatin. We propose that epigenetic mechanisms that modify chromatin structure may help orchestrate the generation and maintenance of polyphenic caste morphology and social behavior in ants. PMID:23212948

  11. A chromatin link to caste identity in the carpenter ant Camponotus floridanus.

    Science.gov (United States)

    Simola, Daniel F; Ye, Chaoyang; Mutti, Navdeep S; Dolezal, Kelly; Bonasio, Roberto; Liebig, Jürgen; Reinberg, Danny; Berger, Shelley L

    2013-03-01

    In many ant species, sibling larvae follow alternative ontogenetic trajectories that generate striking variation in morphology and behavior among adults. These organism-level outcomes are often determined by environmental rather than genetic factors. Therefore, epigenetic mechanisms may mediate the expression of adult polyphenisms. We produced the first genome-wide maps of chromatin structure in a eusocial insect and found that gene-proximal changes in histone modifications, notably H3K27 acetylation, discriminate two female worker and male castes in Camponotus floridanus ants and partially explain differential gene expression between castes. Genes showing coordinated changes in H3K27ac and RNA implicate muscle development, neuronal regulation, and sensory responses in modulating caste identity. Binding sites of the acetyltransferase CBP harbor the greatest caste variation in H3K27ac, are enriched with motifs for conserved transcription factors, and show evolutionary expansion near developmental and neuronal genes. These results suggest that environmental effects on caste identity may be mediated by differential recruitment of CBP to chromatin. We propose that epigenetic mechanisms that modify chromatin structure may help orchestrate the generation and maintenance of polyphenic caste morphology and social behavior in ants.

  12. Effect of Cu, Zn, and Mg Concentration on Heat Treating Behavior of Squeeze Cast Al-(10 to 12)Zn-(3.0 to 3.4)Mg-(0.8 to 1)Cu

    OpenAIRE

    Ferguson, J B; Benjamin F. Schultz; John C. Mantas; Hassan Shokouhi; Pradeep K. Rohatgi

    2014-01-01

    Aluminum Alloy AA-7034 is a high strength wrought alloy with reasonable ductility containing 10–12 wt% Zn, 2–3 wt% Mg, and 0.8–1.2 wt% Cu. This work investigates the effect of varying the concentration of Zn (10–12 wt%) and Cu (0.8–1 wt%) on the solutionizing and aging behavior of squeeze cast AA-7034 samples. The same behaviors were investigated when Mg content was increased beyond 3 wt%. The solutionizing heat treatment dissolved much of the macroscopic second phases present in the as-cast ...

  13. Hot ductility and deformation behavior of C-Mn/Nb-microalloyed steel related to cracking during continuous casting

    OpenAIRE

    Lanjewar, Harishchandra; Tripathi, Pranavkumar; M Singhai; Patra, PK

    2014-01-01

    Hot ductility studies have been performed on C-Mn and C-Mn-Nb steels with an approach to simulate the effect of cooling conditions experienced by steel in secondary cooling zone during continuous casting. Thermal oscillations prior to tensile straining deteriorate hot ductility of steel by deepening and widening the hot ductility trough. C-Mn steels are found to exhibit ductility troughs in three distinct zones whereas C-Mn-Nb steel shows drop in ductility only at low temperature in the vicin...

  14. Microstructure and Wear Behavior of TiC Coating Deposited on Spheroidized Graphite Cast Iron Using Laser Surfacing

    OpenAIRE

    E. R. I. Mahmoud; H. F. El-Labban

    2014-01-01

    Spheroidal graphite cast iron was laser cladded with TiC powder using a YAG fiber laser at powers of 700, 1000, 1500 and 2000 W. The powder was preplaced on the surface of the specimens with 0.5 mm thickness. Sound cladding and fusion zones were observed at 700, 1000 and 1500 W powers. However, at 2000 W, cracking was observed in the fusion zone.  At 700 W, a build-up zone consisted of fine TiC dendrites inside a matrix composed of martensite, cementite (Fe3C), and some blocks of retaine...

  15. Electrochemical and Mechanical Behavior of Lead-Silver and Lead-Bismuth Casting Alloys for Lead-Acid Battery Components

    Science.gov (United States)

    Osório, Wislei R.; Peixoto, Leandro C.; Garcia, Amauri

    2015-09-01

    The present study focuses on the interrelation of microstructure, mechanical properties, and corrosion resistance of Pb-Ag and Pb-Bi casting alloys, which can be used in the manufacture of lead-acid battery components, as potential alternatives to alloys currently used. A water-cooled solidification system is used, in which vertical upward directional solidification is promoted permitting a wide range of microstructures to be investigated. Correlations between microstructural arrays, tensile strengths, and corrosion resistances of Pb-1 wt pct Ag, Pb-2.5 wt pct Ag, Pb-1 wt pct Bi, and Pb-2.5 wt pct Bi alloys are envisaged. It is shown that a compromise between corrosion resistance (represented by the corrosion current density) and mechanical properties (represented by the ultimate tensile strength) can be obtained. Comparisons between specific strengths and mechanical/corrosion ratios are also made. It is also shown that, for microstructures solidified under cooling rates higher than 10 K/s, the Pb-Ag alloys exhibit higher specific strength and mechanical/corrosion ratio. In contrast, for casting processes in which the cooling rates are lower than 5 K/s, the dilute Pb-Bi alloy ( i.e., 1 wt pct Bi) is shown to have more appropriate requirements for lead-acid battery components. Comparisons between specific strengths, mechanical/corrosion ratio, and relative weight and cost with Pb-Sn and Pb-Sb alloys are also made.

  16. Corrosion behavior of as-cast Mg_(68)Zn_(28)Y_4 alloy with I-phase

    Institute of Scientific and Technical Information of China (English)

    SHI Fei; YU Yuan-chun; GUO Xue-feng; ZHANG Zhong-ming; LI Ying-ying

    2009-01-01

    Mg_(68)Zn_(28)Y_4 alloys with stable icosahedral quasicrystals (Zn_(60)Mg_(30)Y_(10)) were prepared by cast method. By simulating the environment of ocean, the alloy was eroded in 3.5% (mass fraction) NaCl for 2, 4 and 30 h. The microstructures of the samples and eroded alloys were analyzed by OM and SEM. The compositions and the quasiperiodic structures were identified respectively by EDS and TEM. And the corrosion potential and corrosion current density before and after immersion were measured by potentiodynamic polarization measurements in 3.5% NaCl. The results show that I-phases grow in the mode of conglomeration, piling and transfixion. The Mg_7Zn_3 matrix and ((Mg) solid solution are eroded badly, while W-phase is eroded partially. At the same time, the I-phases exhibit excellent corrosion resistance property. The resistance to corrosion of Mg_(68)Zn_(28)Y_4 alloy is improved by increasing exposed I-phases. With adding element Y to Mg68Zn32 alloy, the corrosion current is decreased by one order of magnitude. And after the immersion of as-cast Mg_(68)Zn_(28)Y_4 alloy for 30 h, the corrosion current density is reduced by two orders of magnitude compared with that of uneroded Mg_(68)Zn_(32) alloy.

  17. Part I: In-situ fluorometric quantification of microalgal neutral lipids. Part II: Thermal degradation behavior of investment casting polymer patterns

    Science.gov (United States)

    Zhao, Hongfang

    Research described in this dissertation covers two topics. Part-I is focused on in-situ determination of neutral lipid content of microalgae using a lipophilic fluorescent dye. The traditional Nile red stain-based method for detecting microalgal intracellular lipids is limited due to varying composition and thickness of rigid cell walls. In this study, the addition of dilute acid and heating of solution, were found to greatly enhance staining efficiency of Nile red for microalgal species evaluated. Oil-in-water (O/W) microemulsion stabilized by a non-ionic surfactant was employed as a pseudo-standard that mimics lipid-bearing microalgal cells suspended in water. The average neutral lipid contents determined were very close to the results obtained by traditional gravimetric method and solid phase extraction. Part II of the dissertation explores thermo-physico-chemical properties of polymeric pattern materials, including expanded polystyrene (EPS) foam, polyurethane foam, and epoxy stereolithography (SLA) patterns, that are used in investment casting. Density, elastic modulus, expansion coefficient, thermal degradation behavior, etc. were experimentally investigated for their effects on metal casting quality. The reduction in toxic hydrogen cyanide (HCN) generated during thermal decomposition of polyurethane pattern was achieved by increasing either oxidant level or residence time in heated zone. Thermal degradation kinetics of the pattern materials were examined with a thermogravimetric analysis and activation energies were determined by Kissinger and Flynn-Wall-Ozawa methods.

  18. Microstructural effects on the wear behavior of a biomedical as-cast Co-27Cr-5Mo-0.25C alloy exposed to pulsed laser melting.

    Science.gov (United States)

    Acevedo-Dávila, J L; López, H F; Cepeda-Rodríguez, F; Rodriguez-Reyes, M; García-Vazquez, F; Hernández-Garcia, H M

    2014-06-01

    In this work, the effect of pulsed laser melting on the exhibited microstructure and properties of a cast Co-27Cr-5Mo-0.25C alloy was investigated. In particular, properties such as surface hardness and wear behavior of the laser modified microstructure were determined as a function of the implemented laser melting parameters. It was found that laser melting promotes significant grain refinement while preventing the precipitation of coarse carbide phases. Apparently, a refined dendritic grain structure develops which is surrounded by a fine carbide distribution in the interdendritic regions. Moreover, the high-temperature face centered cubic (FCC) phase remains untransformed at room temperature. Hardness measurements and wear testing using a Pin-On-Disk tribological machine indicate that the modified laser surfaces exhibit both, high wear resistance and high microhardness when compared with the untreated as-cast Co-27Cr-5Mo-0.25C alloy. In particular, it was found that the laser modified surfaces exhibit improved wear and friction properties comparable to the ones found in Co-Cr-Mo alloys with a predominantly hexagonal closest packed (HCP) matrix. However, surface defects associated with the laser process can be detrimental for the improved wear performance and they should be considered in identifying the proper laser parameters in alloy melting.

  19. Leaching Behavior and Potential Environmental Effects of Trace Elements in Coal Gangue of an Open-Cast Coal Mine Area, Inner Mongolia, China

    Directory of Open Access Journals (Sweden)

    Liu Yang

    2016-05-01

    Full Text Available In order to better understand the role of coal gangue in potential environmental and ecological risks, the leaching behavior of trace elements from coal gangue has been investigated in an open-cast coal mine, Inner Mongolia, China. Four comparative column leaching experiments were conducted to investigate the impacts of leaching time, pH values and sample amount on the leaching behavior of trace elements. Enrichment factors (EF, maximum leached amount (Lam, maximum leachability (Lrm, effects range low (ERL and effects range median (ERM were employed to evaluate potential environmental and ecological hazards resulting from the leaching behavior of environment-sensitive trace elements from coal gangue. Leaching time and sample amount display important effects on trace element concentrations, leached amounts and leachability. The pH values exhibit a weak influence on the leaching behavior of the selected trace elements (e.g., As, V, Cr, Co, Ni, Cu, Zn, Se, Cd, Sn, Pb and Hg. The coal gangue are enriched in As, Co, Se and Pb and, in particular, show higher environmental pollution levels of As and Se (EF > 2. Lam values suggest that all of the elements investigated do not show potential risk to soils and vegetation, but have a high hazard risk for ground water. Elements including Ni, As, Cr and Zn are inclined to show high or moderate biological toxicity.

  20. Effect of Ablation Casting on Microstructure and Casting Properties of A356 Aluminium Casting Alloy

    Institute of Scientific and Technical Information of China (English)

    V.Bohlooli; M.Shabani Mahalli; S.M.A.Boutorabi

    2013-01-01

    Recently the Ablation Casting Technology was invented as a new casting process to improve foundry products quality.In this study,the effects of processing variables on the porosity content,microstructure and feedability of A356 casting alloy were investigated.Secondary dendrite arm spacing (SDAS) and eutectic silicon morphologies were studied to evaluate the influence of Ablation Casting on the microstructure.Casting density was measured in order to identify porosity content and feedability of ablated and non-ablated specimens.In addition,solidification behavior of the samples was investigated by using thermal analysis technique.The cooling curves and the first derivative curves were plotted and compared with each other.Results showed the ablation process could increase solidification rate significantly.In addition,the microstructural evidences revealed that Ablation Casting process results in more fine and homogeneous structure compared to the nonablated casting.The feedability improved,SDAS reduced to 35% and porosity content decreased to 3.84 vol.% by implementing this process.It concluded the Ablation Casting is an effective process to gain higher quality in aluminum foundry.

  1. Wear Behavior of Al-Mg2Si Cast In-situ Composite: Effect of Mg2Si Different Volume Fractions

    Science.gov (United States)

    Ghiasinejad, J.; Emamy, M.; Ghorbani, M. R.; Malekan, A.

    2010-06-01

    Al-Mg2Si in situ composites are great candidates for automobile brake discs due to their low density, reasonably high young's modulus and low thermal expansion coefficient. Thus, understanding wear properties of this composite is of a great importance. In this study wear behavior of an in-situ Al-Mg2Si composite, prepared from a simple casting route, has been investigated using a pin-on-disc configuration concerning the effect of Mg2Si volume fractions, 15, 20 and 25% respectively. It was found that the weight loss increases with increase in reinforce volume fraction which can be due to a coarse morphology of primary Mg2Si particles. It was found that the variations of weight loss with sliding distance comprise different regimes of which the mechanisms are discussed.

  2. Microstructure and Wear Behavior Of as Cast Al-25mg2si-2cu-2ni Alloy

    Directory of Open Access Journals (Sweden)

    1Geetanjali.S.Guggari ,

    2015-09-01

    Full Text Available The remarkable feature of the Aluminium is its low density and ability to withstand corrosion effect due to phenomenon of passivation. Structural components made from Aluminium and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The oxides and sulphate are useful compounds of Aluminium based on its weight. In this work, an attempt has been made to utilize the combined effect of high cooling rate solidification, unique micro structural evolution mechanism of T6 heat treatment the advantages of hypereutectic Al-Si system alloyed with other elements such as Cu, Fe and Mg. In the present investigation, the binary alloys in the hypereutectic range viz. Al25Mg2Si has been selected as heat resistant Al-Si alloys. A systematic approach has been carried out to explore the micro structural features, mechanical and wear properties of as cast alloys.

  3. Area Method Analysis and Thermodynamic Behavior of Nonmetallic Micro-Inclusions in Casting Slab of GCr15 Bearing Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Hongli; MA Yitai; WANG Shuoming

    2009-01-01

    The distribution and characteristics of nonmetallic micro-inclusions of GCrI5 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.

  4. Grain refinement and macrosegregation behavior of direct chill cast Al-Zn-Mg-Cu alloy under combined electromagnetic fields

    Directory of Open Access Journals (Sweden)

    Yu-bo Zuo

    2015-09-01

    Full Text Available The combined electromagnetic fields were achieved by the application of an alternating magnetic field and a stationary magnetic field and were used during direct chill (DC casting process to control the microstructure and macrosegregation of an Al-Zn-Mg-Cu alloy. Ingot microstructures were analyzed under an optical microscope (Leica DMR. The composition at different locations in the ingots was measured with inductively coupled plasma mass spectrometry (ICP method. The results showed that the grain structure is transformed from dendrite to equiaxed structure and significantly refined with the application of combined electromagnetic fields. The uniformity of microstructure is also greatly improved. The combined electromagnetic fields show a significant effect on the distribution of elements. The negative macrosegregation in the centre area of the ingot is obviously reduced.

  5. Differential strain vulnerability to binge eating behaviors in rats.

    Science.gov (United States)

    Hildebrandt, Britny A; Klump, Kelly L; Racine, Sarah E; Sisk, Cheryl L

    2014-03-29

    Binge eating is a significantly heritable phenotype, but efforts to detect specific risk genes have fallen short. Identification of animal strain differences in risk for binge eating could highlight genetic differences across individuals of the same species that can be exploited in future animal and molecular genetic research. The current study aimed to explore strain differences in risk for binge eating in Sprague-Dawley versus Wistar female rats using the Binge Eating Resistant/Binge Eating Prone model. A sample of male Sprague-Dawley rats, a known low-risk group for binge eating, was included as a comparison group. A total of 83 rats (23 Wistar females, 30 Sprague-Dawley females, 30 Sprague-Dawley males) completed a protocol of intermittently administered, palatable food. Binge eating prone (BEP) and binge eating resistant (BER) rats were identified using a tertile approach. Sprague-Dawley female rats consumed the highest amount of palatable food and were more likely to be classified as BEP compared to Wistar female and Sprague-Dawley male rats. Wistar female rats were not significantly different from Sprague-Dawley male rats in their palatable food intake and tendency to be classified as BER rather than BEP. Sprague-Dawley female rats appear to be a particularly vulnerable genotype for binge eating. Comparisons between this group and others could help identify specific genetic/biological factors that differentiate it from lower risk groups. The reward system, linked to binge eating in humans, is a possible candidate to explore. Strain differences in the reward system could help increase understanding of individual differences in risk for binge eating in humans. PMID:24480076

  6. Gene expression changes in the tyrosine metabolic pathway regulate caste-specific cuticular pigmentation of termites.

    Science.gov (United States)

    Masuoka, Yudai; Maekawa, Kiyoto

    2016-07-01

    In social insects, all castes have characteristic phenotypes suitable for their own tasks and to engage in social behavior. The acquisition of caste-specific phenotypes was a key event in the course of social insect evolution. However, understanding of the genetic basis and the developmental mechanisms that produce these phenotypes is still very limited. In particular, termites normally possess more than two castes with specific phenotypes (i.e. workers, soldiers, and reproductives), but proximate developmental mechanisms are far from being fully understood. In this study, we focused on the pigmentation of the cuticle as a model trait for caste-specific phenotypes, during the molts of each caste; workers, soldiers, presoldiers (intermediate stage of soldiers), and alates (primary reproductives) in Zootermopsis nevadensis. Expression patterns of cuticular tanning genes (members of the tyrosine metabolic pathway) were different among each molt, and high expression levels of several "key genes" were observed during each caste differentiation. For the differentiation of castes with well-tanned cuticles (i.e. soldiers and alates), all focal genes except DDC in the former were highly expressed. On the other hand, high expression levels of yellow and aaNAT were observed during worker and presoldier molts, respectively, but most other genes in the pathway were expressed at low levels. RNA interference (RNAi) of these key genes affected caste-specific cuticular pigmentation, leading to soldiers with yellowish-white heads and pigmented mandibular tips, presoldiers with partly pigmented head cuticles, and alates with the yellow head capsules. These results suggest that the pigmentation of caste-specific cuticles is achieved by the regulation of gene expression in the tyrosine metabolic pathway. PMID:27125584

  7. Differential Reinforcement of Communicative Behaviors (DRC): An Intervention for the Disruptive Behaviors of Developmentally Disabled Children.

    Science.gov (United States)

    Durand, V. Mark; Carr, Edward G.

    A study, involving four developmentally disabled children who exhibited a variety of disruptive behaviors such as self-injury and tantrums, was conducted to assess the influence of task demands and adult attention on children's behaviors. The three experimental conditions were the "EASY 100" which consisted of an easy task on which children could…

  8. Environmental Influences on Genetic Expression: Biological and Behavioral Aspects of Sexual Differentiation.

    Science.gov (United States)

    Kretchmer, Norman, Ed.; Walcher, Dwain N., Ed.

    A cross-disciplinary approach to the topic of sexual differentiation comprises this volume. Diverse papers are included under a variety of headings: 1) critical Periods in development; 2) embryology; 3) RNA-DNA; 4) chromosomes-growth and development; 5) physiology; 6) primates; 7) cognition; 8) cultural differences in patterns of sexual behavior;…

  9. Differential Effects of Reinforcement on the Self-Monitoring of On-Task Behavior

    Science.gov (United States)

    Otero, Tiffany L.; Haut, Jillian M.

    2016-01-01

    In the current study, the differential effects of reinforcement on a self-monitoring intervention were evaluated. Three students nominated by their teachers for having a marked difficultly maintaining on-task behaviors participated in the study. Using an alternating treatments single-case design to assess self-monitoring with and without…

  10. ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO SECOND ORDER IMPULSIVE DIFFERENTIAL EQUATION ON TIME SCALES

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper,we investigate a second order impulsive differential equation on time scales.Sufficient conditions are given to guarantee that the solutions tend to zero.The notable effect of impulse upon the asymptotic behavior of solutions is stressed in this paper.At last,we illustrate our results with two examples.

  11. Do Guilt- and Shame-Proneness Differentially Predict Prosocial, Aggressive, and Withdrawn Behaviors during Early Adolescence?

    Science.gov (United States)

    Roos, Sanna; Hodges, Ernest V. E.; Salmivalli, Christina

    2014-01-01

    In this short-term longitudinal study, we systematically examined the distinctiveness of guilt- and shame-proneness in early adolescents (N = 395, mean age = 11.8 years) in terms of differential relations with peer reported prosocial behavior, withdrawal, and aggression. Results from structural equation modeling indicated that guilt-proneness…

  12. Parental anxiety, parenting behavior, and infant anxiety: differential associations for fathers and mothers

    NARCIS (Netherlands)

    E.L. Möller; M. Majdandžić; S.M. Bögels

    2014-01-01

    Most studies investigating the role of parenting behavior in the intergenerational transmission of anxiety from parents to children have focused on mothers. However, recent research suggests that mothers and fathers may parent differently and may differentially affect the development of child anxiet

  13. Variable Differential Reinforcement of Other Behavior (VDRO): Its Effectiveness as a Modification Procedure.

    Science.gov (United States)

    Reuter, Katherine E.; LeBlanc, Judith M.

    Two groups of five preschool children were trained to press a key for marbles for four sessions of variable ratio reinforcement (VR6). Subsequently, response decrement for the groups was compared during conditions of fixed and variable differential reinforcement of other behavior (DRO and VDRO). Fixed DRO was more effective for decreasing response…

  14. Differential negative reinforcement of other behavior to increase wearing of a medical bracelet.

    Science.gov (United States)

    Cook, Jennifer L; Rapp, John T; Schulze, Kimberley A

    2015-12-01

    We used a changing criterion design to evaluate the extent to which differential negative reinforcement of other behavior increased compliance with wearing a medical alert bracelet for a young boy with autism. Results showed the duration for which the participant wore the bracelet systematically increased across trials from 5 s to 7 hr over several weeks.

  15. Microstructure and Wear Behavior of TiC Coating Deposited on Spheroidized Graphite Cast Iron Using Laser Surfacing

    Directory of Open Access Journals (Sweden)

    E. R. I. Mahmoud

    2014-10-01

    Full Text Available Spheroidal graphite cast iron was laser cladded with TiC powder using a YAG fiber laser at powers of 700, 1000, 1500 and 2000 W. The powder was preplaced on the surface of the specimens with 0.5 mm thickness. Sound cladding and fusion zones were observed at 700, 1000 and 1500 W powers. However, at 2000 W, cracking was observed in the fusion zone. At 700 W, a build-up zone consisted of fine TiC dendrites inside a matrix composed of martensite, cementite (Fe3C, and some blocks of retained austenite was observed. In this zone, all graphite nodules were totally melted. In the fusion zone, some undissolved and partially dissolved graphite nodules appeared in a matrix containing bainite, ferrite, martensite and retained austenite. At 1500 W, the fusion zone had more iron carbides and ferrite, and the HAZ consisted of martensitic structure. At 2000 W, the build-up zone was consisted of TiC particles precipitated in a matrix of eutectic carbides, martensite plus an inter-lamellar retained austenite. The hardness of the cladded area was remarkably improved (1330 HV in case of 700 W: 5.5 times of the hardness of substrate

  16. Effect of Cu, Zn, and Mg Concentration on Heat Treating Behavior of Squeeze Cast Al-(10 to 12Zn-(3.0 to 3.4Mg-(0.8 to 1Cu

    Directory of Open Access Journals (Sweden)

    J.B. Ferguson

    2014-06-01

    Full Text Available Aluminum Alloy AA-7034 is a high strength wrought alloy with reasonable ductility containing 10–12 wt% Zn, 2–3 wt% Mg, and 0.8–1.2 wt% Cu. This work investigates the effect of varying the concentration of Zn (10–12 wt% and Cu (0.8–1 wt% on the solutionizing and aging behavior of squeeze cast AA-7034 samples. The same behaviors were investigated when Mg content was increased beyond 3 wt%. The solutionizing heat treatment dissolved much of the macroscopic second phases present in the as-cast AA-7034 alloys, but a significant amount of second phases remain after solutionizing in alloys with >3 wt% Mg. The behaviors of the various Al-Zn-Mg-Cu alloys are compared to squeeze cast Al-A206 casting alloy heat-treated to the T7 condition. All Al-Zn-Mg-Cu alloys obtained higher hardness values than those obtained by Al-A206-T7.

  17. Differential Reinforcement of Alternative Behavior Increases Resistance to Extinction: Clinical Demonstration, Animal Modeling, and Clinical Test of One Solution

    Science.gov (United States)

    Mace, F. Charles; McComas, Jennifer J.; Mauro, Benjamin C.; Progar, Patrick R.; Taylor, Bridget; Ervin, Ruth; Zangrillo, Amanda N.

    2010-01-01

    Basic research with pigeons on behavioral momentum suggests that differential reinforcement of alternative behavior (DRA) can increase the resistance of target behavior to change. This finding suggests that clinical applications of DRA may inadvertently increase the persistence of target behavior even as it decreases its frequency. We conducted…

  18. Differential pathways of positive and negative health behavior change in congestive heart failure patients.

    Science.gov (United States)

    Chaves, Covadonga; Park, Crystal L

    2016-08-01

    This longitudinal study applied a stress and coping model to examine the differential pathways of perceived positive and negative health behavior changes. Participants with congestive heart failure completed self-report measures of psychological resources, coping strategies, and perceived behavior changes and were assessed again 6 months later. Patients with higher positive affect and spiritual well-being reported more positive health behavior changes over time, effects mediated by approach coping. Alternatively, patients with lower psychological resources reported more negative behavior changes over time, effects mediated by avoidance coping. The results suggest that different psychological resources are related to different types of coping which, in turn, are associated with perceived positive or negative changes in health behavior over time.

  19. Tachykinin expression levels correlate with caste-specific aggression in workers of the leaf-cutting ant Acromyrmex echinatior

    Directory of Open Access Journals (Sweden)

    Jack eHowe

    2016-05-01

    Full Text Available The tachykinins are a family of neuropeptides that influence a range of behavioral phenotypes in both vertebrates and invertebrates; they appear to have a conserved role in the processing of stimuli, and in the control of aggression in a wide range of animals. Expression of tachykinin in a cluster of neurons was recently shown to determine the stimulus response threshold for aggressive behavior in Drosophila (1. Varying response thresholds are often implicated in division of labor within social insect colonies, so we hypothesized that Tachykinin could play a role in the organization of colony defense by affecting individual response thresholds to non-nestmate stimuli. We used quantitative-PCR in combination with behavioral assays to test for associations between the expression of Tachykinin and its receptor, and the aggressive division of labor among the castes of the leaf-cutting ant Acromyrmex echinatior, a species with multiple worker castes. After correction for differences in brain size among castes, we found that the most aggressive large worker caste had the highest Tachykinin expression levels, but that no such effect was apparent for breeding and virgin queens. To further evaluate these deviating results for the reproductive caste, we manipulated the aggression threshold of virgin-queens by removing their wings, which is known to make them express a soldier-like behavioral phenotype. Despite heightened aggression, expression levels of Tachykinin remained unaffected, suggesting that aggression levels in reproductive caste phenotypes are controlled by differential expression of other genes.

  20. Influence of neodymium addition on microstructure, tensile properties and fracture behavior of cast AI-Mg2Si metal matrix composite

    Institute of Scientific and Technical Information of China (English)

    WU Xiaofeng; ZHANG Guang'an; WU Fufa; WANG Zhe

    2013-01-01

    The influence of Nd on the microstructures,tensile properties and fracture behavior of cast Al-18 wt.%MgaSi in situ metal matrix composite was investigated.Experimental results showed that,after introducing a proper amount of Nd,both primary and eutectic Mg2Si in the Al-18 wt.%Mg2Si composite were well modified.The morphology of primary Mg2Si was changed from irregular or dendritic to polyhedral shape,and its average particle size was significantly decreased from 47.5 to 13.0 μm.Moreover,the morphology of the eutectic Mg2Si phase was altered from flake-like to a thin laminar,short fibrous or dot-like structure.Tensile tests revealed that Nd addition improved the tensile strength and ductility of the material.Compared with those of unmodified composite,the ultimate tensile strength and percentage elongation with 0.5% Nd were increased by 32.4% and 200%,respectively.At the same time,Nd addition changed the fracture behavior from brittle to ductile.

  1. The UK Casting Industry

    Institute of Scientific and Technical Information of China (English)

    Jincheng Liu

    2006-01-01

    The casting production in the UK in 2004 is presented and analysed. The UK casting industry has played an important role in world casting and manufacturing production. However recent years the rapid development of some developing countries has been shifting the casting production from the western industrialized countries including the UK. The UK casting industry and associated research and technology organizations, universities have been working together very hard to face the serious competition to make the UK casting industry have a sustainable future. The UK casting industry remains strong and plays an important role in world casting and manufacturing production.

  2. CA Investment Casting Process of Complex Castings

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CA (Computer aided) investment casting technique used in superalloy castings of aerospace engine parts was presented. CA investment casting integrated computer application, RP (Rapid Prototyping) process, solidification simulation and investment casting process. It broke the bottle neck of making metal die. Solid model of complex parts were produced by UGII or other software, then translated into STL(Stereolithography) file, after RP process of SLS(Selective Laser Sintering), wax pattern used in investment ...

  3. Evidence for phase transitional behavior of even-even nuclei from differential observables

    International Nuclear Information System (INIS)

    Following recent discussions of critical phase transitional behavior of nuclei, additional data are collected and used to test if there is further evidence supporting such phenomena. Data from nuclear masses, radii, and E2 transition rates are used to construct differential observables. Inspection of these for the rare earth region shows that they exhibit the characteristic phase transitional behavior found in condensed matter and thermodynamic systems, namely, nearly constant values before the critical point, and a sharp change in the critical region, followed by a different set of values after the critical point

  4. Differential Reinforcement of Alternative Behavior Increases Resistance to Extinction: Clinical Demonstration, Animal Modeling, and Clinical Test of One Solution

    OpenAIRE

    Mace, F. Charles; McComas, Jennifer J; Mauro, Benjamin C.; Progar, Patrick R; Taylor, Bridget; Ervin, Ruth; Zangrillo, Amanda N

    2010-01-01

    Basic research with pigeons on behavioral momentum suggests that differential reinforcement of alternative behavior (DRA) can increase the resistance of target behavior to change. This finding suggests that clinical applications of DRA may inadvertently increase the persistence of target behavior even as it decreases its frequency. We conducted three coordinated experiments to test whether DRA has persistence-strengthening effects on clinically significant target behavior and then tested the ...

  5. Evaluation of behavior of biodegradable lubricants in the differential sticking coefficient of water based drilling fluids

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, L.V. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais], E-mail: luciana@dem.ufcg.edu.br; Nascimento, R.C.A.M. [Universidade Federal de Campina Grande (PPGCEMat/UFCG), PB (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Lira, D.S. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia Quimica; Magalhaes, J. [System Mud Fluidos de Perfuracao, Itajai, SC (Brazil). Dept. de Quimica

    2011-10-15

    This work aims to evaluate the behavior of four samples of biodegradable lubricants in the differential sticking coefficient of aqueous drilling fluids. Eighteen formulations of fluids containing bentonite clay, lubricants and biodegradable polymers in different concentrations were studied. The experiment focused on observing the samples' rheological properties, its filtration, the cake thickness, the lubricity coefficient, and, finally, the coefficient of the differential sticking. The results showed that the polymer additives improved rheological and filtration properties significantly. Also, the findings confirmed the idea that the presence of a lubricant leads to a reduction in lubricity, LC, and affects the differential sticking coefficient, DSC, of the fluids. However, the experiment observed a small variation on the LC as a result of an increase in the lubricant content. Overall, the results of the LC and the DSC of the fluids containing biodegradable lubricant additives were outstanding, being similar to the ones observed for oil-based fluids. (author)

  6. Gating of Permanent Molds for ALuminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  7. The effects of extinction, noncontingent reinforcement and differential reinforcement of other behavior as control procedures.

    OpenAIRE

    Thompson, Rachel H; Iwata, Brian A; Hanley, Gregory P; Dozier, Claudia L; Samaha, Andrew L

    2003-01-01

    Several techniques have been used in applied research as controls for the introduction of a reinforcement contingency, including extinction, noncontingent reinforcement (NCR), and differential reinforcement of other behavior (DRO). Little research, however, has examined the relative strengths and limitations of these "reversal" controls. We compared the effects of extinction with those of NCR and DRO in both multi-element and reversal designs, with respect to (a) rate and amount of response d...

  8. ASYMPTOTIC BEHAVIOR OF MULTISTEP RUNGE-KUTTA METHODS FOR SYSTEMS OF DELAY DIFFERENTIAL EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    张诚坚; 廖晓昕

    2001-01-01

    This paper deals with the asymptotic behavior of multistep Runge-Kutta methods for systems of delay differential equations (DDEs). With the help of K.J.in't Hout's analytic technique for the numerical stability of onestep Runge-Kutta methods, we obtain that a multistep Runge-Kutta method for DDEs is stable iff the corresponding methods for ODEs is A-stable under suitable interpolation conditions.

  9. Effects of alloying elements on nitrogen diffusion behavior around TiN/Ti interface α region in as-cast titanium alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To characterize the effects of alloying elements on inclusion dissolution of titanium nitride, the content profiles of elements around TiN/Ti boundary α phase regions in liquid titanium alloys have been experimentally carried out. Four kinds of commercial alloys of CpTi, Ti64, Ti17 and Ti6242 containing different α-stabilizing or β-stabilizing elements are examined through artificially embedding the TiN sponge particle into liquid alloys in VAR conditions. The content profiles of nitrogen and alloying elements around TiN/Ti boundary were measured by WDX and microprobe for as-cast samples. The content profiles of nitrogen and alloying elements around N-containing solid in αTi region of these alloys show a common features of a steep change. In particular, the content profiles of elements for Ti6242 demonstrate unique change of a more gentle change tendency and further deeper into the alloy matrix. The experiment results show that, the differences among composite effects of alloying elements in different alloys within nitrogen-induced diffusion α region result in different dissolution and diffusion behaviors to overcome the α phase region barriers.

  10. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17%Cr and Cu-17%Cr-5%Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj. Sai V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu- 17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9 9.5 kJ mol-1. In contrast, the oxidation kinetics for the Cu-17%Cr- 5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR- 5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  11. Comparison of the Isothermal Oxidation Behavior of As-Cast Cu-17 Percent Cr and Cu-17 Percent Cr-5 Percent Al. Part 1; Oxidation Kinetics

    Science.gov (United States)

    Raj, S. V.

    2008-01-01

    The isothermal oxidation kinetics of as-cast Cu-17%Cr and Cu-17%Cr-5%Al in air were studied between 773 and 1173 K under atmospheric pressure. These observations reveal that Cu-17%Cr-5%Al oxidizes at significantly slower rates than Cu-17%Cr. The rate constants for the alloys were determined from generalized analyses of the data without an a priori assumption of the nature of the oxidation kinetics. Detailed analyses of the isothermal thermogravimetric weight change data revealed that Cu-17%Cr exhibited parabolic oxidation kinetics with an activation energy of 165.9+/-9.5 kJ/mol. In contrast, the oxidation kinetics for the Cu-17%Cr-5%Al alloy exhibited a parabolic oxidation kinetics during the initial stages followed by a quartic relationship in the later stages of oxidation. Alternatively, the oxidation behavior of Cu-17%CR-5%Al could be better represented by a logarithmic relationship. The parabolic rate constants and activation energy data for the two alloys are compared with literature data to gain insights on the nature of the oxidation mechanisms dominant in these alloys.

  12. Separate and Combined Effects of Visual Schedules and Extinction Plus Differential Reinforcement on Problem Behavior Occasioned by Transitions

    Science.gov (United States)

    Waters, Melissa B.; Lerman, Dorothea C.; Hovanetz, Alyson N.

    2009-01-01

    The separate and combined effects of visual schedules and extinction plus differential reinforcement of other behavior (DRO) were evaluated to decrease transition-related problem behavior of 2 children diagnosed with autism. Visual schedules alone were ineffective in reducing problem behavior when transitioning from preferred to nonpreferred…

  13. The ancient Chinese casting techniques

    OpenAIRE

    Tan Derui; Lian Haiping

    2011-01-01

    In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast ir...

  14. Special thermite cast irons

    OpenAIRE

    Yu. Zhiguts; I. Kurytnik

    2008-01-01

    The given paper deals with the problems of the synthesis of cast iron by metallothermy synthesis. On the basis of investigated method of calculations structures of charges have been arranged and cast iron has been synthesized further. Peculiarities metallothermic smelting were found, mechanical properties and structure of received cast iron were investigated and different technologies for cast iron receiving were worked out.

  15. Differential regulation of the foraging gene associated with task behaviors in harvester ants

    Directory of Open Access Journals (Sweden)

    Kleeman Lindsay

    2011-08-01

    Full Text Available Abstract Background The division of labor in social insect colonies involves transitions by workers from one task to another and is critical to the organization and ecological success of colonies. The differential regulation of genetic pathways is likely to be a key mechanism involved in plasticity of social insect task behavior. One of the few pathways implicated in social organization involves the cGMP-activated protein kinase gene, foraging, a gene associated with foraging behavior in social insect species. The association of the foraging gene with behavior is conserved across diverse species, but the observed expression patterns and proposed functions of this gene vary across taxa. We compared the protein sequence of foraging across social insects and explored whether the differential regulation of this gene is associated with task behaviors in the harvester ant, Pogonomyrmex occidentalis. Results Phylogenetic analysis of the coding region of the foraging gene reveals considerable conservation in protein sequence across insects, particularly among hymenopteran species. The absence of amino acid variation in key active and binding sites suggests that differences in behaviors associated with this gene among species may be the result of changes in gene expression rather than gene divergence. Using real time qPCR analyses with a harvester ant ortholog to foraging (Pofor, we found that the brains of harvester ant foragers have a daily fluctuation in expression of foraging with mRNA levels peaking at midday. In contrast, young workers inside the nest have low levels of Pofor mRNA with no evidence of daily fluctuations in expression. As a result, the association of foraging expression with task behavior within a species changes depending on the time of day the individuals are sampled. Conclusions The amino acid protein sequence of foraging is highly conserved across social insects. Differences in foraging behaviors associated with this gene among

  16. Understanding of the influence of process parameters on the heat transfer behavior at the metal/die inter-face in high pressure die casting process

    Institute of Scientific and Technical Information of China (English)

    GUO ZhiPeng; XIONG ShouMei; LIU BaiCheng; LI Mei; Allison John

    2009-01-01

    The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IHTC) at metal/die interface during high pressure die casting (HPDC) process. A "step shape" casting and AM50 alloy were used during the experiment. The IHTC was de-termined by solving the inverse thermal problem based on the measured temperature inside the die. Results show that the initial die surface temperature (IDST, TDI) has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values. By curve fitting, it was found that the IHTC peak value (hmax) changes as a function of the IDST in a manner of hmax=eαTγDI. Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12, indicating that this phenomenon is a common characteristic in the HPDC process.

  17. Research on strain fatigue behavior of ZG20SiMn cast steel%ZG20SiMn 铸钢的应变疲劳行为研究

    Institute of Scientific and Technical Information of China (English)

    李媛媛; 车欣; 李锋; 陈立佳

    2014-01-01

    为了深入理解 ZG20SiMn 铸钢在应变疲劳期间的循环变形及断裂行为,在应变控制模式下针对 ZG20SiMn 铸钢的疲劳行为进行了研究。结果表明,在应变控制的加载模式下,ZG20SiMn铸钢可表现为循环硬化和循环稳定特征,主要取决于外加总应变幅的高低,且其弹性应变幅、塑性应变幅与疲劳断裂时的载荷反向周次之间表现为单斜率线性行为。透射电镜分析结果表明, ZG20SiMn 的疲劳变形机制主要为波状滑移机制。扫描电镜分析结果表明,在不同的外加总应变幅下,疲劳裂纹均以穿晶方式萌生于 ZG20SiMn 铸钢试样表面,并以穿晶方式扩展。%In order to understand the cyclic deformation and fracture behaviors of ZG20SiMn cast steel,the fatigue behavior of ZG20SiMn cast steel was investigared under the strain-controlled mode.The experimental results show that under the strain-controlled loading mode,the ZG20SiMn cast steel can exhibit the cyclic strain hardening and cyclic stability,which mainly depends on the imposed total strain amplitude.For the ZG20SiMn cast steel,the relation between the reversals to failure and the elastic strain amplitude or plastic strain amplitude shows a single slope of linear behavior,respectively.The analysis results with transmission electron microscope (TEM)reveal that the fatigue deformation mechanism of ZG20SiMn cast steel is the wavy slip mechanism.The analysis results on the fatigue fracture surfaces of ZG20SiMn cast steel with scanning electron microscope (SEM)reveal that at different total strain amplitudes,the fatigue cracks initiate at the free surface of fatgiue specimen in a transgranular mode,and then propagate in a transgranular mode.

  18. Standard digital reference images for titanium castings

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 The digital reference images provided in the adjunct to this standard illustrate various types and degrees of discontinuities occurring in titanium castings. Use of this standard for the specification or grading of castings requires procurement of the adjunct digital reference images, which illustrate the discontinuity types and severity levels. They are intended to provide the following: 1.1.1 A guide enabling recognition of titanium casting discontinuities and their differentiation both as to type and degree through digital radiographic examination. 1.1.2 Example digital radiographic illustrations of discontinuities and a nomenclature for reference in acceptance standards, specifications and drawings. 1.2 The digital reference images consist of seventeen digital files each illustrating eight grades of increasing severity. The files illustrate seven common discontinuity types representing casting sections up to 1-in. (25.4-mm). 1.3 The reference radiographs were developed for casting sections up to 1...

  19. Maternal reflective functioning as a multidimensional construct: Differential associations with children's temperament and externalizing behavior.

    Science.gov (United States)

    Smaling, H J A; Huijbregts, S C J; van der Heijden, K B; van Goozen, S H M; Swaab, H

    2016-08-01

    Maternal reflective functioning (RF) has been associated with children's behavioral development. This study examined maternal prenatal and postnatal RF, as measured by the Pregnancy Interview and Parent Development Interview, as multidimensional constructs. It was also examined whether the RF-dimensions were associated with children's temperament and externalizing behavior, as assessed by several questionnaires. The sample consisted of 123 first-time mothers (M age=22.85years, SD=2.21) and their children (M age=19.97months, SD=0.85, 56% male). Two related but distinct dimensions were found for prenatal RF, termed self-focused and child-focused mentalization. Three dimensions were observed for postnatal RF, termed self-focused, child-focused, and relation-focused mentalization. Results showed that prenatal RF negatively related to reported child physical aggression. Postnatal self-focused RF was positively linked to externalizing behavior and negative emotionality in offspring, while relation-focused RF scores were negatively associated with child physical aggression. Findings show that it is important to also look at the specific RF-dimensions when examining the effects of maternal RF on children's behavioral development, as differential associations with behavioral outcomes exist. Discussion further focuses on the importance of these findings in prevention and clinical practice, and suggestions are being made to further improve the measurement of maternal RF-dimensions. PMID:27522031

  20. Differential hedonic experience and behavioral activation in schizophrenia and bipolar disorder.

    Science.gov (United States)

    Tso, Ivy F; Grove, Tyler B; Taylor, Stephan F

    2014-11-30

    The Kraepelinian distinction between schizophrenia (SZ) and bipolar disorder (BP) emphasizes affective and volitional impairment in the former, but data directly comparing the two disorders for hedonic experience are scarce. This study examined whether hedonic experience and behavioral activation may be useful phenotypes distinguishing SZ and BP. Participants were 39 SZ and 24 BP patients without current mood episode matched for demographics and negative affect, along with 36 healthy controls (HC). They completed the Chapman Physical and Social Anhedonia Scales, Temporal Experience of Pleasure Scale (TEPS), and Behavioral Activation Scale (BAS). SZ and BP showed equally elevated levels of self-report negative affect and trait anhedonia compared to HC. However, SZ reported significantly lower pleasure experience (TEPS) and behavioral activation (BAS) than BP, who did not differ from HC. SZ and BP showed differential patterns of relationships between the hedonic experience and behavioral activation measures. Overall, the results suggest that reduced hedonic experience and behavioral activation may be effective phenotypes distinguishing SZ from BP even when affective symptoms are minimal. However, hedonic experience differences between SZ and BP are sensitive to measurement strategy, calling for further research on the nature of anhedonia and its relation to motivation in these disorders. PMID:24999173

  1. Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route

    Directory of Open Access Journals (Sweden)

    Yoshihiko Hangai

    2014-03-01

    Full Text Available Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.

  2. Asymptotic behavior of solutions for some nonlinear partial differential equations on unbounded domains

    Directory of Open Access Journals (Sweden)

    Jacqueline Fleckinger

    2001-12-01

    Full Text Available We study the asymptotic behavior of positive solutions $u$ of $$ -Delta_p u(x = V(x u(x^{p-1}, quad p>1; x in Omega,$$ and related partial differential inequalities, as well as conditions for existence of such solutions. Here, $Omega$ contains the exterior of a ball in $mathbb{R}^N$ $1

  3. Emergent user behavior on Twitter modelled by a stochastic differential equation

    CERN Document Server

    Mollgaard, Anders

    2015-01-01

    Data from the social-media site, Twitter, is used to study the fluctuations in tweet rates of brand names. The tweet rates are the result of a strongly correlated user behavior, which leads to bursty collective dynamics with a characteristic 1/f noise. Here we use the aggregated "user interest" in a brand name to model collective human dynamics by a stochastic differential equation with multiplicative noise. The model is supported by a detailed analysis of the tweet rate fluctuations and it reproduces both the exact bursty dynamics found in the data and the 1/f noise.

  4. Emergent user behavior on Twitter modelled by a stochastic differential equation.

    Science.gov (United States)

    Mollgaard, Anders; Mathiesen, Joachim

    2015-01-01

    Data from the social-media site, Twitter, is used to study the fluctuations in tweet rates of brand names. The tweet rates are the result of a strongly correlated user behavior, which leads to bursty collective dynamics with a characteristic 1/f noise. Here we use the aggregated "user interest" in a brand name to model collective human dynamics by a stochastic differential equation with multiplicative noise. The model is supported by a detailed analysis of the tweet rate fluctuations and it reproduces both the exact bursty dynamics found in the data and the 1/f noise.

  5. Emergent user behavior on Twitter modelled by a stochastic differential equation.

    Directory of Open Access Journals (Sweden)

    Anders Mollgaard

    Full Text Available Data from the social-media site, Twitter, is used to study the fluctuations in tweet rates of brand names. The tweet rates are the result of a strongly correlated user behavior, which leads to bursty collective dynamics with a characteristic 1/f noise. Here we use the aggregated "user interest" in a brand name to model collective human dynamics by a stochastic differential equation with multiplicative noise. The model is supported by a detailed analysis of the tweet rate fluctuations and it reproduces both the exact bursty dynamics found in the data and the 1/f noise.

  6. Negative differential resistance behavior in phosphorus-doped armchair graphene nanoribbon junctions

    International Nuclear Information System (INIS)

    In this present work, we investigate the electronic transport properties of phosphorus-doped armchair graphene nanoribbon (AGNR) junctions by employing nonequilibrium Green's functions in combination with the density-function theory. Two phosphorus (P) atoms are considered to substitute the central carbon atom with the different width of AGNRs. The results indicate that the electronic transport behaviors are strongly dependent on the width of the P-doped graphene nanoribbons. The current-voltage characteristics of the doped AGNR junctions reveal an interesting negative differential resistance (NDR) and exhibit three distinct family (3 n, 3 n + 1, 3 n + 2) behaviors. These results display that P doping is a very good way to achieve NDR of the graphene nanoribbon devices

  7. Consistent Differential Expression Pattern (CDEP on microarray to identify genes related to metastatic behavior

    Directory of Open Access Journals (Sweden)

    Tsoi Lam C

    2011-11-01

    Full Text Available Abstract Background To utilize the large volume of gene expression information generated from different microarray experiments, several meta-analysis techniques have been developed. Despite these efforts, there remain significant challenges to effectively increasing the statistical power and decreasing the Type I error rate while pooling the heterogeneous datasets from public resources. The objective of this study is to develop a novel meta-analysis approach, Consistent Differential Expression Pattern (CDEP, to identify genes with common differential expression patterns across different datasets. Results We combined False Discovery Rate (FDR estimation and the non-parametric RankProd approach to estimate the Type I error rate in each microarray dataset of the meta-analysis. These Type I error rates from all datasets were then used to identify genes with common differential expression patterns. Our simulation study showed that CDEP achieved higher statistical power and maintained low Type I error rate when compared with two recently proposed meta-analysis approaches. We applied CDEP to analyze microarray data from different laboratories that compared transcription profiles between metastatic and primary cancer of different types. Many genes identified as differentially expressed consistently across different cancer types are in pathways related to metastatic behavior, such as ECM-receptor interaction, focal adhesion, and blood vessel development. We also identified novel genes such as AMIGO2, Gem, and CXCL11 that have not been shown to associate with, but may play roles in, metastasis. Conclusions CDEP is a flexible approach that borrows information from each dataset in a meta-analysis in order to identify genes being differentially expressed consistently. We have shown that CDEP can gain higher statistical power than other existing approaches under a variety of settings considered in the simulation study, suggesting its robustness and

  8. Exploring behaviors of stochastic differential equation models of biological systems using change of measures

    Directory of Open Access Journals (Sweden)

    Jha Sumit

    2012-04-01

    Full Text Available Abstract Stochastic Differential Equations (SDE are often used to model the stochastic dynamics of biological systems. Unfortunately, rare but biologically interesting behaviors (e.g., oncogenesis can be difficult to observe in stochastic models. Consequently, the analysis of behaviors of SDE models using numerical simulations can be challenging. We introduce a method for solving the following problem: given a SDE model and a high-level behavioral specification about the dynamics of the model, algorithmically decide whether the model satisfies the specification. While there are a number of techniques for addressing this problem for discrete-state stochastic models, the analysis of SDE and other continuous-state models has received less attention. Our proposed solution uses a combination of Bayesian sequential hypothesis testing, non-identically distributed samples, and Girsanov's theorem for change of measures to examine rare behaviors. We use our algorithm to analyze two SDE models of tumor dynamics. Our use of non-identically distributed samples sampling contributes to the state of the art in statistical verification and model checking of stochastic models by providing an effective means for exposing rare events in SDEs, while retaining the ability to compute bounds on the probability that those events occur.

  9. Differential trajectories of alcohol-related behaviors across the first year of college by parenting profiles.

    Science.gov (United States)

    Abar, Caitlin C; Turrisi, Robert J; Mallett, Kimberly A

    2014-03-01

    This study examined the extent to which profiles of perceived parenting are associated with trajectories of alcohol-related behaviors across the first year of college. Participants were surveyed five times from the summer before college to the fall of the second year. A total 285 college students were enrolled from the incoming classes of consecutive cohorts of students at a large, public university in the Northeastern United States. At baseline, participants provided information on their parents' alcohol-related behaviors (e.g., parental modeling of use; perceived approval of underage use) and parenting characteristics (e.g., parental monitoring; parent-child relationship quality). Students also reported on their personal alcohol-related behaviors at each time point. Latent profile analysis was used to identify four subgroups based on the set of parenting characteristics: High Quality (14%) - highest parent-teen relationship quality; High Monitoring (31%) - highest parental monitoring and knowledge; Low Involvement (30%) - poor relationship quality, little monitoring and communication; and Pro-Alcohol (21%) - highest parental modeling and approval. Students were then assigned to profiles, and their alcohol-related behaviors were examined longitudinally using latent growth curve modeling. In general, students in the Pro-Alcohol profile displayed the highest baseline levels of typical weekend drinking, heavy episodic drinking, and peak blood alcohol content, in addition to showing steeper increases in typical weekend drinking across the first year of college. Results support the notion that parental behaviors remain relevant across the first year of college. Differential alcohol-related behaviors across parenting profiles highlight the potential for tailored college intervention. PMID:23915366

  10. Hot Extrusion Process Effect on Mechanical Behavior of Stir Cast Al Based Composites Reinforced with Mechanically Milled B4C Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    A. Alizadeh1; E. Taheri-Nassaj; M. Hajizamani

    2011-01-01

    In this study, aluminum alloy (Al-2 wt% Cu) matrix composites reinforced with 1, 2 and 4 wt% boron carbide nanoparticles fabricated through mechanical milling with average size of 100 nm were fabricated via stir casting method at 850℃. Cast ingots of the matrix alloy and the composites were extruded at 500℃ at an extrusion ratio of 10:1 to investigate the effects of hot extrusion on the mechanical properties of the composites. The microstructures of the as-cast and the extruded composites were investigated by scanning electron microscopy (SEM). Density measurement, hardness and tensile tests were carried out to identify the mechanical properties of the composites. The extruded samples revealed a more uniform distribution of B4C nanoparticles. Also, the extruded samples had strength and ductility values superior to those of the as-cast counterparts. In the as-cast and the extruded samples, with increasing amount of B4C nanoparticles, yield strength and tensile strength increased but elongation to fracture decreased.

  11. Influence of Pressure and Temperature on Microstructure and Mechanical Behavior of Squeeze Cast Mg-10Gd-3Y-0.5Zr Alloy

    Science.gov (United States)

    Wang, Cunlong; Lavernia, Enrique J.; Wu, Guohua; Liu, Wencai; Ding, Wenjiang

    2016-08-01

    The influence of applied pressure and pouring temperature on the microstructure and mechanical properties of a squeeze cast (SC) Mg-10Gd-3Y-0.5Zr (GW103K) alloy was systematically investigated. Our results show that increasing the applied pressure leads to microstructure refinement of the GW103K alloy with accompanying enhancement of tensile yield strength (TYS), ultimate tensile strength (UTS), and elongation to failure ( E f); a decrease in pouring temperature also leads to grain refinement and increases of TYS while decreasing the UTS and E f. Our results show that, for the range of parameters studied herein, an applied pressure of ~160 MPa, in combination with a pouring temperature of ~993 K (720 °C), represents optimum process parameters for squeeze casting of GW103K. Using these process parameters, the TYS, UTS, and E f of squeeze cast GW103K alloy are 151 MPa, 232 MPa, and 3.0 pct in the as-cast state, and 264 MPa, 383 MPa, and 1.5 pct, respectively, in the as-T6 heat-treated state, both of which represent significant improvements over those of the gravity cast (GC) counterpart material.

  12. Relationship between phenotypes of cell-function differentiation and pathobiological behavior of gastric carcinomas

    Institute of Scientific and Technical Information of China (English)

    Yan Xin; Xiao Ling Li; Yan Ping Wang; Su Min Zhang; Hua Chuan Zheng; Dong Ying Wu; Yin Chang Zhang

    2001-01-01

    AIM To reveal the correlation between thefunctional differentiation phenotypes of gastriccarcinoma cells and the invasion and metastasisby a new way of cell-function classification.METHODS Surgically resected specimens of361 gastric carcinomas (GC) were investigatedwith enzyme-, mucin-, and tumor-related markerimmunohistochemist ry. According to thedirection of cell-function differentiation,stomach carcinomas were divided into fivefunctionally differentiated types.iation type (AFDT): there were 82 (22.7%)patients including 76 (92.7%) aged 45 years.Sixty-nine (84.1%) cases belonged to theintestinal type. Thirty-eight (46.3%) expressedCD44v6 and 9 (13.6%) of 66 male patientsdeveloped liver metastasis. The 5-year survivalrate of patients in this group (58.5%) was higherMucin secreting function differentiation type(MSFDT): 54 (15%) cases. Fifty-three (98.1%)tumors had penetrated the serosa, 12 (22.2%)expressed ER and 22 (40.7%) expressedCD44v6. The postoperative 5-year survival ratefunction differentiation type (AMPFDT): therewere 180 (49.9%) cases, including 31 (17.2%)aged yanger than 45 years. The tumor was morecommon in women (62, 34.4%,) and expressedmore frequently estrogen receptors (ER) ( 129,81.7%) than other types (P<0.01). Ovarymetastasis was found in 12 (19.4%) out of 62female subjects. The patients with this type GChad the lowest 5-year survival rate (24.7%)differentiation type (SFDT): 13 (3.6%) cases.Nine (69.2%) tumors of this type derived fromAPUD system, the other 4 (30.7%) were ofdifferent histological differentiation. Sixty percent of the patients survived at least five years.(8.9%) cases. Nineteen (59.4%) cases hadlymph node metastases but no one with liver orovary metastasis. The 5-year survival rate was28.1%.CONCLUSION This new cell-functionclassification of GC is helpful in indicating thecharacteristics of invasion and metastasis of GCwith different cell-function differentiationphenotypes. Further study is needed to disclosethe correlation

  13. Plastic casting resin poisoning

    Science.gov (United States)

    Epoxy poisoning; Resin poisoning ... Epoxy and resin can be poisonous if they are swallowed or their fumes are breathed in. ... Plastic casting resins are found in various plastic casting resin products.

  14. LLNL casting technology

    Science.gov (United States)

    Shapiro, A. B.; Comfort, W. J., III

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US competiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  15. Special thermite cast irons

    Directory of Open Access Journals (Sweden)

    Yu. Zhiguts

    2008-07-01

    Full Text Available The given paper deals with the problems of the synthesis of cast iron by metallothermy synthesis. On the basis of investigated method of calculations structures of charges have been arranged and cast iron has been synthesized further. Peculiarities metallothermic smelting were found, mechanical properties and structure of received cast iron were investigated and different technologies for cast iron receiving were worked out.

  16. Differential genetic and environmental influences on developmental trajectories of antisocial behavior from adolescence to young adulthood.

    Science.gov (United States)

    Zheng, Yao; Cleveland, H Harrington

    2015-12-01

    Little research has investigated differential genetic and environmental influences on different developmental trajectories of antisocial behavior. This study examined genetic and environmental influences on liabilities of being in life-course-persistent (LCP) and adolescent-limited (AL) type delinquent groups from adolescence to young adulthood while considering nonviolent and violent delinquency subtypes and gender differences. A genetically informative sample (n = 356, 15-16 years) from the first three waves of In-Home Interview of the National Longitudinal Study of Adolescent to Adult Health was used, with 94 monozygotic and 84 dizygotic pairs of same-sex twins (50% male). Biometric liability threshold models were fit and found that the male-specific LCP type class, chronic, showed more genetic influences, while the AL type classes, decliner and desister, showed more environmental influences. Genetic liability and shared environment both influence the persistence of antisocial behavior. The development of female antisocial behavior appears to be influenced more by shared environment.

  17. PHYSICAL SIMULATION OF CONTINUOUS ROLL CASTING PROCESS

    Institute of Scientific and Technical Information of China (English)

    L.H. Zhan; J. Zhong; X.Q. Li; M.H. Huang

    2005-01-01

    A series of simulating experimental studies on the rheological behavior and its influential factors of aluminum alloy in continuous roll-casting process have been explored in this paper with a Gleeble-1500 Thermal-Mechanical Simulation Tester and a set of special clamp system. Relevant rheological rules in the process of coupling transient solidification and continuous deformation of roll-casting conditions are obtained. Experimental results indicate that four different characteristic stages exist in the whole rheological process, and relative constitutive models suitable for the given conditions of continuous roll casting process have been established through multivariable linear regression analysis of the experimental data.

  18. Numerical Simulation of Stress and Deformation for a Duplex Stainless Steel Impeller during Casting and Heat Treatment Processes

    Institute of Scientific and Technical Information of China (English)

    Lugui CHEN; Yong LING; Xiuhong KANG; Lijun XIA; Dianzhong LI

    2008-01-01

    A large-scale, thin wall duplex stainless steel impeller with complex geometry was deformed severely and unpredictably during casting and heat treatment processes resulted in dimensional failure for the final part. In this paper, the distortion of the impeller during casting and heat treatment was calculated. A commercial software, Experto-ViewCast, was used to simulate the transient heat transfer, solidification and mechanical behaviors during the casting and the heat treatment process. The coupled set of governing differential equations for mass, energy and mechanical balance were solved by finite control volume and finite element method. A thermoelastic-visco-plastic rheological model was used to compute the constrained shrinkage of the casting. At each time increment, a coupling of the heat transfer and mechanics was performed. Comparison of the experimental measurements with the model predictions showed good agreement. From the calculated displacements of key points of the blade, the proper inverse displacements were determined to provide an optimum casting pattern and to achieve a uniform and reasonable machining allowance for both faces of the blade.

  19. Impurity behaviors in carbon allotropes observed by the time-differential perturbed angular correlation method

    International Nuclear Information System (INIS)

    The time-differential perturbed angular correlation (TDPAC) method is a nuclear spectroscopy that can provide information on the electromagnetic moments of probe nuclei and/or local fields in matter through hyperfine interactions between the probe and extranuclear fields. In this report are presented TDPAC studies on the dynamic behaviors and electronic states of the 140Ce probe introduced in carbon allotropes-fullerenes, graphite, and diamond. Apart from these works, we have developed a new probe 19F making use of a short-lived secondary beam of 19O for a wider application of this spectroscopy to materials science. The new online TDPAC method with the 19F (←19O) probe is also presented here. (author)

  20. Behavioral differentiation of mice exposed to a water tank social interaction test.

    Science.gov (United States)

    Nejdi, A; Guastavino, J M; Lalonde, R; Desor, D; Krafft, B

    1996-02-01

    Male or female C57BL/6J mice were exposed to a water tank in which food could be obtained only by wading in the water towards a feeder. Behavioral differentiation occurred in that three distinct categories could be distinguished: major carriers (transporting over 80% of the food pellets), sporadic carriers (transporting less than 20% of the food pellets) and non-carriers. In the elevated + -maze, major carriers were more willing to explore open spaces than non-carriers. Sporadic carriers showed some evidence of the same tendency of decreased anxiety, but in a minor way. The willingness of mice to become carriers is associated with their willingness to explore novel areas. This test may be useful for the assessment of anxiolytic compounds in a social situation.

  1. Structural, electronic, mechanical, and transport properties of phosphorene nanoribbons: Negative differential resistance behavior

    Science.gov (United States)

    Maity, Ajanta; Singh, Akansha; Sen, Prasenjit; Kibey, Aniruddha; Kshirsagar, Anjali; Kanhere, Dilip G.

    2016-08-01

    Structural, electronic, mechanical, and transport properties of two different types of phosphorene nanoribbons are calculated within the density functional theory and nonequilibrium Green's function formalisms. Armchair nanoribbons turn out to be semiconductors at all widths considered. Zigzag nanoribbons are metallic in their layer-terminated structure, but undergo Peierls-like transition at the edges. Armchair nanoribbons have smaller Young's modulus compared to a monolayer, while zigzag nanoribbons have larger Young's modulus. Edge reconstruction further increases the Young's modulus of zigzag nanoribbons. A two-terminal device made of zigzag nanoribbons show negative differential resistance behavior that is robust with respect to edge reconstruction. We have also calculated the I -V characteristics for two nonzero gate voltages. The results show that the zigzag nanoribbons display strong p -type character.

  2. Adolescent behavioral and neural reward sensitivity: a test of the differential susceptibility theory.

    Science.gov (United States)

    Richards, J S; Arias Vásquez, A; von Rhein, D; van der Meer, D; Franke, B; Hoekstra, P J; Heslenfeld, D J; Oosterlaan, J; Faraone, S V; Buitelaar, J K; Hartman, C A

    2016-01-01

    Little is known about the causes of individual differences in reward sensitivity. We investigated gene-environment interactions (GxE) on behavioral and neural measures of reward sensitivity, in light of the differential susceptibility theory. This theory states that individuals carrying plasticity gene variants will be more disadvantaged in negative, but more advantaged in positive environments. Reward responses were assessed during a monetary incentive delay task in 178 participants with and 265 without attention-deficit/hyperactivity disorder (ADHD), from N=261 families. We examined interactions between variants in candidate plasticity genes (DAT1, 5-HTT and DRD4) and social environments (maternal expressed emotion and peer affiliation). HTTLPR short allele carriers showed the least reward speeding when exposed to high positive peer affiliation, but the most when faced with low positive peer affiliation or low maternal warmth. DAT1 10-repeat homozygotes displayed similar GxE patterns toward maternal warmth on general task performance. At the neural level, DRD4 7-repeat carriers showed the least striatal activation during reward anticipation when exposed to high maternal warmth, but the most when exposed to low warmth. Findings were independent of ADHD severity. Our results partially confirm the differential susceptibility theory and indicate the importance of positive social environments in reward sensitivity and general task performance for persons with specific genotypes. PMID:27045841

  3. On the Large Time Behavior of the Solutions of a Nonlocal Ordinary Differential Equation with Mass Conservation

    Science.gov (United States)

    Hilhorst, Danielle; Matano, Hiroshi; Nguyen, Thanh Nam; Weber, Hendrik

    2016-09-01

    We consider an initial value problem for a nonlocal differential equation with a bistable nonlinearity in several space dimensions. The equation is an ordinary differential equation with respect to the time variable t, while the nonlocal term is expressed in terms of spatial integration. We discuss the large time behavior of solutions and prove, among other things, the convergence to steady-states. The proof that the solution orbits are relatively compact is based upon the rearrangement theory.

  4. Simultaneous Characterization for the Organic Additive Burnout of Aqueous Tape Casting Aluminum Nitride by Thermogravimetry-Differential Scanning Calorimetry-Mass Spectrometry%水基AlN流延膜有机添加剂排胶过程的热重-差示扫描热量-质谱研究

    Institute of Scientific and Technical Information of China (English)

    于惠梅; 雒晓军; 陆昌伟; 奚同庚; 罗澜

    2004-01-01

    In this work, through the comparison analysis with the results of the thermogravimetry-differential scanning calorimetry-mass spectrometry (TG-DSC-MS) coupling techniques for the three organic additive and aqueous tape casting aluminum nitride in air and nitrogen atmosphere, it can be found that the plasticity glycerol was almost burnout before 350℃ in two atmosphere; the binder PVA124 was almost burnout before 600℃ in air, there was little left in nitrogen; The mass losses of the dispersant DP270 in air and nitrogen atmosphere were about 73.32% and 65.51% before 600℃ ; The mass losses of the aqueous tape casting aluminum nitride in air (14.08%) were higher that in nitrogen (10.75%) before 600℃. It can be concluded that the organic additive burnout of the aqueous tape casting aluminum nitride in air atmosohere was better than in nitrogen atmosphere.

  5. Behavioral analysis of differential Hebbian learning in closed-loop systems

    DEFF Research Database (Denmark)

    Kulvicius, Tomas; Kolodziejski, Christoph; Tamosiunaite, Minija;

    2010-01-01

    Understanding closed loop behavioral systems is a non-trivial problem, especially when they change during learning. Descriptions of closed loop systems in terms of information theory date back to the 1950s, however, there have been only a few attempts which take into account learning, mostly meas...... measures and investigating their development during learning. This way we can show that within well-specified scenarios there are indeed agents which are optimal with respect to their structure and adaptive properties.......Understanding closed loop behavioral systems is a non-trivial problem, especially when they change during learning. Descriptions of closed loop systems in terms of information theory date back to the 1950s, however, there have been only a few attempts which take into account learning, mostly...... measuring information of inputs. In this study we analyze a specific type of closed loop system by looking at the input as well as the output space. For this, we investigate simulated agents that perform differential Hebbian learning (STDP). In the first part we show that analytical solutions can be found...

  6. Glovebox Advanced Casting System Casting Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses. Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.

  7. Fatigue Properties of Cast Magnesium Wheels

    Science.gov (United States)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-08-01

    This paper investigates the fatigue properties and deformation behavior of a newly developed Mg-2.96Nd-0.21Zn-0.39Zr magnesium alloy wheel in both as-cast and T6 conditions. Compared with the as-cast alloy, the T6-treated alloy shows a significant increase in fatigue strength and cyclic stress amplitude. This is believed to be attributed to the change of defect type from porosity to oxides and the increased matrix strength in the T6 (peak-aged) condition. For the as-cast alloy wheel, fatigue failure mainly originated from the cast defects including porosity, oxide film, and inclusion at or near the sample surface. In the T6-treated alloy, however, oxides and inclusions or slip bands initiate the fatigue cracks. Solution treatment appears to reduce or eliminate the shrinkage porosity because of grain growth and dissolution of as-cast eutectic phases in the grain boundaries. The cyclic stress amplitude of the as-cast alloy increases with increasing the number of cycles, while the T6-treated alloy shows cyclic softening after the stress reaches a maximum value. The Coffin-Manson law and Basquin equation can be used to evaluate the life of low cycle fatigue. The developed long crack model and multi-scale fatigue (MSF) models can be used to predict high-cycle fatigue life of the Mg-2.96Nd-0.21Zn-0.39Zr alloys with or without casting defects.

  8. Fatigue Properties of Cast Magnesium Wheels

    Science.gov (United States)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-05-01

    This paper investigates the fatigue properties and deformation behavior of a newly developed Mg-2.96Nd-0.21Zn-0.39Zr magnesium alloy wheel in both as-cast and T6 conditions. Compared with the as-cast alloy, the T6-treated alloy shows a significant increase in fatigue strength and cyclic stress amplitude. This is believed to be attributed to the change of defect type from porosity to oxides and the increased matrix strength in the T6 (peak-aged) condition. For the as-cast alloy wheel, fatigue failure mainly originated from the cast defects including porosity, oxide film, and inclusion at or near the sample surface. In the T6-treated alloy, however, oxides and inclusions or slip bands initiate the fatigue cracks. Solution treatment appears to reduce or eliminate the shrinkage porosity because of grain growth and dissolution of as-cast eutectic phases in the grain boundaries. The cyclic stress amplitude of the as-cast alloy increases with increasing the number of cycles, while the T6-treated alloy shows cyclic softening after the stress reaches a maximum value. The Coffin-Manson law and Basquin equation can be used to evaluate the life of low cycle fatigue. The developed long crack model and multi-scale fatigue (MSF) models can be used to predict high-cycle fatigue life of the Mg-2.96Nd-0.21Zn-0.39Zr alloys with or without casting defects.

  9. A fracture mechanics safety concept to assess the impact behavior of ductile cast iron containers for shipping and storage of radioactive materials

    International Nuclear Information System (INIS)

    Within the scope of the German licensing procedures for shipping and storage containers for radioactive materials made of ductile cast iron, BAM performs approval design tests including material tests to ensure the main safety goals of shielding, leaktightness and subcriticality under ''Type B accident conditions''. So far the safety assessment concept of BAM is based essentially on the experimental proof of container strength by prototype testing under most damaging test conditions in connection with complete approval design tests, and has been developed especially for cylindrical casks like CASTOR- and TN-design. In connection with the development of new container constructions such as ''cubic cast containers'', and the fast developments in the area of numerical calculation methods, there is a need for a more flexible safety concept especially considering fracture mechanics aspects.This paper presents the state of work at BAM for such an extended safety concept for ductile cast iron containers, based on a detailed brittle fracture safe design proof. The requirements on stress analysis (experimental or numerical), material properties, material qualification, quality assurance provisions and fracture mechanics safety assessment, including well defined and justified factors of safety, are described. ((orig.))

  10. Expandable pattern casting research

    Science.gov (United States)

    1993-09-01

    The Expandable Pattern Casting (EPC) Process is a developing foundry technology that allows designers the opportunity to consolidate parts, reduce machining, and minimize assembly operations. An air gauging system was developed for measuring foam patterns; exact shrinkage depended on type and density of the foam. Compaction studies showed that maximum sand densities in cavities and under overhangs are achieved with vibrational amplitudes 0.001-0.004 in., and that sand moved most freely within a few inches of the top free surface. Key to complete mold filling while minimizing casting defects lies in removing the foam decomposition products. The most precise iron castings were made by EPC in four commercial EPC foundries, with attention paid to molding and compaction. EP cast 60-45-12 ductile iron had yield strengths, ultimate strengths, and elastic modulus similar to conventionally cast ductile iron cast from the same ladle.

  11. High integrity automotive castings

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D. [Eck Industries Inc., St. Manitowoc, WI (United States)

    2007-07-01

    This paper described the High Integrity Magnesium Automotive Casting (HI-MAC) program, which was developed to ensure the widespread adoption of magnesium in structural castings. The program will encourage the use of low pressure permanent molds, squeeze casting, and electromagnetic pumping of magnesium into dies. The HI-MAC program is currently investigating new heat treatment methods, and is in the process of creating improved fluid flow and solidification modelling to produce high volume automotive components. In order to address key technology barriers, the program has been divided into 8 tasks: (1) squeeze casting process development; (2) low pressure casting technology; (3) thermal treatment; (4) microstructure control; (5) computer modelling and properties; (6) controlled molten metal transfer and filling; (7) emerging casting technologies; and (8) technology transfer throughout the automotive value chain. Technical challenges were outlined for each of the tasks. 1 ref., 3 tabs., 5 figs.

  12. Caste and power

    DEFF Research Database (Denmark)

    Roy, Dayabati

    2011-01-01

    This paper explores the institution of caste and its operation in a micro-level village setting of West Bengal, an Indian state, where state politics at grass roots level is vibrant with functioning local self-government and entrenched political parties. This ethnographic study reveals that caste......–ideological field, the concept of caste-hierarchy seems to continue as an influencing factor, even in the operation of leftist politics....

  13. Sc对金属型铸造甜一Si—Cu.Mg合金疲劳行为的影响%Influence of Sc on fatigue behavior of permanent-mould casting AI-Si-Cu-Mg alloy

    Institute of Scientific and Technical Information of China (English)

    车欣; 陈立佳; 李锋

    2012-01-01

    In order to determine the effect of rare earth element Sc on the low-cycle fatigue behavior of the permanent-mould casting Al-Si-Cu-Mg alloy,the low-cycle fatigue tests were performed for the permanent-mould casting Al-Si-Cu-Mg alloys with and without adding Sc.The results show that at the higher total strain amplitudes,both permanent-mould casting Al-Si-Cu-Mg and Al-Si-Cu-Mg-Sc alloys exhibit the cyclic strain hardening.However,the rare earth element Sc has greater influence on the cyclic stress response behavior of the alloy at the low total strain amplitude.For the Al-Si-Cu-Mg alloy,the cyclic strain hardening occurs at the initial stage of fatigue deformation,and the cyclic stability is noted at the later stage of fatigue deformation.However,the cyclic strain hardening is observed during the whole fatigue deformation for the Al-Si-Cu-Mg-Sc alloy.Furthermore,the addition of rare earth element Sc can effectively enhance the cyclic deformation resistance and prolong the fatigue lives of the permanent-mould casting Al-Si-Cu-Mg alloy.%为了确定稀土元素Sc对金属型铸造Al-Si-Cu-Mg合金低周疲劳行为的影响规律,针对含Sc和不含Sc的金属型铸造Al-Si-Cu-Mg合金的低周疲劳行为进行了对比研究.结果表明,当外加总应变幅较高时,金属型铸造Al-Si-Cu-Mg合金和Al-Si-Cu-Mg-Sc合金均呈现循环应变硬化现象,而在低的外加总应变幅下,稀土元素Sc对合金的循环应力响应行为产生较大影响,其中Al-Si-Cu-Mg合金在疲劳变形初期表现为循环应变硬化,在疲劳变形后期则表现为循环稳定,而Al-Si-Cu-Mg-Sc合金在整个疲劳变形期间均发生循环应变硬化.此外,稀土元素Sc的加入可以有效提高金属型铸造Al-Si-Cu-Mg合金的循环变形抗力和低周疲劳寿命.

  14. Us and me : team identification and individual differentiation as complementary drivers of team members' citizenship and creative behaviors

    NARCIS (Netherlands)

    Janssen, O.; Huang, X

    2008-01-01

    The authors investigate team identification and individual differentiation as complementary drivers of team members' citizenship and creative behavior. As hypothesized, the results of a survey among 157 middle-management team members show team identification to be positively related to citizenship b

  15. Clinical Utility of Short Social Cognitive Tests in Early Differentiation of Behavioral Variant Frontotemporal Dementia from Alzheimer’s Disease

    DEFF Research Database (Denmark)

    Buhl, Christian; Stokholm, Jette; Gade, Anders

    2013-01-01

    Traditional cognitive tests used in clinical practice may not be sensitive enough for the early differentiation of behavioral variant frontotemporal dementia (bvFTD) from Alzheimer's disease (AD). A growing body of literature has shown that deficits in various aspects of social cognition can be f...

  16. Manipulating Migration Behavior of Magnetic Graphene Oxide via Magnetic Field Induced Casting and Phase Separation toward High-Performance Hybrid Ultrafiltration Membranes.

    Science.gov (United States)

    Xu, Zhiwei; Wu, Tengfei; Shi, Jie; Wang, Wei; Teng, Kunyue; Qian, Xiaoming; Shan, Mingjing; Deng, Hui; Tian, Xu; Li, Cuiyu; Li, Fengyan

    2016-07-20

    Hybrid membranes blended with nanomaterials such as graphene oxide (GO) have great opportunities in water applications due to their multiple functionalities, but they suffer from low modification efficiency of nanomaterials due to the fact that plenty of the nanomaterials are embedded within the polymer matrix during the blending process. Herein, a novel Fe3O4/GO-poly(vinylidene fluoride) (Fe3O4/GO-PVDF) hybrid ultrafiltration membrane was developed via the combination of magnetic field induced casting and a phase inversion technique, during which the Fe3O4/GO nanocomposites could migrate toward the membrane top surface due to magnetic attraction and thereby render the surface highly hydrophilic with robust resistance to fouling. The blended Fe3O4/GO nanocomposites migrated to the membrane surface with the magnetic field induced casting, as verified by X-ray photoelectron spectroscopy, elemental analysis, and energy dispersive X-ray spectroscopy. As a result, the novel membranes exhibited significantly improved hydrophilicity (with a contact angle of 55.0°) and water flux (up to 595.39 L m(-2) h(-1)), which were improved by 26% and 206%, 12% and 49%, 25% and 154%, and 11% and 33% compared with those of pristine PVDF membranes and PVDF hybrid membranes blended with GO, Fe3O4, and Fe3O4/GO without the assistance of magnetic field during membrane casting, respectively. Besides, the novel membranes showed high rejection of bovine serum albumin (>92%) and high flux recovery ratio (up to 86.4%). Therefore, this study presents a novel strategy for developing high-performance hybrid membranes via manipulating the migration of nanomaterials to the membrane surface rather than embedding them in the membrane matrix. PMID:27355273

  17. Cast iron - a predictable material

    OpenAIRE

    Jorg C. Sturm; Guido Busch

    2011-01-01

    High strength compacted graphite iron (CGI) or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process s...

  18. Comparative analysis of expressed sequence tags from three castes and two life stages of the termite Reticulitermes flavipes

    Directory of Open Access Journals (Sweden)

    Steller Matthew M

    2010-08-01

    Full Text Available Abstract Background Termites (Isoptera are eusocial insects whose colonies consist of morphologically and behaviorally specialized castes of sterile workers and soldiers, and reproductive alates. Previous studies on eusocial insects have indicated that caste differentiation and behavior are underlain by differential gene expression. Although much is known about gene expression in the honey bee, Apis mellifera, termites remain relatively understudied in this regard. Therefore, our objective was to assemble an expressed sequence tag (EST data base for the eastern subterranean termite, Reticulitermes flavipes, for future gene expression studies. Results Soldier, worker, and alate caste and two larval cDNA libraries were constructed, and approximately 15,000 randomly chosen clones were sequenced to compile an EST data base. Putative gene functions were assigned based on a BLASTX Swissprot search. Categorical in silico expression patterns for each library were compared using the R-statistic. A significant proportion of the ESTs of each caste and life stages had no significant similarity to those in existing data bases. All cDNA libraries, including those of non-reproductive worker and soldier castes, contained sequences with putative reproductive functions. Genes that showed a potential expression bias among castes included a putative antibacterial humoral response and translation elongation protein in soldiers and a chemosensory protein in alates. Conclusions We have expanded upon the available sequences for R. flavipes and utilized an in silico method to compare gene expression in different castes of an eusocial insect. The in silico analysis allowed us to identify several genes which may be differentially expressed and involved in caste differences. These include a gene overrepresented in the alate cDNA library with a predicted function of neurotransmitter secretion or cholesterol absorption and a gene predicted to be involved in protein

  19. Expendable Pattern Casting Technology

    Science.gov (United States)

    1990-07-01

    The expendable pattern casting (EPC) process is a potential casting process breakthrough which could dramatically improve the competitiveness of the U.S. foundry industry. Cooperatively supported by U.S. Industry and the Department of Energy and managed by the American Foundrymen's Society, a project was started in May 1989 to develop and optimize expendable pattern casting technology. Four major tasks were conducted in the first phase of the project. Those tasks involved: (1) reviewing published literature to determine the major problems in the EPC process; (2) evaluating factors influencing sand flow and compaction; (3) evaluating and comparing casting precision obtained in the EPC process with that obtained in other processes; and (4) identifying critical parameters that control dimensional precision and defect formation in EP castings.

  20. Multi-layers castings

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2010-01-01

    Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

  1. Static and cyclic pullout behavior of cast-in-place headed and bonded anchors with large embedment depths in cracked concrete

    Energy Technology Data Exchange (ETDEWEB)

    Delhomme, F., E-mail: fabien.delhomme@insa-lyon.fr [University of Lyon, INSA-Lyon, LGCIE, F-69621 Villeurbanne (France); Roure, T.; Arrieta, B. [EDF SEPTEN Compagny, Civil Engineering, Villeurbanne (France); Limam, A. [University of Lyon, INSA-Lyon, LGCIE, F-69621 Villeurbanne (France)

    2015-06-15

    Highlights: • Optimizing the design and identifying margin of the headed fasteners used in French nuclear power plants. • Static and cyclic pullout tests on cast in place anchorage composed of an anchor plate welded to four headed or bonded rods. • Experimental data base on tests on anchor plates. • Anchor with large embedment depths in cracked concrete. • Edge effects. - Abstract: The equipment of French nuclear power plants is fixed on reinforced concrete structures with base plate with headed fasteners. EDF decided to carry out an experimental research program in partnership with LGCIE in order to optimize the design of the headed fasteners and identify margin. This article introduces the results of pullout tests on anchors with large embedment cast in place in a reinforced concrete block. The anchorage are composed of an anchor plate welded to four ribbed bars or headed smooth studs. The studied parameters are: the type of loading (static or cyclic), the edge distance, the state of cracking of the concrete block. The anchors with headed rods or ribbed bars have a steel rod failure mode in agreement with their initial design. However, an optimization of the size on the headed anchors seems to be expected in order to improve their installation. This experimental campaign will provide a data base enabling the development of numerical models in order to improve the design.

  2. Static and cyclic pullout behavior of cast-in-place headed and bonded anchors with large embedment depths in cracked concrete

    International Nuclear Information System (INIS)

    Highlights: • Optimizing the design and identifying margin of the headed fasteners used in French nuclear power plants. • Static and cyclic pullout tests on cast in place anchorage composed of an anchor plate welded to four headed or bonded rods. • Experimental data base on tests on anchor plates. • Anchor with large embedment depths in cracked concrete. • Edge effects. - Abstract: The equipment of French nuclear power plants is fixed on reinforced concrete structures with base plate with headed fasteners. EDF decided to carry out an experimental research program in partnership with LGCIE in order to optimize the design of the headed fasteners and identify margin. This article introduces the results of pullout tests on anchors with large embedment cast in place in a reinforced concrete block. The anchorage are composed of an anchor plate welded to four ribbed bars or headed smooth studs. The studied parameters are: the type of loading (static or cyclic), the edge distance, the state of cracking of the concrete block. The anchors with headed rods or ribbed bars have a steel rod failure mode in agreement with their initial design. However, an optimization of the size on the headed anchors seems to be expected in order to improve their installation. This experimental campaign will provide a data base enabling the development of numerical models in order to improve the design

  3. Effect of zirconium addition on the grain size and mechanical behavior of aluminum grain refined by titanium plus boron (Ti+B) in the as cast and cold extruded conditions

    International Nuclear Information System (INIS)

    Aluminum and its alloys are the second most commonly used metal for a variety of industrial applications. They normally solidify in coarse grain columnar structure which tends to reduce their mechanical behavior and surface quality. It was found that this large grain size structure can be refined by using titanium, Ti, or titanium plus boron, Ti+B, and using the latter resulted in reducing the amount of Ti to fifth its values although boron itself is not a grain refiner. This is why it is becoming customary in the aluminum foundry to add Ti or Ti+B to their melt before solidification. The available literature reveals that most of the work is directed towards the metallurgical aspects and little was directed on the mechanical aspects. To the best of the authors knowledge, no work was directed on the aspects of grain refiners on the formability of metals. In this paper, the effect of addition of Zr on the mechanical properties of commercially pure aluminum grain refined by Ti+B in the as cast and extruded conditions is investigated. Comparison between the addition of Zr alone or Zr+Ti+B is also investigated. It was found that addition of Ti+B either alone or in the presence of Zr resulted in grain refinement of aluminum both in the as cast and in the cold extruded conditions. The maximum reduction in grain size was 53.22% and 76.92%, respectively. Similarly, it was found that addition of Ti+B either alone or in the presence of Zr to Al resulted in improvement of its Vickers's hardness, However addition of Zr alone to Al resulted in decrease of its hardness in the as cast conditions but increase in the extruded condition .The maximum increase was in the case of adding both of them in the extruded condition being 94.59 %, (from Hv 37 to Hv72). Similarly the ultimate tensile strength, UTS, was improved at all additions except when Ti+B or Zr is added alone. On the whole it may be concluded that addition of Zr to Al grain refined by Ti+B resulted in enhancement of its

  4. Microdefects in cast multicrystalline silicon

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, E.; Klinger, D.; Bergmann, S. [Inst. of Crystal Growth Berlin (Germany)

    1995-08-01

    The microdefect etching behavior of cast multicrystalline BAYSIX and SILSO samples is mainly the same as that of EFG silicon, in spite of the very different growth parameters applied to these two techniques and the different carbon contents of the investigated materials. Intentional decorating of mc silicon with copper, iron and gold did not influence the results of etching and with help of infrared transmission microscopy no metal precipitates at the assumed microdefects could be established. There are many open questions concerning the origin of the assumed, not yet doubtless proved microdefects.

  5. Two insular regions are differentially involved in behavioral variant FTD and nonfluent/agrammatic variant PPA.

    Science.gov (United States)

    Mandelli, Maria Luisa; Vitali, Paolo; Santos, Miguel; Henry, Maya; Gola, Kelly; Rosenberg, Lynne; Dronkers, Nina; Miller, Bruce; Seeley, William W; Gorno-Tempini, Maria Luisa

    2016-01-01

    The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) and the behavioral variant frontotemporal dementia (bvFTD) are focal neurodegenerative disorders belonging to the FTD-spectrum clinical syndromes. NfvPPA is characterized by effortful speech and/or agrammatism and left frontal atrophy, while bvFTD is characterized by social-emotional dysfunction often accompanied by right-lateralized frontal damage. Despite their contrasting clinical presentations, both disorders show prominent left anterior insula atrophy. We investigated differential patterns of insular sub-region atrophy in nfvPPA and bvFTD. Based on knowledge of insular connectivity and physiology, we hypothesized that the left superior precentral region of the dorsal anterior insula (SPGI) would be more atrophic in nvfPPA due to its critical role in motor speech, whereas the ventral anterior region would be more atrophied in bvFTD reflecting its known role in social-emotional-autonomic functions. Early stage nfvPPA and bvFTD patients matched for disease severity, age, gender and education and healthy controls participated in the study. Detailed clinical history, neurological examination, neuropsychological screening evaluation, and high-resolution T1-weighted brain magnetic resonance imaging (MRI) were collected. Voxel-based morphometry (VBM) was applied to perform group comparisons across the whole brain and in bilateral insula region of interest (ROI). Correlation analyses between insular sub-region atrophy and relevant clinical features were performed. Whole brain group comparisons between nfvPPA and bvFTD showed the expected predominantly left or right anterior insular atrophy pattern. ROI analysis of bilateral insula showed that the left SPGI was significantly more atrophied in nfvPPA compared to bvFTD, while the bilateral ventral anterior and right dorsal anterior insula sub-regions were more atrophied in bvFTD than nfvPPA. Only left SPGI volume correlated with speech production

  6. Two insular regions are differentially involved in behavioral variant FTD and nonfluent/agrammatic variant PPA.

    Science.gov (United States)

    Mandelli, Maria Luisa; Vitali, Paolo; Santos, Miguel; Henry, Maya; Gola, Kelly; Rosenberg, Lynne; Dronkers, Nina; Miller, Bruce; Seeley, William W; Gorno-Tempini, Maria Luisa

    2016-01-01

    The non-fluent/agrammatic variant of primary progressive aphasia (nfvPPA) and the behavioral variant frontotemporal dementia (bvFTD) are focal neurodegenerative disorders belonging to the FTD-spectrum clinical syndromes. NfvPPA is characterized by effortful speech and/or agrammatism and left frontal atrophy, while bvFTD is characterized by social-emotional dysfunction often accompanied by right-lateralized frontal damage. Despite their contrasting clinical presentations, both disorders show prominent left anterior insula atrophy. We investigated differential patterns of insular sub-region atrophy in nfvPPA and bvFTD. Based on knowledge of insular connectivity and physiology, we hypothesized that the left superior precentral region of the dorsal anterior insula (SPGI) would be more atrophic in nvfPPA due to its critical role in motor speech, whereas the ventral anterior region would be more atrophied in bvFTD reflecting its known role in social-emotional-autonomic functions. Early stage nfvPPA and bvFTD patients matched for disease severity, age, gender and education and healthy controls participated in the study. Detailed clinical history, neurological examination, neuropsychological screening evaluation, and high-resolution T1-weighted brain magnetic resonance imaging (MRI) were collected. Voxel-based morphometry (VBM) was applied to perform group comparisons across the whole brain and in bilateral insula region of interest (ROI). Correlation analyses between insular sub-region atrophy and relevant clinical features were performed. Whole brain group comparisons between nfvPPA and bvFTD showed the expected predominantly left or right anterior insular atrophy pattern. ROI analysis of bilateral insula showed that the left SPGI was significantly more atrophied in nfvPPA compared to bvFTD, while the bilateral ventral anterior and right dorsal anterior insula sub-regions were more atrophied in bvFTD than nfvPPA. Only left SPGI volume correlated with speech production

  7. The ancient Chinese casting techniques

    Directory of Open Access Journals (Sweden)

    Tan Derui

    2011-02-01

    Full Text Available In the course of Chinese civilization, which lasted more than 5,000 years, casting production has made a huge contribution. In this paper, some representative metal castings were presented. According to their forming techniques, they can be grouped into stone mould casting, clay mould casting, ablation casting, lost wax casting, stack casting, permanent mould casting, sand casting, etc. According to their materials, they can be categorized into tin bronze, bimetallic bronze, malleable cast iron, ductile cast iron, brass, cupronickel alloy (Packtong, etc. According to their surface decorative techniques they can be devided into gem inlay, gilding, gold and silver inlay, copper inlay, engraved decoration, surface tin-enrichment, mother-of-pearl inlay, burnished works with gold or silver inlay, surface coloring and cloisonné enamel, etc.

  8. Microstructure, thermal behavior and mechanical properties of squeeze cast SiC, ZrO2 or C reinforced ZA27 composites

    International Nuclear Information System (INIS)

    Research highlights: → ZA27 with 5% SiC, ZrO2 or C particles are synthesized by stirring then squeezed. → Particles refine the structure. 50 MPa decreases porosity% and increases density. → α and β nucleation temperatures of the composites are lower than those of the matrix. → Particles accelerate age hardening and increase peak hardness of the composites → Particles reduce the CTEs of composites compared to those of the matrix. - Abstract: ZA27 alloy based composites were synthesized by stirring method, followed by squeeze casting. Stir casting was employed successfully to incorporate 5 vol.% of various reinforcement particulates, namely, SiC, ZrO2 or C. The porosity in the composites was decreased by squeeze pressure. The presence of particles and/or application of squeeze pressure during solidification resulted in considerable refinement in the structure of the composites. The microstructures, X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDXA) results indicated that no significant reactions occurred at the interface between the SiC or C particles and ZA27 alloy. However, in case of ZrO2 reinforced ZA27, the ZrO2 reacted with Cu present in the molten ZA27 alloy, forming Cu5Zr. Thermal analysis showed that both α and β nucleation and growth temperatures of the composites were lower than those of the ZA27 alloy. The presence of particles in the as-cast or squeezed composites led to not only an accelerated age hardening response, but also an increase in the peak hardness of the composites. The values of coefficient of thermal expansion (CTE) of the composites were drastically lower as compared to those of the ZA27 alloy. The tensile properties of the composites decreased as a result of the addition of the particles. Scanning electron microscope (SEM) pictures of the composites indicated that cracks mainly initiated at particle-matrix interface, propagated through the matrix and linked up with other cracks leading to failure of the

  9. Clean Metal Casting

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

  10. Controllable low-bias negative differential resistance, switching, and rectifying behaviors of dipyrimidinyl–diphenyl induced by contact mode

    International Nuclear Information System (INIS)

    The negative differential resistance (NDR) and the rectifying behaviors of a molecular device induced by a saturated hydrogen atom and contact modes are investigated. Results reveal low-bias NDR behaviors of dipyrimidinyl–diphenyl (DD) molecule without saturated H atoms. NDR behavior can be eliminated depending on the contact sites. However, the rectifying behaviors of DD-molecule with saturated H atoms are apparent for all considered contact modes. In addition, the possible contact mode of the molecule in the experiment [12] was identified by examining the effect of molecular adsorption sites on gold electrodes and saturated hydrogen atom on conductance. The mechanism underlying various properties are analyzed with the highest occupied molecular orbital, lowest unoccupied molecular orbital, and transmission spectra

  11. Compared production behavior of borax and unborax premixed SiC reinforcement Al7Si-Mg-TiB alloys composites with semi-solid stir casting method

    Science.gov (United States)

    Haryono, M. B.; Sulardjaka, Nugroho, Sri

    2016-04-01

    The present study was aimed to investigate the effect of borax additive on physical and mechanical properties of Al7Si-Mg-TiB with the reinforcement of silicon carbide. In this case, the different weight percentage from the reinforcement of SiC (10, 15, and 20% wt), and the borax additive (ratio 1:4) were homogenously added into the matrix by employing the semi-solid stir casting method at the temperature of 590°C. Al7Si-Mg-TiB melted in an electric resistance furnace at 800°C for 25 minutes and the holding time of 5 minutes; SiC was stirred with borax inside the chamber and heated at the temperature of 250°C for 25 minutes. Then, it melted by lowing the temperature into 590°C. The SiC-borax mixture was added into the electric resistance furnace, and automatically stirred by the stirrer at a constant speed (500 rpm for 3 minutes) in the composite A17Si-Mg-TiB. It melted when heated at 750°C for 17minutes,then, casting was performed on the prepared mould. The characterizations of Al7Si-Mg-TiB-SiC/borax were porosity, hardness, and microstructure on the Al7Si-Mg-TiB-SiC/ borax. The porosity of AMC tended to increase along with the increaseof the wt% SiC (1.4%-3.6%); however, borax additive underwent a decrease in porosity (0.14%-1.3%). Further, hardness tended to improve along with the increase of wt% SiC. The unboraxmixture had 79,6 HRB up to 94 HRB. Whereas, the borax additive mixture had 105,8 HRB up to 121 HRB.

  12. Symptomatic stent cast.

    LENUS (Irish Health Repository)

    Keohane, John

    2012-02-03

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  13. Symptomatic stent cast.

    Science.gov (United States)

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

    2008-02-01

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  14. CENTRIFUGAL CASTING MACHINE

    Science.gov (United States)

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  15. ASYMPTOTIC BEHAVIOR FOR NONOSCILLATORY SOLUTIONS OFREACTION-DIFFUSION DIFFERENTIAL EQUATIONS WITH SEVERAL DELAYS IN THE NEUTRAL TERM

    Institute of Scientific and Technical Information of China (English)

    徐美荣; 时宝

    2004-01-01

    In this paper, we first consider differential equations with several delays inthe neutral term of the form d/dt[y(t)+∑j=1L piy(t-ki)-∑j=1Mrjy(t-Pj)]+q(t)y(t-r)=0 for t∈R+,(1*) study various cases of coefficients in the neutral term and obtain the asymptotic behavior for nonoscillatory solution of (1") under some hypotheses. Moreover,we consider reaction-diffusion differential equations with several delays in the neutral term of the form α/αt[u(t,x)+∑i=1L piu(t-ki,x)-∑j=1M rju(t-Pj,x)]+q(t,x)u(t-r,x)=a2△u(t,x)for (t,x)∈R+ ×Ω. We also study various cases of coefficients in the neutral term and obtain the asymptotic behavior for nonoscillatory solutionun of (2*)under some hypotheses.

  16. Evolution of Social Insect Polyphenism Facilitated by the Sex Differentiation Cascade.

    Science.gov (United States)

    Klein, Antonia; Schultner, Eva; Lowak, Helena; Schrader, Lukas; Heinze, Jürgen; Holman, Luke; Oettler, Jan

    2016-03-01

    The major transition to eusociality required the evolution of a switch to canalize development into either a reproductive or a helper, the nature of which is currently unknown. Following predictions from the 'theory of facilitated variation', we identify sex differentiation pathways as promising candidates because of their pre-adaptation to regulating development of complex phenotypes. We show that conserved core genes, including the juvenile hormone-sensitive master sex differentiation gene doublesex (dsx) and a krüppel homolog 2 (kr-h2) with putative regulatory function, exhibit both sex and morph-specific expression across life stages in the ant Cardiocondyla obscurior. We hypothesize that genes in the sex differentiation cascade evolved perception of alternative input signals for caste differentiation (i.e. environmental or genetic cues), and that their inherent switch-like and epistatic behavior facilitated signal transfer to downstream targets, thus allowing them to control differential development into morphological castes.

  17. Combining noncontingent reinforcement and differential reinforcement schedules as treatment for aberrant behavior.

    OpenAIRE

    Marcus, B A; Vollmer, T R

    1996-01-01

    Research has shown that noncontingent reinforcement (NCR) can be an effective behavior-reduction procedure when based on a functional analysis. The effects of NCR may be a result of elimination of the contingency between aberrant behavior and reinforcing consequences (extinction) or frequent and free access to reinforcers that may reduce the participant's motivation to engage in aberrant behaviors or mands. If motivation is momentarily reduced, behavior such as mands may not be sensitive to p...

  18. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2011-01-01

    White Cast Iron (Ⅰ) White cast iron or ‘white iron' refers to the type of cast iron in which all of the carbon exists as carbide;there is no graphite in the as-cast structure and the fractured surface shows a white colour.White cast iron can be divided in three classes:· Normal white cast iron — this iron contains only C,Si,Mn,P and S,with no other alloying elements.· Low-alloy white cast iron — the total mass fraction of alloying elements is less than 5%.

  19. Differential Parenting and Children's Behavioral Problems: Curvilinear Associations and Mother-Father Combined Effects

    Science.gov (United States)

    Meunier, Jean Christophe; Bisceglia, Rossana; Jenkins, Jennifer M.

    2012-01-01

    In this study the associations between mothers' and fathers' differential parenting and children's oppositional and emotional problems were examined. A curvilinear relationship between differential parenting and children's outcomes was hypothesized, as well as the combined effect of mothers' and fathers' parenting. Data came from a community…

  20. Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

    Directory of Open Access Journals (Sweden)

    Todor Ivanov

    2011-02-01

    Full Text Available Within the project Functional Surfaces via Micro- and Nanoscaled Structures?which is part of the Cluster of Excellence 揑ntegrative Production Technology?established and financed by the German Research Foundation (DFG, an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1 μm on near-net-shape-casting parts has been developed. The common way to realize functional microstructures on metallic surfaces is to use laser ablation, electro discharge machining or micro milling. The handicap of these processes is their limited productivity. The approach of this project to raise the efficiency is to use the investment casting process to replicate microstructured surfaces by moulding from a laser-microstructured grand master pattern. The main research objective deals with the investigation of the single process steps of the investment casting process with regard to the moulding accuracy. Actual results concerning making of the wax pattern, suitability of ceramic mould and core materials for casting of an AlSi7Mg0.3 alloy as well as the knock-out behavior of the shells are presented. By using of the example of an intake manifold of a gasoline race car engine, a technical shark skin surface has been realized to reduce the drag of the intake air. The intake manifold consists of an air-restrictor with a defined inner diameter which is microstructured with technical shark skin riblets. For this reason the inner diameter cannot be drilled after casting and demands a very high accuracy of the casting part. A technology for the fabrication and demoulding of accurate microstructured castings are shown. Shrinkage factors of different moulding steps of the macroscopic casting part as well as the microscopic riblet structure have been examined as well.

  1. (Continuous casting 1985)

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, R.A.

    1985-06-12

    The report covers the Continuous Casting '85 Conference including informal discussions with conference attendees. In general, the papers presented at the conference concerned an overview of continuous steel casting worldwide, state-of-the-art aspects of steel continuous casting technology including caster startup problems, modifications, control system strategies, energy use profiles, quality control aspects, steel chemistry control, refractories, operational aspects of continuous casters, etc. No papers were presented in the development of thin section or thin strip casting of steel. Informal discussions were held with several conference attendees including (1) Bernard Trentini, Executive Director of the Association Technique De La Siderurgie Francaise in Paris, France (similar to the American Iron and Steel Institute); (2) Dr. Wolfgang Reichelt and Dr. Peter Voss-Spilker both of Mannesmann Demag Huttentechnik -a continuous casting and other steel making machine builder in-lieu of meeting at their plant in Duisburg, FRG on May 31; (3) Ewan C. Hewitt of Devote McKee Corp., Sheffield, England; (4) Wilfried Heinemann, head of R D Dept. at Concast Standard AG in Zurich, Switzerland; and (5) Hideo Ueno, engineer of melting section, Mitsubishi Steel Mfg. Co. Ltd, Tokyo Japan. A visit was made to the Teesside Laboratories of British Steel Corp. for discussions of their thin section casting research program in particular and R D program in general.

  2. Skeleton castings dynamic load resistance

    OpenAIRE

    M. Cholewa; J. Szajnar; T. Szuter

    2013-01-01

    Purpose: The article is to show selected results of research in a field of new type of cast spatial composite reinforcements. This article shows skeleton casting case as a particular approach to continuous, spatial composite reinforcement.Design/methodology/approach: The research is concerning properties of cast spatial microlattice structures called skeleton castings. In this paper results of impact test of skeleton casting with octahedron elementary cell were shown. The selection of interna...

  3. Comprehensive study of the abrasive wear and slurry erosion behavior of an expanded system of high chromium cast iron and microstructural modification for enhanced wear resistance

    Science.gov (United States)

    Chung, Reinaldo Javier

    High chromium cast irons (HCCIs) have been demonstrated to be an effective material for a wide range of applications in aggressive environments, where resistances to abrasion, erosion and erosion-corrosion are required. For instance, machinery and facilities used in mining and extraction in Alberta's oil sands suffer from erosion and erosion-corrosion caused by silica-containing slurries, which create challenges for the reliability and maintenance of slurry pumping systems as well as other processing and handling equipment. Considerable efforts have been made to determine and understand the relationship between microstructural features of the HCCIs and their wear performance, in order to guide the material selection and development for specific service conditions with optimal performance. The focus was previously put on a narrow group of compositions dictated by ASTM A532. However, with recent advances in casting technology, the HCCI compositional range can be significantly expanded, which potentially brings new alloys that can be superior to those which are currently employed. This work consists of three main aspects of study. The first one is the investigation of an expanded system of white irons with their composition ranging from 1 to 6 wt.% C and 5 to 45 wt.% Cr, covering 53 alloys. This work has generated wear and corrosion maps and established correlation between the performance and microstructural features for the alloys. The work was conducted in collaboration with the Materials Development Center of Weir Minerals in Australia, and the results have been collected in a database that is used by the company to guide materials selection for slurry pump components in Alberta oil sands and in other mining operations throughout the world. The second part consists of three case studies on effects of high chromium and high carbon, respectively, on the performance of the HCCIs. The third aspect is the development of an approach to enhance the wear resistance of

  4. Rheology of composite solid propellants during motor casting

    Science.gov (United States)

    Rogers, C. J.; Smith, P. L.; Klager, K.

    1978-01-01

    In a study conducted to evaluate flow parameters of uncured solid composite propellants during motor casting, two motors (1.8M-lb grain wt) were cast with a PBAN propellant exhibiting good flow characteristics in a 260-in. dia solid rocket motor. Attention is given to the effects of propellant compositional and processing variables on apparent viscosity as they pertain to rheological behavior and grain defect formation during casting. It is noted that optimized flow behavior is impaired with solid propellant loading. Non-Newtonian pseudoplastic flow is observed, which is dependent upon applied shear stress and the age of the uncured propellant.

  5. Behavior of Zr-Rich Phase in a Cast NiAl-33.5Cr-0.5ZrAlloy during Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There are many Zr particles in as-cast NiAl-33.5Cr-0.5Zr (at. pct) alloy, which usually exist at the edge of eutectic ofβ-NiAl and α-Cr. After air and furnace cooling solution treatments,for 1400℃, 2 h and 1450℃, 1 h, pure Zr phase remains in the furnace cooling (F.C.) state alloys and Ni2AlZr phase forms in the air cooling (A.C.) state alloys. During solution treatment at 1450℃, bulk and "fish bone" shape Zr-rich phases form respectively in F.C. and A.C. state alloys. A 'river' shape Ni2AlZr phase forms after 1450℃ for 1h F.C. and 850℃ for 12 h, F.C..The alloy has less pure Zr and Ni2AlZr phase after 1400℃ with both air and furnace cooling followed by 850℃ and 950℃ for 112 h, F.C. aging treatments, respectively. Additionally, there is a ternary eutectic of NiAlZr and a phase enriched Zr and Cr forms at the edge of the eutectic ofβ-NiAl and c-Cr in the alloy treated at 1400℃, 2 h, F.C. and 950℃, 12 h, F.C.

  6. Effect of Heat Treatments on the Microstructure, Hardness and Corrosion Behavior of Nondendritic AlSi9Cu3(Fe Cast Alloy

    Directory of Open Access Journals (Sweden)

    Nacer ZAZI

    2013-09-01

    Full Text Available In this paper we studied the influence of heat treatments on properties of AlSi9Cu3(Fe nondendritic cast alloy. Solution heat treatment, six hours at 520 °C, while making the grains more spherical modifies corrosion morphology into intergranular corrosion and corrosion surrounding spherical particles in 3 % NaCl solution. Past solution treatment, quenching at 520 °C after one hour with two weeks of natural aging transform the shape of grains into equiaxes form. Two weeks of natural aging and 30 minutes of aging at 150, 200, 250 °C after solution treatment and quenching give birth to the "Chinese script" form of the Al15(MnFe3Si intermetallic particles. The prolongation of the duration period of aging to one hour at 200 °C is sufficient to transform the morphology of corrosion into located corrosion by pitting, and a longer aging cancels the "Chinese script" form. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.1397

  7. AI-Si-Cu-Mg(-Er)铸造铝合金的低周疲劳行为%Low-Cycle Fatigue Behavior of Cast AI-Si-Cu-Mg(-Er) Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    车欣; 徐志军; 陈立佳; 徐海健; 李锋

    2011-01-01

    对金属型铸造Al-Si-Cu-Mg和Al-Si-Cu-Mg-Er铝合金进行了疲劳试验,并研究了其室温下的低周疲劳行为.试验结果表明:金属型铸造Al-Si-Cu-Mg和Al-Si-Cu-Mg-Er铝合金表现为循环应变硬化和循环稳定,主要取决于外加总应变的高低;稀土元素Er的加入可提高金属型铸造Al-Si-Cu-Mg合金的循环变形抗力和疲劳寿命;金属型铸造Al-Si-Cu-Mg合金的塑性应变、弹性应变与断裂时的载荷反向次数之间呈直线关系,Al-Si-Cu-Mg-Er合金的弹性应变与疲劳断裂时的载荷反向次数之间也呈直线关系,但其塑性应变与疲劳断裂时的载荷反向次数之间则呈双线性关系.%Through the strain-controlled fatigue experiments, the low-cycle fatigue behavior of permanent-mold cast Al-Si-Cu-Mg and Al-Si-Cu-Mg-Er alloys at room temperature was investigated.The experimental results show that the Al-Si-Cu-Mg and Al-Si-Cu-Mg-Er alloys exhibit the cyclic strain hardening and cyclic stability, mainly depending on the imposed total strain amplitude. For the permanent-mold cast Al-Si-Cu-Mg alloy, the addition of Er can effectively enhance both cyclic deformation resistance and fatigue life of the alloys. A single-slope linear relation between plastic strain amplitude, elastic strain amplitude and reversals to failure is observed for permanent-mold cast Al-Si-Cu-Mg alloy. However, a two-slope linear relation between plastic strain amplitude and reversals to failure is noted for the Al-Si-Cu-Mg-Er alloy, although the corresponding relation between elastic strain amplitude and reversals to failure is linear.

  8. 基于高温铸坯黏弹塑性的坯壳动态鼓肚研究%Research on Dynamic Bulging of Continuous Casting Slab Based on Elasto-viscoplastic Behavior of Metal at Elevated Temperature

    Institute of Scientific and Technical Information of China (English)

    韩培培; 任廷志

    2015-01-01

    基于高温铸坯材料黏弹塑性本构方程,建立了坯壳动态鼓肚数学模型。根据坯壳不同的初始状态与变形历史确定了两种边界条件。利用模型计算坯壳鼓肚变形,并与实测数据进行对比,验证了理论解的正确性以及模型的有效性。根据鞍钢工业板坯连铸机的设备工艺参数,分别计算了刚出结晶器的坯壳和远离结晶器的坯壳的鼓肚变形曲线,以及坯壳在固液交界面处的应变与应变速率。分析了铸坯坯壳在铸机扇形段内的鼓肚变形与应变变化规律,并讨论了辊间距、拉坯速度对坯壳鼓肚变形的影响。%Based on elasto-viscoplastic behavior of metal at elevated temperature,a mathematical model of dynamic bulging with the movement of the slab between two rolls was developed.According to different initial conditions and the deformation history of a solidified shell,two groups of boundary conditions were presented.Then,in order to check the validity of this mathematical model,the calcu-lated bulging profiles were compared with the measurements of bulging intensity and profiles on actual continuous casters.Then according to the casting parameters on different segments of an industrial caster in Ansteel company,the bulging of the solidified shell near mould and far from mould were ex-posed separately.In addition,the bulging features were analyzed including the bulging deflection,the bending moment acting on the solidified shell,the strain and the strain rate at the solid-liquid interface of the solidified shell.Finally,the bulging in a segment of the caster was calculated,and then the in-fluences of the casting parameters including roll pitch and casting speed were analyzed .

  9. Cross-fostering differentially affects ADHD-related behaviors in spontaneously hypertensive rats.

    Science.gov (United States)

    Gauthier, Angela C; DeAngeli, Nicole E; Bucci, David J

    2015-03-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered to an unfamiliar dam of either the same or different strain. Behavioral testing took place when the rats reached adulthood. Locomotor hyperactivity was completely dependent on the strain of the offspring. In contrast, social behavior was primarily determined by the strain of the mother, while attentional orienting behavior was influenced by both the strain of the offspring and the strain of the dam. Anxiety-related behavior was influenced by an interaction between offspring and dam strain. PMID:25647439

  10. The differential effects of depression on evoked and spontaneous pain behaviors in olfactory bulbectomized rats

    OpenAIRE

    Wang, Wei; Qi, Wei-Jing; XU, YANG; Wang, Jin-Yan; Luo, Fei

    2010-01-01

    Although it has been accepted that depression and pain are common comorbidities, their interaction is not fully understood. The current study was aimed to investigate the effects of depression on both evoked pain behavior (thermal-induced nociception) and spontaneous pain behavior (formalin pain) using an olfactory bulbectomy (OB) rat model of depression. Emotional behaviors were assessed by open field and Morris water maze tests. The results showed that the depressed rats exhibited stronger ...

  11. Effects of casting speed on microstructure and segregation of electromagnetically stirred Aluminum alloy in continuous casting process

    Institute of Scientific and Technical Information of China (English)

    LEE Dock-Young; KANG Suk-Won; CHO Duck-Ho; KIM Ki-Bae

    2006-01-01

    Recently, a semi-solid metal processing has been acknowledged as a cost-effective technique to be able to manufacture high quality product for the transportation industry.In this study a hypo-eutectic Al alloy was fabricated by means of an electromagnetic stirrer in continuous casting process and the microstructural change during solidification due to a fluid flow by electromagnetic stirring was examined.Due to the forced fluid flow during solidification a dendritic phase of primary α phase of Al alloy was turned into a globular phase, which can make the Al alloy get a thixotropic behavior in the semi-solid region.In order to establish the quantitative relationship between microstructure and the process parameters, the morphology shape, a silicon distribution and a size of primary α phase were observed according to casting speed in continuous casting machine.The primary α phase was turned into the degenerate dendrites approaching a spherical configuration with increasing casting speed.The fine-grained and equiaxed microstructure appeared at higher casting speed.A segregation behavior of Si element was declined with increasing casting speed and a very uniform distribution of Si element was observed on the billet at a casting speed of 600 mm·min-1.A thickness of the solidifying shell of the billet was shortened with increasing the casting speed.

  12. Treatment of Multiply Controlled Problem Behavior with Procedural Variations of Differential Reinforcement

    Science.gov (United States)

    Neidert, Pamela L.; Iwata, Brian A.; Dozier, Claudia L.

    2005-01-01

    We describe the assessment and treatment of 2 children with autism spectrum disorder whose problem behaviors (self-injury, aggression, and disruption) were multiply controlled. Results of functional analyses indicated that the children's problem behaviors were maintained by both positive reinforcement (attention) and negative reinforcement (escape…

  13. Differential Efficacy of Home Monitoring and Cognitive-Behavioral Treatment for Decreasing Children's Maladaptive Nighttime Fears

    Science.gov (United States)

    Pincus, Donna B.; Weiner, Courtney L.; Friedman, Alice G.

    2012-01-01

    A number of studies have demonstrated the efficacy of brief cognitive-behavioral interventions for treating childhood nighttime fears. The purpose of the present study is to determine whether behavior changes could be initiated and maintained with home monitoring and reinforcement alone. Sixteen children, ages 6 to 11, with severe, disruptive…

  14. Differential Effects of Seating Arrangements on Disruptive Behavior of Fifth Grade Students during Independent Seatwork

    Science.gov (United States)

    Bicard, David F.; Ervin, Angela; Bicard, Sara C.; Baylot-Casey, Laura

    2012-01-01

    We investigated teacher versus student seat selection in the context of group and individual seating arrangements. Disruptive behavior during group seating occurred at twice the rate when students chose their seats than when the teacher chose. During individual seating, disruptive behavior occurred more than three times as often when the students…

  15. The CAST experiment

    International Nuclear Information System (INIS)

    CAST (CERN Axion Solar Telescope) is a helioscope looking for axions coming from the solar core to the Earth. The experiment, located at CERN, is based on the Primakoff effect and uses a magnetic field of 9 Tesla provided by a decommissioned LHC magnet. CAST is able to follow the Sun during sunrise and sunset and therefore three X-ray detectors are mounted on both ends of the magnet waiting for a photon from axion-to-photon conversion due to the Primakoff effect. During its first phase, which concluded in 2004, CAST has been looking for axions with masses up to 0.02 eV. CAST's second phase manages to re-establish the coherence needed to scan for axions with masses up to 1.16 eV by using a buffer gas. This technique enables the experiment to look into the theoretical regions for axions. During the years 2005 and 2006, the use of 4He in CAST has already provided coherence in order to look for axions with masses up to 0.4 eV

  16. Differential effects of token reinforcement on instruction-following behavior in retarded students instructed as a group.

    Science.gov (United States)

    Zimmerman, E H; Zimmerman, J; Russell, C D

    1969-01-01

    This study was addressed to the problem of applying behavior modification techniques on a group basis to a class of retarded students with "attentional deficits". Seven boys, age 8 to 15 yr, characterized as showing severe "attentional" problems or disruptive behavior in their respective classrooms, participated daily for 30-min sessions in a special class over a 1.5-month period. In each session, verbal instructions were given to the class as a whole. In control sessions, each appropriate instruction-following response by a child produced praise for that child. In experimental sessions, appropriate responses also produced tokens exchangeable for tangible reinforcers after the session. Token reinforcement differentially maintained instruction-following behavior in four children while one responded appropriately to most instructions and a second improved continuously during the study. While the data suggest that the present approach can be successfully applied to the alteration of instruction-following behavior in retarded children, its major contribution may be that of providing objective quantitative information about such behavior.

  17. Mechanical behavior analysis and calculation model discussion of large span cast-in-situ floors%大跨度现浇楼盖力学性能分析及计算模型研究

    Institute of Scientific and Technical Information of China (English)

    周学军; 张慧武; 傅挺萌; 崔璐

    2015-01-01

    研究大跨度现浇楼盖的力学性能和计算模型可以更好的使其运用于工程实践。文章借助ANSYS有限元分析软件,分别对大跨度蜂巢芯砼空腹楼盖、砼叠合箱网梁楼盖和组合塑料模盒砼空心楼盖进行静力学分析,得到其挠度和应力云图;对某27 m大跨度现浇楼盖进行三维实体建模,研究其在竖向均布荷载下的受力性能,通过分析挠度和应力云图,探讨了大跨度现浇楼盖的计算模型。结果表明:三种楼盖的变形与实心板是一致的,肋间板条与肋梁的变形也基本上一致,三种楼盖的受力性能均类似于实心板,是一种“带肋的板”;27 m大跨度现浇楼盖的最大拉应力出现在楼盖板底中心处,楼盖应力分布均匀,其计算模型可以简化成实心板,整体结构可按板柱结构考虑。%Mechanical behavior and calculation model of the large-span Cast-in-situ floor were studied, which can make it better used in engineering practice. Aiming at the large span Honeycombed-core hollow floor,the concrete composite cage beam floor and the combined plastic mold boxes concrete hollow floor,static analysis was analyzed by using ANSYS finite element analysis software,which obtains their deflection and stress nephograms. A three-dimensional solid model of a 27 m large-span Cast-in-situ floor was established to study its mechanical behavior under the vertical uniformly distributed load,and its calculation model was studied by analyzing its deflection and stress nephograms. The results show:deformation of three kinds of floor are consistent with the solid plate, deformation of the floor in the middle of rib beams is consistent with rib beams,and their mechanical behavior are all similar to solid plate,which means they are actually“plates with ribs”;the first main stress of the 27m large-span Cast-in-situ floor appears in the bottom center of the floor,the stress of floor is homogeneous

  18. The differential effects of Autism and Down's syndrome on sexual behavior.

    Science.gov (United States)

    Ginevra, Maria Cristina; Nota, Laura; Stokes, Mark A

    2016-01-01

    Although sexuality plays a major role in the socialization of people, few studies have examined the sexual behaviors of individuals with developmental disabilities. Because of this, we decided to investigate sexuality in adolescents with autism spectrum disorder (ASD) and Down's syndrome (Ds) and to compare them with typically developing adolescents, by surveying their parents. Specifically, it was hypothesized that young people with ASD would display lower levels over five domains: social behavior, privacy, sex education, sexual behavior, and parental concerns, than peers with Ds and typically developing young people. In addition, we sought to verify developmental trends in five domains with age for each group. Overall, 269 parents participated; 94 parents of typically developing adolescents, 93 parents of adolescents diagnosed with Ds, and 82 parents of adolescents diagnosed with ASD. Participants were surveyed with a Sexual Behavior Scale developed by Stokes and Kaur [] that assesses parents' reports of their child's: social behavior, privacy awareness, sex education, sexual behavior and parental concerns about the child's behaviors. It was found that three groups were significantly different on all five domains, adolescents with ASD reportedly displaying lower levels than other groups. Moreover, there was a significant improvement in knowledge of privacy and parental concerns with age for adolescents with ASD and a decline in sex education for adolescents with Ds. The results obtained emphasize the need to train adolescents with developmental disability, and especially for adolescents with ASD through sex education programs.

  19. Insights into glass transition and relaxation behavior using temperature-modulated differential scanning calorimetry

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.;

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range of freque......Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range...

  20. Socioeconomic factors differentiating maternal and child health-seeking behavior in rural Bangladesh: A cross-sectional analysis

    Directory of Open Access Journals (Sweden)

    Becker Stan

    2010-04-01

    Full Text Available Abstract Background There has been an increasing availability and accessibility of modern health services in rural Bangladesh over the past decades. However, previous studies on the socioeconomic differentials in the utilization of these services were based on a limited number of factors, focusing either on preventive or on curative modern health services. These studies failed to collect data from remote rural areas of the different regions to examine the socioeconomic differentials in health-seeking behavior. Methods Data from 3,498 randomly selected currently married women from three strata of households within 128 purposively chosen remote villages in three divisions of Bangladesh were collected in 2006. This study used bivariate and multivariate logistic analyses to examine both curative and preventive health-seeking behaviors in seven areas of maternal and child health care: antenatal care, postnatal care, child delivery care, mother's receipt of Vitamin A postpartum, newborn baby care, care during recent child fever/cough episodes, and maternal coverageby tetanus toxoid (TT. Results A principal finding was that a household's relative poverty status, as reflected by wealth quintiles, was a major determinant in health-seeking behavior. Mothers in the highest wealth quintile were significantly more likely to use modern trained providers for antenatal care, birth attendance, post natal care and child health care than those in the poorest quintile (χ2, p Conclusion Within rural areas of Bangladesh, where overall poverty is greater and access to health care more difficult, wealth differentials in utilization remain pronounced. Those programs with high international visibility and dedicated funding (e.g., Immunization and Vitamin A delivery have higher overall prevalence and a more equitable distribution of beneficiaries than the use of modern trained providers for basic essential health care services. Implications of these findings and

  1. Casting Characteristics of Aluminum Die Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  2. Research on Wear Behavior of 3Cr3Mo2V Cast Steel and 3Cr13 Steel%3Cr3Mo2V铸钢和3Cr13钢磨损行为的研究

    Institute of Scientific and Technical Information of China (English)

    茅奕舒; 崔向红; 王树奇; 李冬生

    2012-01-01

    采用销盘式磨损试验机对3Cr3Mo2V铸钢和3Cr13钢在环境温度25℃和200℃下进行干滑动磨损试验,研究了显微组织和摩擦氧化物对3Cr3Mo2V铸钢和3Cr13钢磨损行为的影响,并探讨其磨损机制.结果表明:摩擦氧化物对25℃和200℃下的磨损行为和磨损机制有显著的影响,而摩擦氧化物的减磨作用取决于其数量和基体状态等,与钢的成分和显微组织密切相关.高的铬含量阻碍摩擦氧化物的形成,低硬度的回火索氏体加速氧化物剥落,故无摩擦氧化物的作用或作用降低.%Dry sliding wear tests were performed for 3Cr3Mo2V cast steel and 3Crl3 steel at 25℃ and 200 ℃ on a pin-on-disk wear tester. The effect of microstructures and tribo-oxides on the wear behavior of 3Cr3Mo2V cast steel and 3Cr13 steel was probed into and the wear mechanism was also discussed. The results show that tribo-oxides exert a significant influence on wear behavior and mechanism, and the wear reducing effect of tribo-oxides depends on their amount and substrate state that is closely related with the compositions and microstructures of the steel. High Cr content impedes the formation of tribo-oxides and tempered sorbite with low hardness accelerates the stripping of tribo-oxides, thus, the wear reducing effect of tribo-oxides is destroyed or reduced.

  3. Behavioral Differentiation Induced by Insecticide Lambda-Cyhalothrin in Mosquito Fish, Gambusia affinis

    Directory of Open Access Journals (Sweden)

    Utku GÜNER

    2016-04-01

    Full Text Available Test toxic material, one of most used pesticide, the Lambda cyhalothrin (LCY (TEKVANDO 5EC belongs to a group of chemicals called synthetic pyrethroids and pesticides and potential toxic pollutant contaminating aquatic ecosystems, was investigated in the present study for behavioral toxicology. Mosquito fish, Gambusia affinis (Baird & Girard, 1853 were selected for responses of Lambda cyhalothrin by Using to video-based movement analysis system. Selected 3 different doses 0.1, 0.5 and 0.75 ppm were used analyzed behavioral changes according to control group. The following behaviors were measured: total distance, travelled and average speed for treatment and control groups, maximum and average speed and time moving away from the dose applied point. This suggests that LCY contamination has the potential to significantly affect (p<0.05 the behavior of Mosquito fish, G. affinis.

  4. An Early Manifestation of Differential Behavior toward Children of the Same and Opposite Sex.

    Science.gov (United States)

    Wasserman, Gail A.; Stern, Daniel N.

    1978-01-01

    Assessed individual (age, sex) and dyadic (same-sex, opposite-sex) differences in approach behaviors and investigated possible explanations for such differences. The subjects were 134 White preschool children, aged three to five. (MP)

  5. Clinical differentiation between frontotemporal dementia and Alzheimers disease : Psychometric, behavioral, neuroimaging and neurophysiological information

    OpenAIRE

    Lindau, Maria

    2002-01-01

    Frontotemporal dementia (FTD) initially affects the anterior regions of the brain, and gradually spreads to other cerebral areas. Behavioral alterations are described as the hallmark of FTD, whereas cognition is mostly found to be relatively spared. Alzheimer's disease (AD) starts in the posterior brain areas, and successively involves even other regions. Typical for AD are cognitive deficits, but behavioral and emotional changes have also been reported. With progression, th...

  6. Salivary Alpha-amylase and Cortisol in Toddlers: Differential Relations to Affective Behavior

    OpenAIRE

    Fortunato, Christine K.; Dribin, Amy E.; Granger, Douglas A.; Buss, Kristin A.

    2008-01-01

    This study applies a non-invasive and multi-system measurement approach (using salivary analytes) to examine associations between the psychobiology of the stress response and affective behavior in toddlers. Eighty-seven two-year-olds (48 females) participated in laboratory tasks designed to elicit emotions and behavior ranging from pleasure/approach to fear/withdrawal. Saliva samples were collected pre-task and immediately post-task, and assayed for markers of sympathetic nervous system (alph...

  7. Cross-Fostering Differentially Affects ADHD-Related Behaviors in Spontaneously Hypertensive Rats

    OpenAIRE

    Gauthier, Angela C.; DeAngeli, Nicole E.; Bucci, David J.

    2015-01-01

    Although both genetic and non-genetic factors are known to contribute to the occurrence of Attention-Deficit Hyperactivity/Disorder (ADHD), little is known about how they impact specific symptoms. We used a cross-fostering approach with an established animal model of ADHD, the Spontaneously Hypertensive Rat strain (SHR), to test the influence of genotype and maternal behavior on ADHD-related behaviors. SHRs and their normo-active genetic relative, Wistar Kyoto rats (WKY), were cross-fostered ...

  8. Rectifying and negative differential resistance behaviors of a functionalized Tour wire: The position effects of functional groups

    Science.gov (United States)

    Kwong, Gordon; Zhang, Zhenhua; Pan, Jinbo

    2011-09-01

    Based on Tour wire, we construct four D-π-A molecular devices with different positional functional groups, in an attempt to explore the position effects of functional groups on their electronic transport properties and to show that some interesting physical phenomena can emerge by only varying the position of functional groups. The first-principles calculations demonstrate that the position of functional groups can affect the rectifying behaviors (rectification direction and ratio) significantly and determines whether or not the negative differential resistance (NDR) can be observed as well as the physical origin of the NDR phenomenon.

  9. Differentiation and Behavior of Dental Pulp Stem Cells in Hydrogel Scaffolds of Various Stiffnesses

    Science.gov (United States)

    Bhatnagar, Divya; Jurukovski, Vladimir; Rafailovich, Miriam; Simon, Marcia

    2011-03-01

    Dental Pulp Stem Cells (DPSCs) are known to differentiate in bone, dentine, or nerve tissue through different environment signals. This work investigates whether differentiation could occur in the absence of chemical induction and through mechanical stimuli only. For this study, we chose enzymatically cross-linked gelatin hydrogels as our substrates. Rheological studies carried out by oscillatory shear rheometry indicated that the modulus of the hardest hydrogel was of the order of 8kPa where as the medium and the softest hydrogel had modulus of the order of 1kPa and 100Pa respectively. DPSC were then plated on all three substrates and cultured with and without dexamethasone induction media. After 21 days of incubation, SEM analysis indicated that the cells cultured in the induction media produced biomineralized deposits on hard, medium as well as soft hydrogels. On the other hand, the cells cultured without the induction media also produced large amounts of biomineralized deposits.The modulus of the cells was also measured using AFM. En mass cell migration was also studied to determine the average velocity of migration of DPSCs. We also investigated whether stem cells that are induced to differentiate by their scaffold environment would continue to differentiate and biomineralize when removed from the inducing scaffold.

  10. Multilevel Mediation: Cumulative Contextual Risk, Maternal Differential Treatment, and Children's Behavior within Families

    Science.gov (United States)

    Meunier, Jean Christophe; Boyle, Michael; O'Connor, Thomas G.; Jenkins, Jennifer M.

    2013-01-01

    This study tests the hypothesis that links between contextual risk and children's outcomes are partially explained by differential parenting. Using multi-informant measurement and including up to four children per family (M[subscript age] = 3.51, SD = 2.38) in a sample of 397 families, indirect effects (through maternal differential…

  11. Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier.

    Science.gov (United States)

    Ishikawa, Yuki; Aonuma, Hitoshi; Sasaki, Ken; Miura, Toru

    2016-01-01

    In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral character during the course of caste differentiation. The high aggressiveness and defensive behavior is essential for colony survival, but the neurophysiological bases are completely unknown. In the present study, using the damp-wood termite Hodotermopsis sjostedti, we focused on two biogenic amines, octopamine (OA) and tyramine (TA), as candidate neuromodulators for the defensive behavior in soldiers. High-performance liquid chromatographic analysis revealed that TA levels in the brain and suboesophageal ganglion (SOG) and the OA level in brain were increased in soldiers than in pseudergates (worker caste). Immunohistochemical analysis revealed that TA/OA neurons that innervate specific areas, including the mandibular muscles, antennal nerve, central complex, suboesophageal ganglion, and thoracic and/or abdominal ganglia, were enlarged in a soldier-specific manner. Together with the results that pharmacological application of TA promoted the defensive behavior in pseudergates, these findings suggest that the increased TA/OA levels induce the higher aggressiveness and defensive behavior in termite soldiers. The projection targets of these soldier-specific enlarged TA/OA neurons may have important roles in the higher aggressiveness and defensive behavior of the termite soldiers, inducing the neuronal transition that accompanies external morphological changes. PMID:27196303

  12. Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier.

    Directory of Open Access Journals (Sweden)

    Yuki Ishikawa

    Full Text Available In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral character during the course of caste differentiation. The high aggressiveness and defensive behavior is essential for colony survival, but the neurophysiological bases are completely unknown. In the present study, using the damp-wood termite Hodotermopsis sjostedti, we focused on two biogenic amines, octopamine (OA and tyramine (TA, as candidate neuromodulators for the defensive behavior in soldiers. High-performance liquid chromatographic analysis revealed that TA levels in the brain and suboesophageal ganglion (SOG and the OA level in brain were increased in soldiers than in pseudergates (worker caste. Immunohistochemical analysis revealed that TA/OA neurons that innervate specific areas, including the mandibular muscles, antennal nerve, central complex, suboesophageal ganglion, and thoracic and/or abdominal ganglia, were enlarged in a soldier-specific manner. Together with the results that pharmacological application of TA promoted the defensive behavior in pseudergates, these findings suggest that the increased TA/OA levels induce the higher aggressiveness and defensive behavior in termite soldiers. The projection targets of these soldier-specific enlarged TA/OA neurons may have important roles in the higher aggressiveness and defensive behavior of the termite soldiers, inducing the neuronal transition that accompanies external morphological changes.

  13. Tyraminergic and Octopaminergic Modulation of Defensive Behavior in Termite Soldier

    Science.gov (United States)

    Ishikawa, Yuki; Aonuma, Hitoshi; Sasaki, Ken; Miura, Toru

    2016-01-01

    In termites, i.e. a major group of eusocial insects, the soldier caste exhibits specific morphological characteristics and extremely high aggression against predators. Although the genomic background is identical to the other non-aggressive castes, they acquire the soldier-specific behavioral character during the course of caste differentiation. The high aggressiveness and defensive behavior is essential for colony survival, but the neurophysiological bases are completely unknown. In the present study, using the damp-wood termite Hodotermopsis sjostedti, we focused on two biogenic amines, octopamine (OA) and tyramine (TA), as candidate neuromodulators for the defensive behavior in soldiers. High-performance liquid chromatographic analysis revealed that TA levels in the brain and suboesophageal ganglion (SOG) and the OA level in brain were increased in soldiers than in pseudergates (worker caste). Immunohistochemical analysis revealed that TA/OA neurons that innervate specific areas, including the mandibular muscles, antennal nerve, central complex, suboesophageal ganglion, and thoracic and/or abdominal ganglia, were enlarged in a soldier-specific manner. Together with the results that pharmacological application of TA promoted the defensive behavior in pseudergates, these findings suggest that the increased TA/OA levels induce the higher aggressiveness and defensive behavior in termite soldiers. The projection targets of these soldier-specific enlarged TA/OA neurons may have important roles in the higher aggressiveness and defensive behavior of the termite soldiers, inducing the neuronal transition that accompanies external morphological changes. PMID:27196303

  14. Experimental study of the differential effects of playing versus watching violent video games on children's aggressive behavior.

    Science.gov (United States)

    Polman, Hanneke; de Castro, Bram Orobio; van Aken, Marcel A G

    2008-01-01

    There is great concern about the effects of playing violent video games on aggressive behavior. The present experimental study was aimed at investigating the differential effects of actively playing vs. passively watching the same violent video game on subsequent aggressive behavior. Fifty-seven children aged 10-13 either played a violent video game (active violent condition), watched the same violent video game (passive violent condition), or played a non-violent video game (active non-violent condition). Aggression was measured through peer nominations of real-life aggressive incidents during a free play session at school. After the active participation of actually playing the violent video game, boys behaved more aggressively than did the boys in the passive game condition. For girls, game condition was not related to aggression. These findings indicate that, specifically for boys, playing a violent video game should lead to more aggression than watching television violence. PMID:18161877

  15. Differential reinforcement of other behavior and noncontingent reinforcement as control procedures during the modification of a preschooler's compliance.

    Science.gov (United States)

    Goetz, E M; Holmberg, M C; LeBlanc, J M

    1975-01-01

    Differential reinforcement of other behavior (DRO) and noncontingent reinforcement were compared as control procedures during the modification of a 3-yr-old preschooler's compliance. The recorded reinforcer was teacher proximity (within 3 ft (0.9) of the subject for at least 5 sec) which was often accompanied by positive verbal comments that varied in content across experimental conditions. The verabal content during contingent reinforcement might have been: "Thank you for picking up the blocks"; during non-contingent reinforcement: "You're wearing a pretty dress"; and during DRO: "I don't blame you for not picking up because it isn't any fun". Contingent reinforcement increased compliance in all manipulation conditions. Noncontingent reinforcement decreased compliance during two reversal conditions. However, the behavior was variable and did not decrease to the low levels reached during the two DRO reversals.

  16. Strip casting of stainless steels

    OpenAIRE

    Raabe, D.

    1997-01-01

    FLAT PRODUCTS OF STAINLESS STEELS ARE CONVENTIONALLY MANUFACTURED BY CONTINUOUS CASTING, HOT ROLLING, HOT BAND ANNEALING, PICKLING, COLD ROLLING AND RECRYSTALLISATION. IN THE LAST YEARS STRIP CASTING HAS INCREASINGLY ATTRACTED ATTENTION. IT OFFERS THREE IMPROVEMENTS IN COMPARISON TO THE CONVENTIONAL METHOD.1.) IT ALLOWS TO CAST STEEL SHEETS WITH THE SAME THICKNESS AND WIDTH AS THOSE PRODUCED BY HOT ROLLING. THIS MEANS THAT THE HOT ROLLING PROCESSIS BYPASSED. 2.) THE STRIP CAST STEEL REVEALS A...

  17. EPG Recordings Reveal Differential Feeding Behaviors in Sogatella furcifera in Response to Plant Virus Infection and Transmission Success.

    Science.gov (United States)

    Lei, Wenbin; Li, Pei; Han, Yongqiang; Gong, Shaolong; Yang, Lang; Hou, Maolin

    2016-01-01

    Plant viruses are primarily transmitted by insect vectors and virus infection may influence on the vectors' feeding behaviors. Using an electrical penetration graph, we detected that infection with the Southern rice black-streaked dwarf virus (SRBSDV) in the white-backed planthopper (WBPH) and in rice plants both altered the vector's feeding behavior. When viruliferous WBPH (carrying SRBSDV) were fed on uninfected plants, they spent more time in salivation and phloem sap ingestion than non-viruliferous insects. In comparison with uninfected plants, infected plants showed an arrestant effect on non-viruliferous WBPH for phloem sap ingestion. Differential feeding behaviors were also detected between the WBPH that inoculated or acquired SRBSDV and those that failed to. The WBPH that inoculated SRBSDV exhibited more probing bouts, salivation events and phloem sap ingestion events and longer salivation than those that failed to. The WBPH that acquired SRBSDV were quicker to reach phloem and spent more time in phloem sap ingestion than those that failed to. These behavior alterations in the vector may have adaptive advantages for SRBSDV transmission and spread success because greater salivation by viruliferous vectors on uninfected hosts will promote virus inoculation, whereas more sap ingestion by non-viruliferous vectors on infected hosts will promote virus acquisition. PMID:27492995

  18. Fired up or burned out? How developmental challenge differentially impacts leader behavior.

    Science.gov (United States)

    Courtright, Stephen H; Colbert, Amy E; Choi, Daejeong

    2014-07-01

    Leadership development research has largely drawn on experiential and enactive learning theories to explore the positive effects of developmental challenge on leaders. In contrast, we examined potential positive and negative effects of developmental challenge (i.e., challenging job assignments) on leader behavior through an alternative theoretical lens--transactional stress theory. We predicted, on one hand, that developmental challenge may be associated with higher leader engagement and transformational leadership behavior; however, developmental challenge also has the potential to be associated with higher leader emotional exhaustion and laissez-faire leadership behavior. We further proposed that leadership self-efficacy (LSE) moderates these potential effects of developmental challenge and helps explain why leaders react either positively or negatively to developmental challenge. We tested our hypotheses in a sample of 153 leaders and 631 direct reports at a Fortune 500 company. Findings supported positive relationships among developmental challenge, leader engagement, and transformational leadership. However, we also found support for significant relationships among developmental challenge, emotional exhaustion, and laissez-faire leadership. Additionally, leaders lower in LSE were more likely to encounter the negative effects of developmental challenge by experiencing increased emotional exhaustion and displaying laissez-faire leadership behaviors. Our study contributes to theory and practice by elucidating a "dark side" of developmental challenge, identifying LSE as a moderator of the negative effects of developmental challenge, identifying antecedents of transformational and laissez-faire leadership behaviors, and investigating demands and stress in leadership roles. PMID:24490967

  19. Scheduled Caste Women: Problems And Challenges

    OpenAIRE

    Vijayakumar Murthy; Jaikishan Thakur

    2013-01-01

    The paper analyzed the Caste system based on Varnas during the ancient India. It also examined the demerits of caste attached to the present scheduled castes in general and scheduled caste women in particular. The scheduled caste women are disadvantaged by their caste and gender and as such they are subject to exploitation and discrimination by their family members, by their caste people and by forward castes. Hence, there is increase in exploitation, discrimination and violence against the s...

  20. Extrusion cast explosive

    Science.gov (United States)

    Scribner, Kenneth J.

    1985-01-01

    Improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst are disclosed. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants.

  1. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Ph.D Liu Jincheng

    2010-01-01

    @@ Note: This book consists of five sections: Chapter 1 Introduction, Chapter 2 Grey Iron, Chapter 3 Spheroidal Graphite Cast Iron, Chapter 4 Vermicular Cast Iron, and Chapter 5 White Cast Iron. CHINA FOUNDRY publishes this book in several parts serially, starting from the first issue of 2009.

  2. Mix/Cast Contamination Control

    Science.gov (United States)

    Wallentine, M.

    2005-01-01

    Presented is a training handbook for Mix/Cast Contamination Control; a part of a series of training courses to qualify access to Mix/Cast facilities. Contents: List Contamination Control Requirements; Identify foreign objects debris (FOD), Control Areas and their guidelines; Describe environmental monitoring; List Contamination Control Initiatives; Describe concern for Controlled Materials; Identify FOD Controlled Areas in Mix/Cast.

  3. Conspicuous Consumption versus Charitable Behavior in Response to Social Exclusion: A Differential Needs Explanation

    OpenAIRE

    Jaehoon Lee; L. J. SHRUM

    2012-01-01

    Social exclusion has been shown to produce a number of different responses. This research examines the proposition that social exclusion may produce either self-focused or prosocial responses, depending on which needs are threatened. Different types of social exclusion threaten different needs, which in turn produce distinct outcomes (differential needs hypothesis). Social exclusion in the form of being implicitly ignored increased conspicuous consumption, whereas being explicitly rejected in...

  4. Based on database and asp.net technologies, a web platform of scientific data in the casting forces on the mold-fi lling behavior of titanium melts in vertically rotating molds

    Directory of Open Access Journals (Sweden)

    Xu Daming

    2008-11-01

    Full Text Available The vertical centrifugal-casting technique is widely used in the manufacture of various irregularlyshaped castings of advanced structural alloys with thin walls, complex shapes and/or large sizes. These castings are used in the increasing applications in aero-space/aviation industries, human teeth/bone repairs with nearnet shaped components, etc. In a vertically rotating casting system, the mold-filling processes of alloy melts, coupled with solidifi cation-heat transfer, may be much more complicated, because they are driven simultaneously by gravity, centrifugal and Coriolis forces. In the present work, an N-S/VOF-equations-based model, solved using a SOLA-VOF algorithm, under a rotating coordinate system was applied to numerically investigate the impacts of centrifugal and Coriolis forces on metallic melt mold-fi lling processes in different vertical centrifugal-casting configurations with different mold-rotation rates using an authors’ computer-codes system. The computational results show that the Coriolis force may cause remarkable variations in the fl ow patterns in the casting-part-cavities of a large horizontal-section area and directly connected to the sprue via a short ingate in a vertical centrifugalcasting process. A “turn-back” mold-filling technique, which only takes advantage of the centrifugal force in a transient rotating melt system, has been confi rmed to be a rational centrifugal-casting process in order to achieve smooth and layer-by-layer casting-cavities-fi lling control. The simulated mold-fi lling processes of Ti-6Al-4V alloy melt, in a vertical centrifugal-casting system with horizontally-connected plate-casting cavities, show reasonable agreement with experimental results from the literature.

  5. Differential osmotic behavior of water components in living skeletal muscle resolved by 1H-NMR.

    Science.gov (United States)

    Kimura, Masako; Takemori, Shigeru; Yamaguchi, Maki; Umazume, Yoshiki

    2005-08-01

    Using frog sartorius muscle, we observed transverse relaxation processes of (1)H-NMR signals from myowater. The process could be well described by four characteristic exponentials: the extremely slow exponential of relaxation time constant T(2) > 0.4 s, the slow one of T(2) approximately 0.15 s, the intermediate one of 0.03 s isotonic extracellular solution affected only the extremely slow exponential, linearly increasing its amplitude and gradually increasing its T(2) toward that of the bulk solution (1.7 s). Therefore, this exponential should represent extracellular surplus solution independently of the other exponentials. At two thirds to three times the isotonicity, the amplitude of the intermediate exponential showed normal osmotic behavior in parallel with the volume change of the myofilament lattice measured with x-ray diffraction. In the same tonicity range, the amplitude of the rapid exponential showed converse osmotic behavior. Lower tonicities increased the amplitude of only the slow exponential. Studied tonicities did not affect the T(2) values. The distinct osmotic behavior indicated that each characteristic exponential could be viewed as a distinct water group. In addition, the converse osmotic behavior suggested that the rapid exponential would not be a static water layer on the macromolecule surface. PMID:15894647

  6. Differential behavioral responses of two plant-parasitic nematodes to biogenic amines

    Science.gov (United States)

    Hatching and infective juvenile (J2) behavior in two species of plant-parasitic nematodes, Heterodera glycines and Meloidogyne incognita, were affected by in vitro treatment with the biogenic amines dopamine, octopamine, and serotonin. While the overall responses of each species to amine exposures w...

  7. Differential Effects of a Food-Based Conditioned Inhibitor on Food- or Cocaine-Seeking Behavior

    Science.gov (United States)

    Lombas, Andres S.; Kearns, David N.; Weiss, Stanley J.

    2008-01-01

    The present experiment compared the effects of a food-based conditioned inhibitor on food seeking vs. cocaine seeking behavior. In two groups of rats, the A+/AB- Pavlovian conditioned inhibition procedure was used to create a conditioned inhibitor for food. Then, for one group of rats (Food-Food Group), a click stimulus was established as an…

  8. A Practitioner's Guide to Implementing a Differential Reinforcement of Other Behaviors Procedure

    Science.gov (United States)

    Gongola, Leah C.; Daddario, Rosemarie

    2010-01-01

    The use of interventions to create behavior change among students with disabilities has an extended and complex history (Horner et al., 2005). Practitioners involved in the field of special education often debate best practices from an immense array of available interventions (Heflin & Simpson, 1998). Service providers express concern about…

  9. Social Behavior in Interacting Squirrel Monkeys with Differential Nutritional and Environmental Histories.

    Science.gov (United States)

    Chappell, Patricia F.

    This paper reports an observational study of the effects of handling on the social behavior of squirrel monkeys who received a protein deficient diet. After birth, experimental animals received a low-protein diet for a 6-week period. A subgroup of these animals were handled between 3 and 12 weeks of age. All of the animals interacted (in four…

  10. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2010-01-01

    @@ Chapter 3 Spheroidal Graphite Cast Iron(I) Spheroidal Graphite Cast Iron, SG iron in short, refers to the cast iron in which graphite precipitates as spheroidal shape during solidification of liquid iron. The graphite in common commercial cast iron can only be changed from flake to spheroidal shape by spheroidising treatment. Since spheroidal graphite reduces the cutting effect of stress concentration, the metal matrix strength of SG iron can be applied around 70%-90%, thus the mechanical property of SG iron is significantly superior to other cast irons;even the tensile strength of SG iron is higher than that carbon steel.

  11. Differential Rearing Alters Forced Swim Test Behavior, Fluoxetine Efficacy, and Post-Test Weight Gain in Male Rats.

    Science.gov (United States)

    Arndt, David L; Peterson, Christy J; Cain, Mary E

    2015-01-01

    Environmental factors play a key role in the etiology of depression. The rodent forced swim test (FST) is commonly used as a preclinical model of depression, with increases in escape-directed behavior reflecting antidepressant effects, and increases in immobility reflecting behavioral despair. Environmental enrichment leads to serotonergic alterations in rats, but it is unknown whether these alterations may influence the efficacy of common antidepressants. Male Sprague-Dawley rats were reared in enriched (EC), standard (SC), or isolated (IC) conditions. Following the rearing period, fluoxetine (10 or 20 mg/kg, i.p.) was administered 23.5 hrs, 5 hrs, and 1 hr before locomotor and FST measures. Following locomotor testing and FST exposure, rats were weighed to assess fluoxetine-, FST-, and environmental condition-induced moderations in weight gain. Results revealed an antidepressant effect of environmental enrichment and a depressant effect of isolation. Regardless of significant fluoxetine effects on locomotor activity, fluoxetine generally decreased swimming and increased immobility in all three environmental conditions, with IC-fluoxetine (10 mg/kg) rats and EC-fluoxetine (20 mg/kg) rats swimming less than vehicle counterparts. Subchronic 20 mg/kg fluoxetine also induced significant weight loss, and differential rearing appeared to moderate weight gain following FST stress. These results suggest that differential rearing has the ability to alter FST behaviors, fluoxetine efficacy, and post-stressor well-being. Moreover, 20 mg/kg fluoxetine, administered subchronically, may lead to atypical effects of those commonly observed in the FST, highlighting the importance and impact of both environmental condition and dosing regimen in common animal models of depression.

  12. Morphological Caste Differences in Three Species of the Neotropical Genus Clypearia (Hymenoptera: Polistinae: Epiponini

    Directory of Open Access Journals (Sweden)

    Giovanna Tocchini Felippotti

    2010-01-01

    Full Text Available Clypearia is a rare genus of swarm-founding Neotropical wasp whose biology is very little known. Morphological castes differences, condition of ovaries, relative age, and color pattern differences were analyzed in three species of Clypearia. Physiological differences and low morphometric differentiation between queens and workers were present in all species studied, indicating that these species are characterized by “physiological caste only”. We suggest that caste determination in the three Clypearia species studied is postimaginal.

  13. Morphological Caste Differences in Three Species of the Neotropical Genus Clypearia (Hymenoptera: Polistinae: Epiponini)

    OpenAIRE

    Giovanna Tocchini Felippotti; Lucas Mateus; Sidnei Mateus; Fernando Barbosa Noll; Ronaldo Zucchi

    2010-01-01

    Clypearia is a rare genus of swarm-founding Neotropical wasp whose biology is very little known. Morphological castes differences, condition of ovaries, relative age, and color pattern differences were analyzed in three species of Clypearia. Physiological differences and low morphometric differentiation between queens and workers were present in all species studied, indicating that these species are characterized by “physiological caste only”. We suggest that caste determination in the three ...

  14. Population dynamics under selection and mutation: Long-time behavior for differential equations in measure spaces

    Science.gov (United States)

    Ackleh, Azmy S.; Cleveland, John; Thieme, Horst R.

    2016-07-01

    We study the long-time behavior of solutions to a measure-valued selection-mutation model that we formulated in [14]. We establish permanence results for the full model, and we study the limiting behavior even when there is more than one strategy of a given fitness; a case that arises in applications. We show that for the pure selection case the solution of the dynamical system converges to a Dirac measure centered at the fittest strategy class provided that the support of the initial measure contains a fittest strategy; thus we term this Dirac measure an Asymptotically Stable Strategy. We also show that when the strategy space is discrete, the selection-mutation model with small mutation has a locally asymptotically stable equilibrium that attracts all initial conditions that are positive at the fittest strategy.

  15. Differential Effects of TRPA and TRPV Channels on Behaviors of Caenorhabditis elegans

    Science.gov (United States)

    Thies, Jennifer; Neutzler, Vanessa; O’Leary, Fidelma; Liu, He

    2016-01-01

    TRPA and TRPV ion channels are members of the transient receptor potential (TRP) cation channel superfamily, which mediates various sensory transductions. In Caenorhabditis elegans, the TRPV channels are known to affect chemosensation, while the TRPA-1 channel is associated with thermosensation and mechanosensation. We examined thermosensation, chemosensation, and osmosensation in strains lacking TRPA-1 or TRPV channels. We found that TRPV channel knockout worms exhibited similar behavioral deficits associated with thermotaxis as the TRPA-1 channel knockout, suggesting a dual role for TRPV channels. In contrast, chemosensation responses, assessed by both avoidance reversal behavior and NaCl osmosensation, were dependent on TRPV channels but seemed independent of TRPA-1 channel. Our findings suggest that, in addition to TRPA-1 channel, TRPV channels are necessary for thermotaxis and may activate, or modulate, the function of TRPA-1 channels. In contrast, TRPA-1 channels do not have a dual responsibility, as they have no functional role in odorant avoidance or osmosensation. PMID:27168724

  16. Differential effects of gamification, nudging and rational information on travel behavior

    DEFF Research Database (Denmark)

    Lieberoth, Andreas; Jensen, Niels Holm; Skovgaard, Thomas;

    Evidence for the efficacy of gamification is still mixed, and effect data are rarely gathered in a manner that allows comparison to other equally popular behavior design approaches. This study therefore tested the relative effects of gamification, nudging and rational information as means...... to change human behavior by just-in-time choice situations so as to invite the preferred options, than though rational–just-in-case information (Lieberoth & Jensen, 2016). The guiding premise is that humans are cognitive misers, who rely on fast and frugal heuristics instead of considering our options...... rationally, leaving us wide open to small situational “nudges” most of the time. The evidence base from highly diverse nudge interventions, however, comprises many studies with small effects and methodological issues (Bucher et al., 2016; Marteau, Ogilvie, Roland, Suhrcke, & Kelly, 2011), perhaps reflecting...

  17. Differential Effects of TRPA and TRPV Channels on Behaviors of Caenorhabditis elegans.

    Science.gov (United States)

    Thies, Jennifer; Neutzler, Vanessa; O'Leary, Fidelma; Liu, He

    2016-01-01

    TRPA and TRPV ion channels are members of the transient receptor potential (TRP) cation channel superfamily, which mediates various sensory transductions. In Caenorhabditis elegans, the TRPV channels are known to affect chemosensation, while the TRPA-1 channel is associated with thermosensation and mechanosensation. We examined thermosensation, chemosensation, and osmosensation in strains lacking TRPA-1 or TRPV channels. We found that TRPV channel knockout worms exhibited similar behavioral deficits associated with thermotaxis as the TRPA-1 channel knockout, suggesting a dual role for TRPV channels. In contrast, chemosensation responses, assessed by both avoidance reversal behavior and NaCl osmosensation, were dependent on TRPV channels but seemed independent of TRPA-1 channel. Our findings suggest that, in addition to TRPA-1 channel, TRPV channels are necessary for thermotaxis and may activate, or modulate, the function of TRPA-1 channels. In contrast, TRPA-1 channels do not have a dual responsibility, as they have no functional role in odorant avoidance or osmosensation. PMID:27168724

  18. Psychological and Behavioral Characteristics Differentiating Gang and Non-gang Girls in the UK

    OpenAIRE

    Alleyne, Emma; Pritchard, E.

    2015-01-01

    Purpose: Research has demonstrated that girls are involved in gangs as members and affiliates. However, the psychological processes related to female gang membership has, to date, not been examined using a rigorous comparative design. The main purpose of this study was to assess whether female gang members exhibit distinct psychological and behavioral features when compared to female non-gang youth. Design/methodology/approach: 117 female students were recruited from all-girls’ secondary...

  19. Differential Behavior of Young Eucalyptus Clones in Response to Nitrogen Supply

    Directory of Open Access Journals (Sweden)

    Eric Victor de Oliveira Ferreira

    2015-06-01

    Full Text Available Eucalyptus requires large amounts of nitrogen (N; however, it responds in diverse manners to the application of this nutrient. The aim of this study was to evaluate the differential performance in growth, mineral nutrition, and gas exchanges of N-fertilized Eucalyptus clones. The treatments consisted of two Eucalyptus clones (VM-01 and I-144 and six N application rates (0, 0.74, 2.93, 4.39, 5.85, and 8 mmol L-1 NH4NO3 arranged in a randomized complete block design with five replications. VM-01 had greater plant height and greater height/collar diameter ratio, as well as higher leaf concentrations of all macronutrients and of Cu, Fe, Mo, and Zn. In terms of total and root dry matter production, root/shoot ratio, and collar diameter, as well as stomatal conductance and transpiration, I-144 performed better. The performance of the clones was clearly differentiated, and the growth of I-144, despite lower leaf N concentration, was in general better than VM-01.

  20. Effects of ecological differentiation on Lotka-Volterra systems for species with behavioral adaptation and variable growth rates.

    Science.gov (United States)

    Lacitignola, D; Tebaldi, C

    2005-03-01

    We study the properties of a n2-dimensional Lotka-Volterra system describing competing species that include behaviorally adaptive abilities. We indicate as behavioral adaptation a mechanism, based on a kind of learning, which is not viewed in the evolutionary sense but is intended to occur over shorter time scales. We consider a competitive adaptive n species Lotka-Volterra system, n > or = 3, in which one species is made ecologically differentiated with respect to the others by carrying capacity and intrinsic growth rate. The symmetry properties of the system and the existence of a certain class of invariant subspaces allow the introduction of a 7-dimensional reduced model, where n appears as a parameter, which gives full account of existence and stability of equilibria in the complete system. The reduced model is effective also in describing the time-dependent regimes for a large range of parameter values. The case in which one species has a strong ecological advantage (i.e. with a carrying capacity higher than the others), but with a varying growth rate, has been analyzed in detail, and time-dependent behaviors have been investigated in the case of adaptive competition among four species. Relevant questions, as species survival/exclusion, are addressed focusing on the role of adaptation. Interesting forms of species coexistence are found (i.e. competitive stable equilibria, periodic oscillations, strange attractors).

  1. Melting and casting of FeAl-based cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K. [Oak Ridge National Lab., TN (United States); Wilkening, D. [Columbia Falls Aluminum Co., Columbia Falls, MT (United States); Liebetrau, J.; Mackey, B. [AFFCO, L.L.C., Anaconda, MT (United States)

    1998-11-01

    The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the effect of chemistry on the microstructure and hardness of castings. It is concluded that the use of the Exo-Melt{trademark} process for melting and the proper selection of the aluminum melt stock can result in porosity-free castings. The FeAl alloys can be melted and cast from the virgin and revert stock. A large variation in carbon content of the alloys is possible before the precipitation of graphite flakes occurs. Titanium is a very potent addition to refine the grain size of castings. A range of complex sand castings and two different sizes of centrifugal cast tubes of the alloy have already been cast.

  2. Melting and casting of FeAl-based cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Wilkening, D. [Columbia Falls Aluminum Co., 2000 Aluminum Dr., Columbia Falls, MT 59912 (United States); Liebetrau, J.; Mackey, B. [AFFCO, L.L.C., P.O. Box 1071, Anaconda, MT 59711 (United States)

    1998-12-31

    The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the effect of chemistry on the microstructure and hardness of castings. It is concluded that the use of the Exo-Melt{sup TM} process for melting and the proper selection of the aluminum melt stock can result in porosity-free castings. The FeAl alloys can be melted and cast from the virgin and revert stock. A large variation in carbon content of the alloys is possible before the precipitation of graphite flakes occurs. Titanium is a very potent addition to refine the grain size of castings. A range of complex sand castings and two different sizes of centrifugal cast tubes of the alloy have already been cast. (orig.) 18 refs.

  3. Varying social media post types differentially impacts engagement in a behavioral weight loss intervention.

    Science.gov (United States)

    Hales, Sarah B; Davidson, Charis; Turner-McGrievy, Gabrielle M

    2014-12-01

    The purpose of this study was to examine whether different types of posts differentially affect participant engagement and if engagement with social media enhances weight loss. Data are a subanalysis from a randomized weight loss study with a 4-month follow-up support period via private Facebook groups and monthly meetings. Counselors posted five different post types/week based on social cognitive theory (weight-related, recipes, nutrition information, poll votes, or requests for suggestions). Types of participant engagement (likes, comments/poll votes, and views) were assessed. Poll votes were the most engaging (mean number of votes or comments/poll 14.6 ± 3.4, P social support during weight loss interventions using remote methodology. PMID:25584084

  4. Deletion of TDO2, IDO-1 and IDO-2 differentially affects mouse behavior and cognitive function.

    Science.gov (United States)

    Too, Lay Khoon; Li, Kong M; Suarna, Cacang; Maghzal, Ghassan J; Stocker, Roland; McGregor, Iain S; Hunt, Nicholas H

    2016-10-01

    Tryptophan, an amino acid involved in routine energy metabolism, is a key modulator of sickness behaviors associated with inflammatory states and also plays roles in some psychiatric disorders. Tissue concentrations of tryptophan are regulated primarily by the enzymes indoleamine 2,3-dioxygenase 1 (IDO1), IDO2 and tryptophan 2,3-dioxygenase (TDO, encoded by TDO2). Altered IDO1 and TDO activities have been linked to the perturbed serotonergic neurotransmission that may underlie certain psychopathologies. Here we assessed mice genetically modified to be deficient in IDO1, IDO2 or TDO2 for their behavior and cognitive function using an automated home cage system, the IntelliCage™. A well-established behavioural and cognitive test battery was applied during two periods (Runs 1 and 2, "R1" and "R2") separated by one month. Various tryptophan-related neurochemicals also were measured in brain extracts. IDO1(-/-) mice displayed remarkable reductions of early diurnal exploration in the IntelliCage and this persisted in R2. In contrast, early diurnal hyperactivity was observed in IDO2(-/-) mice in both R1 and R2. TDO2(-/-) mice displayed increased diurnal and nocturnal exploration, but only in R2. Cognitive assessment suggested enhanced reference memory in IDO2(-/-) mice in a complex patrolling task, while TDO deficiency was associated with enhanced performance in complex patrolling and discrimination reversal tasks. Neurochemical measures showed attenuated brain serotonin levels in IDO1(-/-) mice and augmented tryptophan and serotonin levels in TDO2(-/-) animals, respectively. No neurochemical alterations were detected in IDO2(-/-) mice. Taken together, these findings reveal complex and dissimilar patterns of behavioral and cognitive changes induced by knockout of three different tryptophan-metabolizing enzymes. PMID:27316339

  5. Characterization of Ni–Cr alloys using different casting techniques and molds

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Teng, Fu-Yuan [Department of Dentistry, Kaohsiung Armed Forces General Hospital, Kaohsiung 802, Taiwan (China); School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Hung, Chun-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China)

    2014-02-01

    This study differentiated the mechanical properties of nickel–chromium (Ni–Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni–Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, “casting mold,” significantly influenced all mechanical properties. The graphite mold casting of the Ni–Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni–Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. - Highlights: • Properties of Ni–Cr alloys using various casting techniques are characterized. • Alloys cast by graphite mold exhibited higher recovery angle and more ductility. • Alloys cast by graphite mold exhibited higher strength and grinding rate. • Alloys in this study increase operative room to adjust the precision for prosthesis.

  6. Light metal compound casting

    Institute of Scientific and Technical Information of China (English)

    Konrad J.M.PAPIS; Joerg F.LOEFFLER; Peter J.UGGOWITZER

    2009-01-01

    'Compound casting'simplifies joining processes by directly casting a metallic melt onto a solid metal substrate. A continuously metallurgic transition is very important for industrial applications, such as joint structures of spaceframe constructions in transport industry. In this project, 'compound casting' of light metals is investigated, aiming at weight-saving. The substrate used is a wrought aluminium alloy of type AA5xxx, containing magnesium as main alloying element. The melts are aluminium alloys, containing various alloying elements (Cu, Si, Zn), and magnesium. By replacing the natural oxygen layer with a zinc layer, the inherent wetting difficulties were avoided, and compounds with flawless interfaces were successfully produced (no contraction defects, cracks or oxides). Electron microscopy and EDX investigations as well as optical micrographs of the interfacial areas revealed their continu-ously metallic constitution. Diffusion of alloying elements leads to heat-treatable microstructures in the vicinity of the joining interfaces in Al-Al couples. This permits significant variability of mechanical properties. Without significantly cutting down on wettability, the formation of low-melting intermetallic phases (Al3Mg2 and AI12Mg17 IMPs) at the interface of Al-Mg couples was avoided by applying a protec-tive coating to the substrate.

  7. The Effects of a Brief Acceptance-based Behavior Therapy vs. Traditional Cognitive Behavior Therapy for Public Speaking Anxiety: Differential Effects on Performance and Verbal Working Memory

    Science.gov (United States)

    Glassman, Lisa Hayley

    ), as well as an improvement in speech performance regardless of intervention received. While not statistically significant, participants who received an acceptance-based intervention exhibited larger improvements in observer-rated speech performance at post-treatment in comparison to tCBT (F (1,21) = 1.91, p =.18, etap2 = .08) such that individuals in the ABBT condition exhibited a considerably greater improvement in observer-rated speech performance than those in the tCBT condition. There was no differential impact of treatment condition on subjective speech anxiety or working memory task performance. Potential mediators and moderators of treatment were also examined. Results provide support for a brief 90-minute intervention for public speaking anxiety, but more research is needed in a study with a larger sample to fully understand the relationship between ABBT strategies and improvements in behavioral performance.

  8. Differential dynamic behaviors of undulatory nematodes in liquid vs. soft gel environment

    Science.gov (United States)

    Park, Jin-Sung; Shin, Jennifer H.

    2015-03-01

    Caenorhabditis elegans (C. elegans) is an undulatory nematode which exhibits two distinct locomotion types of swimming and crawling. Although in its natural habitat C. elegans lives in complex fluidic environment, our current understanding has been limited to the behavior of C. elegans in a simple Newtonian fluid. Here, we present some experimental results on the penetrating behavior of C. elegans at the interface from liquid to solid environment. Once C. elegans, which otherwise swims freely in a liquid, makes a contact to the solid gel boundary, it begins to penetrate vertically to the surface by changing its stroke motion characterized by a stiffer body shape and a slow stroke frequency. The particle image velocimetry (PIV) analysis reveals the flow streamlines produced by the stroke of worm. For the worm that crawls on a solid surface, we utilize a technique of traction force microscopy (TFM) to find that the crawling nematode forms localized force islands along the body where makes direct contacts to the gel surface. This work was supported by the National Research Foundation (NRF) Grant 2013R1A1A2012420 and 2010-0016886.

  9. Bimetallic layered castings alloy steel – carbon cast steel

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2011-01-01

    Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast processso-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic carbon cast steel, whereas working part (layer is plate of austenitic alloy steel sort X10CrNi 18-8. The ratio of thickness between bearing and working part is 8:1. The quality of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches.

  10. Casting larger polycrystalline silicon ingots

    Energy Technology Data Exchange (ETDEWEB)

    Wohlgemuth, J.; Tomlinson, T.; Cliber, J.; Shea, S.; Narayanan, M.

    1995-08-01

    Solarex has developed and patented a directional solidification casting process specifically designed for photovoltaics. In this process, silicon feedstock is melted in a ceramic crucible and solidified into a large grained semicrystalline silicon ingot. In-house manufacture of low cost, high purity ceramics is a key to the low cost fabrication of Solarex polycrystalline wafers. The casting process is performed in Solarex designed casting stations. The casting operation is computer controlled. There are no moving parts (except for the loading and unloading) so the growth process proceeds with virtually no operator intervention Today Solarex casting stations are used to produce ingots from which 4 bricks, each 11.4 cm by 11.4 cm in cross section, are cut. The stations themselves are physically capable of holding larger ingots, that would yield either: 4 bricks, 15 cm by 15 an; or 9 bricks, 11.4 cm by 11.4 an in cross-section. One of the tasks in the Solarex Cast Polycrystalline Silicon PVMaT Program is to design and modify one of the castings stations to cast these larger ingots. If successful, this effort will increase the production capacity of Solarex`s casting stations by 73% and reduce the labor content for casting by an equivalent percentage.

  11. Central & peripheral glucagon-like peptide-1 receptor signaling differentially regulate addictive behaviors.

    Science.gov (United States)

    Sirohi, Sunil; Schurdak, Jennifer D; Seeley, Randy J; Benoit, Stephen C; Davis, Jon F

    2016-07-01

    Recent data implicate glucagon-like peptide-1 (GLP-1), a potent anorexigenic peptide released in response to nutrient intake, as a regulator for the reinforcing properties of food, alcohol and psychostimulants. While, both central and peripheral mechanisms mediate effects of GLP-1R signaling on food intake, the extent to which central or peripheral GLP-1R signaling regulates reinforcing properties of drugs of abuse is unknown. Here, we examined amphetamine reinforcement, alcohol intake and hedonic feeding following peripheral administration of EX-4 (a GLP-1 analog) in FLOX and GLP-1R KD(Nestin) (GLP-1R selectively ablated from the central nervous system) mice (n=13/group). First, the effect of EX-4 pretreatment on the expression of amphetamine-induced conditioned place preference (Amp-CPP) was examined in the FLOX and GLP-1R KD(Nestin) mice. Next, alcohol intake (10% v/v) was evaluated in FLOX and GLP-1R KD(Nestin) mice following saline or EX-4 injections. Finally, we assessed the effects of EX-4 pretreatment on hedonic feeding behavior. Results indicate that Amp-CPP was completely blocked in the FLOX mice, but not in the GLP-1R KD(Nestin) mice following EX-4 pretreatment. Ex-4 pretreatment selectively blocked alcohol consumption in the FLOX mice, but was ineffective in altering alcohol intake in the GLP-1R KD(Nestin) mice. Notably, hedonic feeding was partially blocked in the GLP-1R KD(Nestin) mice, whereas it was abolished in the FLOX mice. The present study provides critical insights regarding the nature by which GLP-1 signaling controls reinforced behaviors and underscores the importance of both peripheral and central GLP-1R signaling for the regulation of addictive disorders. PMID:27072507

  12. Differentiation of rodent behavioral phenotypes and methylphenidate action in sustained and flexible attention tasks.

    Science.gov (United States)

    Chu, Richard; Shumsky, Jed; Waterhouse, Barry D

    2016-06-15

    Methyphenidate (MPH) is the primary drug treatment of choice for ADHD. It is also frequently used off-label as a cognitive enhancer by otherwise healthy individuals from all age groups and walks of life. Military personnel, students, and health professionals use MPH illicitly to increase attention and improve workplace performance over extended periods of work activity. Despite the frequency of its use, the efficacy of MPH to enhance cognitive function across individuals and in a variety of circumstances is not well characterized. We sought to better understand MPH׳s cognitive enhancing properties in two different rodent models of attention. We found that MPH could enhance performance in a sustained attention task, but that its effects in this test were subject dependent. More specifically, MPH increased attention in low baseline performing rats but had little to no effect on high performing rats. MPH exerted a similar subject specific effect in a test of flexible attention, i.e. the attention set shifting task. In this test MPH increased behavioral flexibility in animals with poor flexibility but impaired performance in more flexible animals. Overall, our results indicate that the effects of MPH are subject-specific and depend on the baseline level of performance. Furthermore, good performance in in the sustained attention task was correlated with good performance in the flexible attention task; i.e. animals with better vigilance exhibited greater behavioral flexibility. The findings are discussed in terms of potential neurobiological substrates, in particular noradrenergic mechanisms, that might underlie subject specific performance and subject specific responses to MPH. This article is part of a Special Issue entitled SI: Noradrenergic System. PMID:26688113

  13. Promoting Behavioral Regulation in Writing: Differential Effects on Indicators of Writing Performance and Learning Behaviors in 4th Graders with and without Externalizing Behavior

    Directory of Open Access Journals (Sweden)

    Cornelia Glaser

    2010-12-01

    Full Text Available In a writing intervention study with 4th-graders, we examined the effects of behaviour-oriented procedures (specification of behaviour rules and intentions; feedback on desired target behaviour, and self-evaluation of behaviour progress on the writing performance of students with aggressive and hyperactive behaviors. In two classes, 42 students, including 10 students with aggressive and hyperactive behaviors, were randomly assigned to one of two conditions: writing strategies program vs. writing strategies plus behaviour-regulation program. Both programs consisted of four 90-min sessions. In groups of nine to twelve students, all students received a cognitive strategies intervention for writing narratives (Glaser, 2005. At posttest and follow-up assessments (four weeks after the training, aggressive-hyperactive students who had been taught writing strategies in tandem with behaviour-regulation techniques outperformed students with problem behaviours who had not been taught such techniques in strategy-related and holistic measures of writing performance. Students with behaviour problems who had only received the writing strategies instruction gained least from attending the program.

  14. Differential genetic susceptibility to child risk at birth in predicting observed maternal behavior.

    Directory of Open Access Journals (Sweden)

    Keren Fortuna

    Full Text Available This study examined parenting as a function of child medical risks at birth and parental genotype (dopamine D4 receptor; DRD4. Our hypothesis was that the relation between child risks and later maternal sensitivity would depend on the presence/absence of a genetic variant in the mothers, thus revealing a gene by environment interaction (GXE. Risk at birth was defined by combining risk indices of children's gestational age at birth, birth weight, and admission to the neonatal intensive care unit. The DRD4-III 7-repeat allele was chosen as a relevant genotype as it was recently shown to moderate the effect of environmental stress on parental sensitivity. Mothers of 104 twin pairs provided DNA samples and were observed with their children in a laboratory play session when the children were 3.5 years old. Results indicate that higher levels of risk at birth were associated with less sensitive parenting only among mothers carrying the 7-repeat allele, but not among mothers carrying shorter alleles. Moreover, mothers who are carriers of the 7-repeat allele and whose children scored low on the risk index were observed to have the highest levels of sensitivity. These findings provide evidence for the interactive effects of genes and environment (in this study, children born at higher risk on parenting, and are consistent with a genetic differential susceptibility model of parenting by demonstrating that some parents are inherently more susceptible to environmental influences, both good and bad, than are others.

  15. Fracture Mechanisms in Steel Castings

    Directory of Open Access Journals (Sweden)

    Z. Stradomski

    2013-07-01

    Full Text Available The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.

  16. Differential contributions of serotonin receptors to the behavioral effects of indoleamine hallucinogens in mice.

    Science.gov (United States)

    Halberstadt, Adam L; Koedood, Liselore; Powell, Susan B; Geyer, Mark A

    2011-11-01

    Psilocin (4-hydroxy-N,N-dimethyltryptamine) is a hallucinogen that acts as an agonist at 5-HT(1A), 5-HT(2A), and 5-HT(2C) receptors. Psilocin is the active metabolite of psilocybin, a hallucinogen that is currently being investigated clinically as a potential therapeutic agent. In the present investigation, we used a combination of genetic and pharmacological approaches to identify the serotonin (5-HT) receptor subtypes responsible for mediating the effects of psilocin on head twitch response (HTR) and the behavioral pattern monitor (BPM) in C57BL/6J mice. We also compared the effects of psilocin with those of the putative 5-HT(2C) receptor-selective agonist 1-methylpsilocin and the hallucinogen and non-selective serotonin receptor agonist 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT). Psilocin, 1-methylpsilocin, and 5-MeO-DMT induced the HTR, effects that were absent in mice lacking the 5-HT(2A) receptor gene. When tested in the BPM, psilocin decreased locomotor activity, holepoking, and time spent in the center of the chamber, effects that were blocked by the selective 5-HT(1A) antagonist WAY-100635 but were not altered by the selective 5-HT(2C) antagonist SB 242,084 or by 5-HT(2A) receptor gene deletion. 5-MeO-DMT produced similar effects when tested in the BPM, and the action of 5-MeO-DMT was significantly attenuated by WAY-100635. Psilocin and 5-MeO-DMT also decreased the linearity of locomotor paths, effects that were mediated by 5-HT(2C) and 5-HT(1A) receptors, respectively. In contrast to psilocin and 5-MeO-DMT, 1-methylpsilocin (0.6-9.6 mg/kg) was completely inactive in the BPM. These findings confirm that psilocin acts as an agonist at 5-HT(1A), 5-HT(2A), and 5-HT(2C) receptors in mice, whereas the behavioral effects of 1-methylpsilocin indicate that this compound is acting at 5-HT(2A) sites but is inactive at the 5-HT(1A) receptor. The fact that 1-methylpsilocin displays greater pharmacological selectivity than psilocin indicates that 1-methylpsilocin

  17. To branch out or stay focused? Affective shifts differentially predict organizational citizenship behavior and task performance.

    Science.gov (United States)

    Yang, Liu-Qin; Simon, Lauren S; Wang, Lei; Zheng, Xiaoming

    2016-06-01

    We draw from personality systems interaction (PSI) theory (Kuhl, 2000) and regulatory focus theory (Higgins, 1997) to examine how dynamic positive and negative affective processes interact to predict both task and contextual performance. Using a twice-daily diary design over the course of a 3-week period, results from multilevel regression analysis revealed that distinct patterns of change in positive and negative affect optimally predicted contextual and task performance among a sample of 71 employees at a medium-sized technology company. Specifically, within persons, increases (upshifts) in positive affect over the course of a workday better predicted the subsequent day's organizational citizenship behavior (OCB) when such increases were coupled with decreases (downshifts) in negative affect. The optimal pattern of change in positive and negative affect differed, however, in predicting task performance. That is, upshifts in positive affect over the course of the workday better predicted the subsequent day's task performance when such upshifts were accompanied by upshifts in negative affect. The contribution of our findings to PSI theory and the broader affective and motivation regulation literatures, along with practical implications, are discussed. (PsycINFO Database Record PMID:26882443

  18. High Temperature Corrosion of Fe-C-S Cast Irons in Oxidizing and Sulfidizing Atmospheres

    Institute of Scientific and Technical Information of China (English)

    Thuan-Dinh NGUYEN; Dong-Bok LEE

    2008-01-01

    The corrosion behavior of spheroidal graphite and flake graphite cast irons was studied in oxidizing and sulfidizing atmospheres between 600 and 800℃ for 50 h. The corrosion rate in the sulfidizing atmosphere was faster than that in air above 700℃, due to the formation of the Feo.975S sulfide. The corrosion rate of the spheroidal graphite cast iron was similar to that of the flake graphite cast iron.

  19. Differential effects of the ascorbyl and tocopheryl derivative on the methamphetamine-induced toxic behavior and toxicity

    International Nuclear Information System (INIS)

    A previous study showed that high doses of methamphetamine induce self-injurious behavior (SIB) in rodents. Furthermore, the combination of methamphetamine and morphine increased lethality in mice. We recently surmised that the rise in SIB and mortality induced by methamphetamine and/or morphine may be related to oxidative stress. The present study was designed to determine whether an antioxidant could inhibit SIB or mortality directly induced by methamphetamine and/or morphine. The SIB induced by 20 mg/kg of methamphetamine was abolished by the administration of Na L-ascorbyl-2-phosphate (APS: 300 mg/kg), but not Na DL-α-tocopheryl phosphate (TPNa: 200 mg/kg). In contrast, APS (300 mg/kg) and TPNa (200 mg/kg) each significantly attenuated the lethality induced by methamphetamine and morphine. The present study showed that the signal intensity of superoxide adduct was increased by 20 mg/kg of methamphetamine in the heart and lungs, and methamphetamine plus morphine tended to increase superoxide adduct in all of the tissues measured by ESR spin trap methods. Adduct signal induced in brain by methamphetamine administration increased in significance, but in mouse administrated methamphetamine plus morphine. There are differential effects of administration of methamphetamine and coadministration of methamphetamine plus morphine on adduct signal. These results suggest that APS and TPNa are effective for reducing methamphetamine-induced toxicity and/or toxicological behavior. While APS and TPNa each affected methamphetamine- and/or morphine-induced toxicology and/or toxicological behavior, indicating that both drugs have antioxidative effects, their effects differed

  20. Skeleton castings dynamic load resistance

    Directory of Open Access Journals (Sweden)

    M. Cholewa

    2013-06-01

    Full Text Available Purpose: The article is to show selected results of research in a field of new type of cast spatial composite reinforcements. This article shows skeleton casting case as a particular approach to continuous, spatial composite reinforcement.Design/methodology/approach: The research is concerning properties of cast spatial microlattice structures called skeleton castings. In this paper results of impact test of skeleton casting with octahedron elementary cell were shown. The selection of internal topology of skeleton casting was based on numerical simulations of stress distribution.Findings: The possibility of manufacturing of geometrically complex skeleton castings without use of advanced techniques was confirmed.Research limitations/implications: With use of computer tomography, analysis of deformation mechanisms was carried out. Different levels of impact energies were usedPractical implications: Spatial skeleton casting with octahedron elementary cell confirmed their usefulness as impact energy absorbers.Originality/value: The overall aim of presented research was to determine the mechanisms of skeleton castings deformation processes. Thanks to CT data next step will be to create accurate numerical model for further simulation and design optimization.

  1. Fish gut microbiota analysis differentiates physiology and behavior of invasive Asian carp and indigenous American fish

    Science.gov (United States)

    Ye, Lin; Amberg, Jon J.; Chapman, Duane C.; Gaikowski, Mark P.; Liu, Wen-Tso

    2014-01-01

    Gut microbiota of invasive Asian silver carp (SVCP) and indigenous planktivorous gizzard shad (GZSD) in Mississippi river basin were compared using 16S rRNA gene pyrosequencing. Analysis of more than 440 000 quality-filtered sequences obtained from the foregut and hindgut of GZSD and SVCP revealed high microbial diversity in these samples. GZSD hindgut (GZSD_H) samples (n=23) with >7000 operational taxonomy units (OTUs) exhibited the highest alpha-diversity indices followed by SVCP foregut (n=15), GZSD foregut (n=9) and SVCP hindgut (SVCP_H) (n=24). UniFrac distance-based non-metric multidimensional scaling (NMDS) analysis showed that the microbiota of GZSD_H and SVCP_H were clearly separated into two clusters: samples in the GZSD cluster were observed to vary by sampling location and samples in the SVCP cluster by sampling date. NMDS further revealed distinct microbial community between foregut to hindgut for individual GZSD and SVCP. Cyanobacteria, Proteobacteria, Actinobacteria and Bacteroidetes were detected as the predominant phyla regardless of fish or gut type. The high abundance of Cyanobacteria observed was possibly supported by their role as the fish’s major food source. Furthermore, unique and shared OTUs and OTUs in each gut type were identified, three OTUs from the order Bacteroidales, the genus Bacillariophyta and the genus Clostridium were found significantly more abundant in GZSD_H (14.9–22.8%) than in SVCP_H (0.13–4.1%) samples. These differences were presumably caused by the differences in the type of food sources including bacteria ingested, the gut morphology and digestion, and the physiological behavior between GZSD and SVCP.

  2. Fish gut microbiota analysis differentiates physiology and behavior of invasive Asian carp and indigenous American fish.

    Science.gov (United States)

    Ye, Lin; Amberg, Jon; Chapman, Duane; Gaikowski, Mark; Liu, Wen-Tso

    2014-03-01

    Gut microbiota of invasive Asian silver carp (SVCP) and indigenous planktivorous gizzard shad (GZSD) in Mississippi river basin were compared using 16S rRNA gene pyrosequencing. Analysis of more than 440 000 quality-filtered sequences obtained from the foregut and hindgut of GZSD and SVCP revealed high microbial diversity in these samples. GZSD hindgut (GZSD_H) samples (n=23) with >7000 operational taxonomy units (OTUs) exhibited the highest alpha-diversity indices followed by SVCP foregut (n=15), GZSD foregut (n=9) and SVCP hindgut (SVCP_H) (n=24). UniFrac distance-based non-metric multidimensional scaling (NMDS) analysis showed that the microbiota of GZSD_H and SVCP_H were clearly separated into two clusters: samples in the GZSD cluster were observed to vary by sampling location and samples in the SVCP cluster by sampling date. NMDS further revealed distinct microbial community between foregut to hindgut for individual GZSD and SVCP. Cyanobacteria, Proteobacteria, Actinobacteria and Bacteroidetes were detected as the predominant phyla regardless of fish or gut type. The high abundance of Cyanobacteria observed was possibly supported by their role as the fish's major food source. Furthermore, unique and shared OTUs and OTUs in each gut type were identified, three OTUs from the order Bacteroidales, the genus Bacillariophyta and the genus Clostridium were found significantly more abundant in GZSD_H (14.9-22.8%) than in SVCP_H (0.13-4.1%) samples. These differences were presumably caused by the differences in the type of food sources including bacteria ingested, the gut morphology and digestion, and the physiological behavior between GZSD and SVCP.

  3. The mechanisms underlying sexual differentiation of behavior and physiology in mammals and birds: relative contributions of sex steroids and sex chromosomes

    OpenAIRE

    FumihikoMaekawa; HirokoOhki-hamazaki

    2014-01-01

    From a classical viewpoint, sex-specific behavior and physiological functions as well as the brain structures of mammals such as rats and mice, have been thought to be influenced by perinatal sex steroids secreted by the gonads. Sex steroids have also been thought to affect the differentiation of the sex-typical behavior of a few members of the avian order Galliformes, including the Japanese quail and chickens, during their development in ovo. However, recent mammalian studies that focused on...

  4. COMPARING THE EFFECTS OF DIFFERENTIAL REINFORCEMENT OF OTHER BEHAVIOR AND RESPONSE-COST CONTINGENCIES ON TICS IN YOUTH WITH TOURETTE SYNDROME

    OpenAIRE

    Capriotti, Matthew R; Brandt, Bryan C.; Ricketts, Emily J.; Espil, Flint M.; Woods, Douglas W

    2012-01-01

    Tics are rapid, repetitive, stereotyped movements or vocalizations that arise from neurobiological dysfunction and are influenced by environmental factors. Although persons with tic disorders often experience aversive social reactions in response to tics, little is known about the behavioral effects of such consequences. Along several dimensions, the present study compared the effects of two treatments on tics: response cost (RC) and differential reinforcement of other behavior (DRO). Four ch...

  5. Dry sliding wear behavior of stir cast AA6061-T6/AlNp composite%搅拌铸造AA6061-T6/AlNp复合材料的干滑动磨损行为

    Institute of Scientific and Technical Information of China (English)

    B. ASHOK KUMAR; N. MURUGAN; I. DINAHARAN

    2014-01-01

    以 AA6061为基体、AlN 颗粒为增强体,采用搅拌铸造工艺得到 AA6061-T6/AlNp复合材料,研究了AA6061-T6/AlNp复合材料的干滑动磨损行为。开发回归模型来预测复合材料的磨损率。采用四因素、五水平的正交实验进行优化。实验因素包括滑动速度、滑动距离、荷载、增强体 AlN 颗粒的质量分数。采用 SYSTAT 12软件和统计工具,如方差分析(方差分析)和 t 实验,验证回归模型。结果表明,开发的回归模型可以有效预测复合材料的磨损率,置信度达95%。采用回归模型,并依据磨损表面形貌分析,预测实验因素对 AA6061-T6/AlNp复合材料磨损率的影响。回归模型预测结果表明,复合材料的磨损率随着增强体AlN质量分数的增加而降低,随着滑动速度、滑动距离、荷载的增加而增加。%The dry sliding wear behavior of AA6061 matrix composite reinforced with aluminium nitride particles (AlN) produced by stir casting process was investigated. A regression model was developed to predict the wear rate of the prepared composite. A four-factor, five-level central composite rotatable design matrix was used to minimize the number of experimental runs. The factors considered in this study were sliding velocity, sliding distance, normal load and mass fraction of AlN reinforcement in the matrix. The developed regression model was validated by statistical software SYSTAT 12 and statistical tools such as analysis of variance (ANOVA) and student’s t test. It was found that the developed regression model could be effectively used to predict the wear rate at 95% confidence level. The influence of these factors on wear rate of AA6061/AlNp composite was analyzed using the developed regression model and predicted trends were discussed with the aid of worn surface morphologies. The regression model indicated that the wear rate of cast AA6061/AlNp composite decreased with an increase in the mass fraction

  6. Properties of polylactide inks for solvent-cast printing of three-dimensional freeform microstructures.

    Science.gov (United States)

    Guo, Shuang-Zhuang; Heuzey, Marie-Claude; Therriault, Daniel

    2014-02-01

    Solvent-cast printing is a highly versatile microfabrication technique that can be used to construct various geometries such as filaments, towers, scaffolds, and freeform circular spirals by the robotic deposition of a polymer solution ink onto a moving stage. In this work, we have performed a comprehensive characterization of the solvent-cast printing process using polylactide (PLA) solutions by analyzing the flow behavior of the solutions, the solvent evaporation kinetics, and the effect of process-related parameters on the crystallization of the extruded filaments. Rotational rheometry at low to moderate shear rates showed a nearly Newtonian behavior of the PLA solutions, while capillary flow analysis based on process-related data indicated shear thinning at high shear rates. Solvent vaporization tests suggested that the internal diffusion of the solvent through the filaments controlled the solvent removal of the extrudates. Different kinds of three-dimensional (3D) structures including a layer-by-layer tower, nine-layer scaffold, and freeform spiral were fabricated, and a processing map was given to show the proper ranges of process-related parameters (i.e., polymer content, applied pressure, nozzle diameter, and robot velocity) for the different geometries. The results of differential scanning calorimetry revealed that slow solvent evaporation could increase the ability of PLA to complete its crystallization process during the filament drying stage. The method developed here offers a new perspective for manufacturing complex structures from polymer solutions and provides guidelines to optimize the various parameters for 3D geometry fabrication.

  7. Segregation in cast products

    Indian Academy of Sciences (India)

    A Ghosh

    2001-02-01

    Microsegregation gets eliminated significantly if subsequent hot working and/or annealing are done on cast products. Macrosegregation however persists, causing problems in quality, and hence, has to be attended to. Microsegregation is a consequence of rejection of solutes by the solid into the interdendritic liquid. Scheil’s equation is mostly employed. However, other equations have been proposed, which take into account diffusion in solid phase and/or incomplete mixing in liquid. Macrosegregation results from movements of microsegregated regions over macroscopic distances due to motion of liquid and free crystals. Motion of impure interdendritic liquid causes regions of positive macrosegregation, whereas purer solid crystals yield negative macrosegregation. Flow of interdendritic liquid is primarily natural convection due to thermal and solutal buoyancy, and partly forced convection due to suction by shrinkage cavity formation etc. The present paper briefly deals with fundamentals of the above and contains some recent studies as well. Experimental investigations in molten alloys do not allow visualization of the complex flow pattern as well as other phenomena, such as dendrite-tip detachment. Experiments with room temperature analogues, and mathematical modelling have supplemented these efforts. However, the complexity of the phenomena demands simplifying assumptions. The agreement with experimental data is mostly qualitative. The paper also briefly discusses centreline macrosegregation during continuous casting of steel, methods to avoid it, and the, importance of early columnar-to-equiaxed transition (CET) as well as the fundamentals of CET.

  8. Development of Refractories for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    TIAN Shouxin; JIN Congjin; YAO Jinfu; LI Zeya

    2004-01-01

    The paper introduces refractories for continuous casting, especially, refractories for continuous casting for clean steel in baosteel. Developing direction of refractories for continuous casting has been pointed out to satisfy the new metallurgical operating practice.

  9. Lost Foam Casting in China

    Institute of Scientific and Technical Information of China (English)

    YE Sheng-ping; WU Zhi-chao

    2006-01-01

    @@ 1. Lost Foam Casting Committee of Foundry Institution of Chinese Mechanical Engineering Society (FICMES) From the beginning of the 1990s, China entered a research and expansion climax in lost foam casting technology realm after the United States, Germany, and Japan etc.

  10. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2009-01-01

    @@ This book consists of five sections:Chapter 1 Introduction,Chapter 2 Grey Iron,Chapter 3 Ductile Iron,Chapter 4Vermicular Cast Iron,and Chapter 5 White Cast Iron. CHINA FOUNDRY publishs this book in several parts serially,starting from the first issue of 2009.

  11. The Severely Impaired Do Profit Most: Differential Effectiveness of a Parent Management Training for Children with Externalizing Behavior Problems in a Natural Setting

    Science.gov (United States)

    Hautmann, Christopher; Stein, Petra; Eichelberger, Ilka; Hanisch, Charlotte; Pluck, Julia; Walter, Daniel; Dopfner, Manfred

    2011-01-01

    We investigated the differential effectiveness of a parent management training program for children with externalizing problem behavior. The parent management training was tested using a within-subject control group design. 270 families with children aged 3-10 years were included and assessments were made at 3 months before treatment, immediately…

  12. Differential resistance and the importance of antibiotic production in Acromyrmex echinatior leaf-cutting ant castes towards the entomopathogenic fungus Aspergillus nomius

    DEFF Research Database (Denmark)

    Poulsen, Michael; Hughes, William Owen Hamar; Boomsma, Jacobus Jan

    2006-01-01

    Paired exocrine metapleural glands are present in almost all ants and produce compounds with antibiotic properties towards a variety of pathogenic fungi and bacteria. In Acromyrmex leaf-cutting ants, small workers have relatively large metapleural glands compared to large workers, and thus harbour...... approximately half the number of gland cells of large workers, despite being only one-fifteenth their body mass. Here we present results showing that when the two worker castes of A. echinatior are treated with spores of the pathogenic fungus Aspergillus nomius in doses that correspond to the difference...... in metapleural gland cell numbers they do not differ in survival. However, we also show, for the first time, that small workers survive significantly longer than large workers when both are challenged with a dose of spores that corresponds to their difference in body mass. Furthermore, the time until Aspergillus...

  13. Aging degradation of cast stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O.K.; Chung, H.M.

    1985-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast-duplex stainless steels under light-water reactor operating conditions. Data from room-temperature Charpy-impact tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 450/sup 0/C are presented and compared with results from other studies. Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or in reactor service have been characterized. The results indicate that at least two processes contribute to the low-temperature embrittleent of duplex stainless steels, viz., weakening of the ferrite/austenite phase boundary by carbide precipitation and embrittlement of ferrite matrix by the formation of additional phases such as G-phase, Type X, or the ..cap alpha..' phase. Carbide precipitation has a significant effect on the onset of embrittlement of CF-8 and -8M grades of stainless steels aged at 400 or 450/sup 0/C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 450/sup 0/C. 18 refs., 13 figs.

  14. Aging degradation of cast stainless steel

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast-duplex stainless steels under light-water reactor operating conditions. Data from room-temperature Charpy-impact tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 4500C are presented and compared with results from other studies. Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or in reactor service have been characterized. The results indicate that at least two processes contribute to the low-temperature embrittleent of duplex stainless steels, viz., weakening of the ferrite/austenite phase boundary by carbide precipitation and embrittlement of ferrite matrix by the formation of additional phases such as G-phase, Type X, or the α' phase. Carbide precipitation has a significant effect on the onset of embrittlement of CF-8 and -8M grades of stainless steels aged at 400 or 4500C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 4500C. 18 refs., 13 figs

  15. Thermal and structural behavior of dioctadecyldimethylammonium bromide dispersions studied by differential scanning calorimetry and X-ray scattering.

    Directory of Open Access Journals (Sweden)

    Eloi Feitosa

    Full Text Available Dioctadecyldimethylammonium bromide (DODAB is a double chain cationic lipid, which assembles as bilayer structures in aqueous solution. The precise structures formed depend on, e.g., lipid concentration and temperature. We here combine differential scanning calorimetry (DSC and X-ray scattering (SAXS and WAXS to investigate the thermal and structural behavior of up to 120 mM DODAB in water within the temperature range 1-70 °C. Below 1 mM, this system is dominated by unilamellar vesicles (ULVs. Between 1 and 65 mM, ULVs and multilamellar structures (MLSs co-exist, while above 65 mM, the MLSs are the preferred structure. Depending on temperature, DSC and X-ray data show that the vesicles can be either in the subgel (SG, gel, or liquid crystalline (LC state, while the MLSs (with lattice distance d = 36.7 Å consist of interdigitated lamellae in the SG state, and ULVs in the LC state (no Bragg peak. Critical temperatures related to the thermal transitions of these bilayer structures obtained in the heating and cooling modes are reported, together with the corresponding transition enthalpies.

  16. Behavioral, ecological and genetic differentiation in an open environment--a study of a mysid population in the Baltic Sea.

    Directory of Open Access Journals (Sweden)

    Martin Ogonowski

    Full Text Available Diel vertical migration (DVM is often assumed to encompass an entire population. However, bimodal nighttime vertical distributions have been observed in various taxa. Mysid shrimp populations also display this pattern with one group concentrated in the pelagia and the other near the bottom. This may indicate alternative migratory strategies, resembling the seasonal partial migrations seen in birds, fishes and amphibians, where only a subset of the population migrates. To assess the persistence of these alternative strategies, we analyzed the nitrogen and carbon stable isotope signatures (as proxies for diet, biochemical indices (as proxies for growth condition, and genetic population divergence in the Baltic mysid Mysis salemaai collected at night in the pelagia and close to the bottom. Stable isotope signatures were significantly different between migrants (pelagic samples and residents (benthic samples, indicating persistent diet differences, with pelagic mysids having a more uniform and carnivorous diet. Sequencing of the mitochondrial cytochrome subunit I (COI gene showed genetic differentiation attributable to geographic location but not between benthic and pelagic groups. Divergent migration strategies were however supported by significantly lower gene flow between benthic populations indicating that these groups have a lower predisposition for horizontal migrations compared to pelagic ones. Different migration strategies did not convey measurable growth benefits as pelagic and benthic mysids had similar growth condition indices. Thus, the combination of ecological, biochemical and genetic markers indicate that this partial migration may be a plastic behavioral trait that yields equal growth benefits.

  17. Influence of rare earth elements on solidification behavior of a high speed steel for roll using differential scanning calorimetry

    Institute of Scientific and Technical Information of China (English)

    WANG Mingjia; CHEN Lei; WANG Zixi; BAO Er

    2011-01-01

    The influence of rare earths (RE) on solidification behavior of a high speed steel for roll was investigated by using differential scanning calorimetry (DSC) in combination of microstructure analysis.It was found that the sequence of solidification was L→γ,L→γ+MC,L→γ+M2C,L→γ+M6C,respectively.The start temperature and the latent heat liberated by unit mass of L→γ and L→γ+MC increased with increase of RE addition,indicating that RE could trigger the crystallization of the primary γ and the MC carbide more effectively.The promoting effect of RE on the heterogeneous nucleation was believed to be an important cause of this effect.Grain refinement,discontinuous network of eutectic carbides and disperse and finer MC were observed in the samples with RE addition,moreover,RES could act as the heterogeneous nucleus of the MC.RE addition was favorable for stable M6C at the expense of the metastable M2C.

  18. Prenatal Hypoxia in Different Periods of Embryogenesis Differentially Affects Cell Migration, Neuronal Plasticity, and Rat Behavior in Postnatal Ontogenesis.

    Science.gov (United States)

    Vasilev, Dmitrii S; Dubrovskaya, Nadezhda M; Tumanova, Natalia L; Zhuravin, Igor A

    2016-01-01

    Long-term effects of prenatal hypoxia on embryonic days E14 or E18 on the number, type and localization of cortical neurons, density of labile synaptopodin-positive dendritic spines, and parietal cortex-dependent behavioral tasks were examined in the postnatal ontogenesis of rats. An injection of 5'ethynyl-2'deoxyuridine to pregnant rats was used to label neurons generated on E14 or E18 in the fetuses. In control rat pups a majority of cells labeled on E14 were localized in the lower cortical layers V-VI while the cells labeled on E18 were mainly found in the superficial cortical layers II-III. It was shown that hypoxia both on E14 and E18 results in disruption of neuroblast generation and migration but affects different cell populations. In rat pups subjected to hypoxia on E14, the total number of labeled cells in the parietal cortex was decreased while the number of labeled neurons scattered within the superficial cortical layers was increased. In rat pups subjected to hypoxia on E18, the total number of labeled cells in the parietal cortex was also decreased but the number of scattered labeled neurons was higher in the lower cortical layers. It can be suggested that prenatal hypoxia both on E14 and E18 causes a disruption in neuroblast migration but with a different outcome. Only in rats subjected to hypoxia on E14 did we observe a reduction in the total number of pyramidal cortical neurons and the density of labile synaptopodin-positive dendritic spines in the molecular cortical layer during the first month after birth which affected development of the cortical functions. As a result, rats subjected to hypoxia on E14, but not on E18, had impaired development of the whisker-placing reaction and reduced ability to learn reaching by a forepaw. The data obtained suggest that hypoxia on E14 in the period of generation of the cells, which later differentiate into the pyramidal cortical neurons of the V-VI layers and form cortical minicolumns, affects formation of

  19. Al - BASED CAST COMPOSITES

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Yadav

    2011-08-01

    Full Text Available The economy is very important feature nowadays in themarket. The researches are playing an important role inengineering field to increase the life of machine parts /components and decrease the cost. The compositematerials have the potential to replace widely used steeland aluminium due to their good characteristics withbetter performance. The Al-based composites have foundextensive applications in automobile industries andaerospace industries due to their increased stiffness,strength, thermal conductivity and wear resistanceproperties. A number of particulate phases have beenemployed in the Al-alloy matrix. The cast aluminiumceramicparticulate composites are finding applications inpistons, connecting rods, cylinder liner, engine cylinderblock, electrical contacts etc.The present investigation isbased on study of the effect of particulate phase on theSEM study, micro-hardness, elastic modulus, tensilestrength and the wear behaviour of Al-5 % SiC-7 % Fe,Al-10 % SiC-6 % Fe and Al-15 % SiC-5 % Fe composites.

  20. NUMERICAL MODELING OF HARDENING OF UNINTERRUPTEDLY-CASTED BRONZE CASTING

    Directory of Open Access Journals (Sweden)

    E. I. Marukovich

    2009-01-01

    Full Text Available The three-dimensional numerical model for calculation of thermal fields during solidification of continuously casted bronze casting is developed. Coefficients of heat transfer on borders of calculation areas on the basis of the solution of inverse heat transfer conduction problem are determined. The analysis of thermal fields, depending on loop variables of drawing and the sizes of not cooled zone of crystallizer is curried out.

  1. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    Energy Technology Data Exchange (ETDEWEB)

    Thangirala, Mani

    2015-09-30

    The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynes 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which

  2. A Comparative Study on Wear Properties of As Cast, Cast Aged and Forge Aged A356 Alloy with Addition of Grain Refiner and/or Modifier

    Directory of Open Access Journals (Sweden)

    D.G. Mallapur

    2015-03-01

    Full Text Available In the present work, a comparative wear behavior study of three categories of materials viz, as cast, cast aged (casting followed by T6 and forge aged (forging followed by T6 has been investigated. Neither melt treatment nor solid state processing (like aging and forging seems to be altering the wear behavior of the materials drastically. Cast aged A356 materials exhibit higher wear resistance compared to as cast and forge aged A356 materials. Further, it was observed that cast aged samples register lower coefficient of friction compared to other samples. It is also noted that the difference in wear behavior is revealed only at conditions of higher load, higher speed and longer sliding distance of testing. At lower regimes the difference is marginal. Among cast aged samples, ones treated with combined addition exhibit better wear resistance compared to other materials. Samples treated with combined addition register lowest coefficient of friction followed by samples treated with Sr, those with B, those with Ti and untreated ones. Abrasive wear mechanism is found to be operative in the regime of higher loading and higher velocity of sliding. Adhesive wear mechanism seems to be dominating the wear process at the lower regime of load and velocity of sliding.

  3. Modelling of flow phenomena during DC casting

    NARCIS (Netherlands)

    Zuidema, J.

    2005-01-01

    Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an instanta

  4. Drosophila insulin-producing cells are differentially modulated by serotonin and octopamine receptors and affect social behavior.

    Directory of Open Access Journals (Sweden)

    Jiangnan Luo

    Full Text Available A set of 14 insulin-producing cells (IPCs in the Drosophila brain produces three insulin-like peptides (DILP2, 3 and 5. Activity in IPCs and release of DILPs is nutrient dependent and controlled by multiple factors such as fat body-derived proteins, neurotransmitters, and neuropeptides. Two monoamine receptors, the octopamine receptor OAMB and the serotonin receptor 5-HT1A, are expressed by the IPCs. These receptors may act antagonistically on adenylate cyclase. Here we investigate the action of the two receptors on activity in and output from the IPCs. Knockdown of OAMB by targeted RNAi led to elevated Dilp3 transcript levels in the brain, whereas 5-HT1A knockdown resulted in increases of Dilp2 and 5. OAMB-RNAi in IPCs leads to extended survival of starved flies and increased food intake, whereas 5-HT1A-RNAi produces the opposite phenotypes. However, knockdown of either OAMB or 5-HT1A in IPCs both lead to increased resistance to oxidative stress. In assays of carbohydrate levels we found that 5-HT1A knockdown in IPCs resulted in elevated hemolymph glucose, body glycogen and body trehalose levels, while no effects were seen after OAMB knockdown. We also found that manipulations of the two receptors in IPCs affected male aggressive behavior in different ways and 5-HT1A-RNAi reduced courtship latency. Our observations suggest that activation of 5-HT1A and OAMB signaling in IPCs generates differential effects on Dilp transcription, fly physiology, metabolism and social interactions. However the findings do not support an antagonistic action of the two monoamines and their receptors in this particular system.

  5. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang

    2009-01-01

    @@ Preface Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc.

  6. Niobium in gray cast iron

    International Nuclear Information System (INIS)

    The potential for utilization of niobium in gray cast iron is appraised and reviewed. Experiments described in literature indicate that niobium provides structural refinement of the eutectic cells and also promotes pearlite formation. (Author)

  7. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2011-01-01

    @@ Vermicular graphite cast iron(VG iron for short in the following sections)is a type of cast iron in which the graphite is intermediate in shape between flake and spheroidal.Compared with the normal flake graphite in grey iron, the graphite in VG iron is shorter and thicker and shows a curved, more rounded shape.Because its outer contour is exactly like a worm, hence it is called vermicular graphite.

  8. Light metal compound casting

    Institute of Scientific and Technical Information of China (English)

    Konrad; J.; M.; PAPIS; Joerg; F.; LOEFFLER; Peter; J.; UGGOWITZER

    2009-01-01

    ‘Compound casting’simplifies joining processes by directly casting a metallic melt onto a solid metal substrate. A continuously metallurgic transition is very important for industrial applications, such as joint structures of spaceframe constructions in transport industry. In this project, ‘compound casting’ of light metals is investigated, aiming at weight-saving. The substrate used is a wrought aluminium alloy of type AA5xxx, containing magnesium as main alloying element. The melts are aluminium alloys, containing various alloying elements (Cu, Si, Zn), and magnesium. By replacing the natural oxygen layer with a zinc layer, the inherent wetting difficulties were avoided, and compounds with flawless interfaces were successfully produced (no contraction defects, cracks or oxides). Electron microscopy and EDX investigations as well as optical micrographs of the interfacial areas revealed their continu- ously metallic constitution. Diffusion of alloying elements leads to heat-treatable microstructures in the vicinity of the joining interfaces in Al-Al couples. This permits significant variability of mechanical properties. Without significantly cutting down on wettability, the formation of low-melting intermetallic phases (Al3Mg2 and Al12Mg17 IMPs) at the interface of Al-Mg couples was avoided by applying a protective coating to the substrate.

  9. Virtualisation of casting engineering

    Directory of Open Access Journals (Sweden)

    J.S. Suchy

    2007-09-01

    Full Text Available Purpose: Fast response to an enquiry, minimization of costs of identification of best-suited process solution, as well as a capacity to tackle new challenges is the shortest description of the requirements posed by the contemporary market of machines and equipment. These, in consequence, called for making use of mathematical models and their solution by means of simulation algorithms.Design/methodology/approach: The notable effectiveness of numerical methods streamlined the production preparation process. Maintaining competitiveness, even more tough because of economic factors, is only possible due to cost-effective operation, high quality and well-timed order completion. These, on the other hand, can be facilitated by a broad application of IT tools aiding production management and preparation.Findings: Integration of systems aiding design processes, systems used for simulating selected elements of technologies, as well as of systems supporting instrumentation manufacturing calls for a need to solve a number of complex problems related to IT, mathematical modelling, logistics and knowledge management. Software packages for a simulation of processes that are indispensable in order to achieve the designed distribution of matter structures and condition are of particular importance.Research limitations/implications: Despite the fact that there is a wide range of software for these purposes available on the market, there is a need to build and integrate into IT systems new purpose-developed solutions customised to technologies applied and non-standard problems.Originality/value: Virtualization of casting engineering

  10. Electrochemical characterization of cast titanium alloys.

    Science.gov (United States)

    Cai, Zhuo; Shafer, Ty; Watanabe, Ikuya; Nunn, Martha E; Okabe, Toru

    2003-01-01

    A reaction layer forms on cast titanium alloy surfaces due to the reaction of the molten metal with the investment. This surface layer may affect the corrosion of the alloy in the oral environment. The objective of this study was to characterize the in vitro corrosion behavior of cast titanium alloys. ASTM Grade 2 CP titanium, Ti-6Al-4V, Ti-6Al-7Nb and Ti-13Nb-13Zr alloys were cast into a MgO-based investment. Experiments were performed on castings (N=4) with three surface conditions: (A) as-cast surface after sandblasting, (B) polished surface after removal of the reaction layer, and (C) sandblasted surface after removal of the reaction layer. Open-circuit potential (OCP) measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air+10% CO(2)) modified Tani-Zucchi synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was subsequently conducted in the same medium deaerated with N(2)+10% CO(2) gas 2 h before and during the experiment. Polarization resistance (R(P)) and corrosion rate (I(CORR)) were calculated. Numerical results were subjected to nonparametric statistical analysis at alpha=0.05. The OCP stabilized for all the specimens after 6 x 10(4)s. Apparent differences in anodic polarization were observed among the different surfaces for all the metals. A passivation region followed by breakdown and repassivation were seen on specimens with surfaces A and C. An extensive passive region was observed on all the metals with surface B. The Kruskal-Wallis test showed no significant differences in OCP, R(p), I(CORR) or break down potential for each of the three surfaces among all the metals. The Mann-Whitney test showed significantly lower R(P) and higher I(CORR) values for surface C compared to the other surfaces. Results indicate that the surface condition has more effect on corrosion of these alloys than the surface reaction layer. Within the oxidation potential range of the oral cavity, all the metal

  11. Inoculation of chromium white cast iron

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2009-01-01

    Full Text Available It has been proved that an addition of boron carbide introduced as an inoculant to the chromium white cast iron changes the structureof castings. Castings after inoculation revealed a different structure with numerous grains. Primary precipitates of chromium carbide also appeared, reducing the mechanical properties of as-cast parts. Properly established heat treatment regime makes chromium iron castings regain their, originally high, mechanical properties.

  12. Modelling of flow phenomena during DC casting

    OpenAIRE

    Zuidema, J.

    2005-01-01

    Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an instantaneous transformation, but occurs in temperature interval. In the casting process the latent heat is moved away by convection and conduction. A number of problems may occur during solidification, beca...

  13. Microstructural evolution and mechanical properties of as-cast and T6-treated AA2195 DC cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hekmat-Ardakan, A. [Universite de Sherbrook, Sherbrook, QC, Canada J1K 2R1 (Canada); Elgallad, E.M. [Universite du Quebec a Chicoutimi, Chicoutimi, QC, Canada G7H 2B1 (Canada); Ajersch, F. [Ecole Polytechnique de Montreal, Montreal, QC, Canada H3T 1J4 (Canada); Chen, X.-G., E-mail: xgrant_chen@uqac.ca [Universite du Quebec a Chicoutimi, Chicoutimi, QC, Canada G7H 2B1 (Canada)

    2012-12-15

    The use of direct chill (DC) cast ingot plates of AA2195 alloys has been recently extended for large mold applications in the plastics and automotive industries. The microstructural evolution of the as-cast AA2195 alloy was investigated using the Factsage thermodynamic software under both equilibrium and non-equilibrium conditions, and was compared with the results from differential scanning calorimetry (DSC) analysis and microstructural observations. The as-cast microstructure exhibited the presence of Al{sub 2}CuMg, Al{sub 2}Cu and Al{sub 2}CuLi intermetallic phases formed at the aluminum dendrite boundaries, which can be completely dissolved in the {alpha}-Al matrix during the solution treatment. A significant improvement in the mechanical properties of the AA2195 cast alloy after the T6 heat treatment is attributed to the formation of nano-scale {theta} Prime (Al{sub 2}Cu) and T1 (Al{sub 2}CuLi) precipitates. However, the non-uniform distribution of T1 precipitates together with the large size and low density indicate that the role of {theta} Prime precipitates in strengthening the AA2195 cast alloy is more dominant than that of the T1 precipitates, in contrast with the strengthening mechanism of the pre-deformed AA2195-T8 rolled products.

  14. Effect of heat treatment on the wear and corrosion behaviors of a gray cast iron coated with a COLMONOY 88 alloy deposited by high velocity oxygen fuel (HVOF) thermal spray

    OpenAIRE

    ÖZ, A.; R. Samur; Mindivan, H.; Demir, A.; S. Sagiroglu; A. K. Yakut

    2013-01-01

    The present work has been conducted in order to determine the influence of heat treatment on the wear and corrosion behaviours of a gray cast iron substrate coated with a Ni base coating deposited by HVOF thermal spray. The wear resistance of the coatings was obtained using a reciprocating wear tester by rubbing a 10 mm diameter steel ball on the coatings at normal atmospheric conditions. Corrosion tests were performed using potentiodynamic polarization measurements in a 3,5 % NaCl solution. ...

  15. THE FATIGUE CRACK PROPAGATION BEHAVIOR AND CRACK DEFLECTION OF A357 CASTING ALUMINUM ALLOYS%A357铸造铝合金疲劳裂纹扩展行为以及裂纹偏折

    Institute of Scientific and Technical Information of China (English)

    徐芳; 陈振中

    2011-01-01

    The fatigue crack propagation behavior of A357 casting aluminum alloys at stress ratios of 0.05 and 0.7 under T5 and T6 heat treatments were studied and crack propagation curves were modified by a crack deflection model. The research results show that the fatigue crack grows along the boundary of dendrite cells to cause a remarkable crack deflection. The fatigue crack propagation rate at r=0.05 is smaller than that at r=0.7 for both T5 and T6 heat treatments. The effect of heat treatment on the fatigue crack propagation rates cannot be seen. The fatigue crack propagation rates modified by the crack deflection model predict no change at r=0.7, while a remarkable increase of the fatigue crack propagation rates can be seen at r=0.05. It is more reasonable and accurate to use the effective stress intensity factors for Mode Ⅰand Ⅱ to describe the fatigue crack propagation rates when a crack deflection occurs.%该文研究了A357铸造铝合金在T5/T6两种热处理条件、应力比为0.05和0.7时的疲劳裂纹扩展行为,并用裂纹偏折模型对裂纹扩展速率曲线进行修正。研究结果表明,裂纹沿着树状晶边界扩展导致显著的裂纹偏折。在T5/T6两种热处理条件下,应力比r=0.05时的裂纹扩展速率均远小于应力比为0.7时的裂纹扩展速率,热处理方式对裂纹扩展速率没有影响。应力比r=0.7时,偏折裂纹模型修正后的裂纹扩展速率没有明显变化;而应力比r=0.05时,偏折裂纹模型修正后的裂纹扩展速率较修正前有显著增加。裂纹发生偏折时,采用同时考虑Ⅰ型和Ⅱ型裂纹的裂纹尖端有效应力强度因子描述裂纹扩展速率更合理也更准确。

  16. Copper base materials prepared by gel-casting process

    Institute of Scientific and Technical Information of China (English)

    LIU Weihua; JIA Chengchang; SHI Yantao; HAN Yuepeng

    2008-01-01

    Gel-casting process was developed as a new molding process in the field of copper base powder metallurgy to manufacture metal parts with excellent performance and complex shapes.Through changing the parameters of gel-casting process,such as dispersant and solid loading,the corresponding effects on the rheology of Cu slurries,molding and sintering behaviors were studied.The results show that the viscosity of Cu slurries was significantly reduced with an increase in dispersant.The most appropriate solid loading was found to be 61% and the sintering temperature was 910℃ in these experiments.After the optimization of parameters of gel-casting process,copper composite parts with relatively high density and better properties were obtained.

  17. Untouchable castes of Uttar Pradesh

    Directory of Open Access Journals (Sweden)

    Kharinin Artem Igorevich

    2015-04-01

    Full Text Available The Untouchable Castes of Uttar Pradesh are examined in this article. This region is one of the most populated in India. Also it is one of the most social mixed-composed in whole State. That’s why main conclusions which were made on this material can be extrapolated to all social space of country. The authors choose four ethno-caste groups, which represent the majority in untouchables and the three smallest in jaties. Their positions in regional hierarchy and economic specialization are analyzed in detail. There are a lot of information about their number, social structure, literacy rating, endogamy, day-to-day practices, customs and other features. Special accents were pointed on mind orientation of their elites toward integration in modern society or, conversely, toward the conservation of traditional forms of existence. The issues of origin and social evolution of untouchable castes of Uttar Pradesh are examined. There is assessment of castes’ sanskritization or other forms of social selfdevelopment. The quality of “scheduled” castes social environment is analyzed. As a marks of its positiveness the data about discrimination untouchables from other social groups and degree of political representativeness of “scheduled” castes, accessibility of education and labour were chosen. The conclusions were made about development degree of some castes. The factors that play role in positive changes in contemporary conditions were determined. The authors put forward their own hypothesis of future development of untouchable castes in Uttar Pradesh. Empiric base of this article was established on sources that have Indian origin and historical and social research of outstanding western indologies.

  18. Sensitivity analysis for casting process under stochastic modelling

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2015-09-01

    Full Text Available The present paper studies the reliability analysis of the casting process in foundry work using a probabilistic approach. As foundry industries in many developing countries suffer from poor quality of casting due to improper management, lack of resources and wrong working methods followed, which results in the decrement of productivity. Hence, to ensure the quality and productivity, favorable steps must be taken. The considered casting system has four main types of defects; namely mold shift, shrinkage, cold shut and blowholes. The complete casting system can fail due to the misalignment of the mold and combination of defects such as shrinkage and blow holes and can also fail by defects of shrinkage, blow holes and cold shut, simultaneously. The system is analyzed with the help of the supplementary variable technique and Laplace transformation. The availability, reliability, mean time to failure, sensitivity analysis and cost-effectiveness have been evaluated for the considered system. The results have been shown with the help of graphs, which predicts the behavior of the casting process system when any one of the defect or more than one defect appears.

  19. Development of vacuum die-casting process

    Institute of Scientific and Technical Information of China (English)

    Masashi Uchida

    2009-01-01

    The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great significance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting.

  20. Genome-wide and caste-specific DNA methylomes of the ants Camponotus floridanus and Harpegnathos saltator

    DEFF Research Database (Denmark)

    Bonasio, Roberto; Li, Qiye; Lian, Jinmin;

    2012-01-01

    methyltransferases and their genomes contain methylcytosine. To determine the relationship between DNA methylation and phenotypic plasticity in ants, we obtained and compared the genome-wide methylomes of different castes and developmental stages of Camponotus floridanus and Harpegnathos saltator.......Ant societies comprise individuals belonging to different castes characterized by specialized morphologies and behaviors. Because ant embryos can follow different developmental trajectories, epigenetic mechanisms must play a role in caste determination. Ants have a full set of DNA...

  1. Instant Casting Movie Theater: The Future Cast System

    Science.gov (United States)

    Maejima, Akinobu; Wemler, Shuhei; Machida, Tamotsu; Takebayashi, Masao; Morishima, Shigeo

    We have developed a visual entertainment system called “Future Cast” which enables anyone to easily participate in a pre-recorded or pre-created film as an instant CG movie star. This system provides audiences with the amazing opportunity to join the cast of a movie in real-time. The Future Cast System can automatically perform all the processes required to make this possible, from capturing participants' facial characteristics to rendering them into the movie. Our system can also be applied to any movie created using the same production process. We conducted our first experimental trial demonstration of the Future Cast System at the Mitsui-Toshiba pavilion at the 2005 World Exposition in Aichi Japan.

  2. As-Cast Acicular Ductile Aluminum Cast Iron

    Institute of Scientific and Technical Information of China (English)

    S M Mostafavi Kashani; S M A Boutorabi

    2009-01-01

    The effects of nickel (2.2%)and molybdenum (0.6%)additions on the kinetics, microstructure, and me-chanical properties of ductile aluminum cast iron were studied under the as-cast and tempered conditions. Test bars machined from cast to size samples were used for mechanical and metallurgical studies. The results showed that adding nickel and molybdenum to the base iron produced an upper bainitic structure, resulting in an increase in strength and hardness. The same trend was shown when the test bars were tempered at 300 ℃ in the range of 300℃ to 400 ℃. The elongation increased with increasing the temperature from 300 ℃ to 400 ℃. The carbon content of the retained austenite also increased with increasing the temperature. The results also showed that the kinetics, mi-crostructure, and mechanical properties of this iron were similar to those of Ni-Mo alloyed silicon ductile iron.

  3. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  4. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  5. Characterization of Acetone-Solution Casting Film of PMMA

    Institute of Scientific and Technical Information of China (English)

    Xue Feng; Fu Weiwen; Cheng Rongshi

    2006-01-01

    Acetone solution-casting films of poly(methylmethacrylate)were analyzed by differential scanning calorimetry and pyrolysis gas chromatography-mass spectroscopy under natural evaporation and ultrasonic vibration,respectively.Analytical results indicate that both the condensed structure of the polymer and the residue solvent in the films vary in different film-forming conditions and that the residuesolvated acetone in films prepared under natural evaporation is 12 times greater than that under ultrasonic vibration.

  6. Psychological and behavioral intervention improves the quality of life and mental health of patients suffering from differentiated thyroid cancer treated with postoperative radioactive iodine-131

    Directory of Open Access Journals (Sweden)

    Wu HX

    2016-05-01

    Full Text Available Hong-Xia Wu,1,* Hua Zhong,2,3,* Yue-Dong Xu,1 Cui-Ping Xu,4 Ying Zhang,5 Wei Zhang1 1Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, 2Department of Oncology, Shandong University of Traditional Chinese Medicine, 3Department of Traditional Chinese Medicine, Shandong Provincial Qianfoshan Hospital, Shandong University, 4Department of Nursing, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, 5Department of Nursing, Tianjin Chest Hospital, Tianjing, People’s Republic of China *These authors contributed equally to this work Background: We examined the effects of psychological and behavioral intervention on health-related quality of life and mental health among patients suffering from differentiated thyroid cancer (DTC treated with postoperative radioactive iodine-131 (RAI.Methods: Sixty patients with DTC, undergoing RAI, were randomly assigned to receive either conventional nursing (n=30 or a 1-year psychological and behavioral intervention based on conventional nursing (n=30. Health-related quality of life and mental health issues, depression, and anxiety were measured using the Quality of Life Core Questionnaire, Self-rating Depression Scale, and Self-rating Anxiety Score, respectively.Results: After RAI treatment, patients in both groups showed improved functional capacities (ie, physical, role, cognitive, emotional, and social and global quality of life, along with reduced depression and anxiety (P<0.05. At 1-year follow-up, compared with patients in the routine nursing group, those in the psychological and behavioral intervention group demonstrated greater improvements in functional capacities, global quality of life, and depression and anxiety symptoms (P<0.05.Conclusion: Psychological and behavioral interventions for patients with DTC undergoing RAI facilitated positive outcomes, suggesting that nursing care models that include psychological and behavioral interventions

  7. Research progress on squeeze casting in China

    Institute of Scientific and Technical Information of China (English)

    Li Yuanyuan; Zhang Weiwen; Zhao Haidong; You Dongdong; Zhang Datong; Shao Ming; Zhang Wen

    2014-01-01

    Squeeze casting is a technology with short route, high efficiency and precise forming, possessing features of casting and plastic processing. It is widely used to produce high performance metallic structural parts. As energy conservation and environmental protection concerns have risen, lightweight and high performance metal parts are urgently needed, which accelerated the development of squeeze casting technology over the past two decades in China. In this paper, research progress on squeeze casting aloys, typical parts manufacturing and development of squeeze casting equipment in China are introduced. The future trend and development priorities of squeeze casting are discussed.

  8. Dissimilarities in behavioral responses of snakes to roads and vehicles have implications for differential impacts across species

    OpenAIRE

    Andrews, Kimberly M.; Gibbons, J. Whitfield

    2005-01-01

    Roads can act as a barrier to overland movement of animals by causing habitat fragmentation, disrupting landscape permeability, and having an impact on survivorship patterns and behavior. We conducted field experiments to determine how southeastern U.S. snake species with different behaviors and ecologies responded to roads. We attributed interspecific differences in how individual snakes responded to ecological and behavioral differences among the species tested. The probability that a snake...

  9. Environmental Context Differentially Affects Behavioral, Leukocyte, Cortisol and Interleukin-6 Responses to Low Doses of Endotoxin in the Rhesus Monkey

    OpenAIRE

    Willette, Auriel A.; Lubach, Gabriele R.; Coe, Christopher L.

    2007-01-01

    Bacterial infections and proinflammatory cytokines induce behavioral and physiological responses associated with withdrawal and sickness behavior. These effects in rodents are often exacerbated by stressful environmental contexts. To model this synergistic effect of arousal and stress, low doses of lipopolysaccharide (LPS), 4 or 40 ng/kg, were administered to rhesus monkeys in different environmental contexts. Activity, emotional and social behaviors, cortisol, interleukin-6 (IL-6), and perip...

  10. Research on the squeeze cast technology of the castings with large ratio of height to thickness

    Institute of Scientific and Technical Information of China (English)

    LI Chen-xi; SAN Jing-chao; XU Na; CAO Liang; BAI Yan-hua; LI Rong-de

    2005-01-01

    The squeeze cast technology is only applicable, at present, to the castings with a ratio of height to thickness less than 3.5. Researching the squeeze cast technology for castings with a large ratio of height to thickness will broaden the applicable range of the advanced casting technology. This paper describes a study of the temperature distribution during solidification for castings with a ratio of height to thickness of 7 by the methods of experiment and computer simulation. The shrinkage porosity distribution in the castings and the mechanical properties of the castings were also researched. The experimental and simulated results show that increasing squeeze force, or enhancing mold temperature,cannot reduce the shrinkage porosities in the castings. When castings solidify in a sequential manner and the squeeze force effectively acts on the surface of the liquid metal, the shrinkage porosities in the castings are eliminated and mechanical properties are clearly improved.

  11. CAST Physics Proposal to SPSC

    CERN Document Server

    CAST, Collaboration

    2011-01-01

    The CAST experiment has the potential to search for solar axions (dark matter particle candidates) or other particles with similar coupling. E.g., paraphtons (Hidden Sector), chameleons (dark energy), while considering the possibility whether CAST could be transformed to an antenna for relic axions with rest mass up to 0.1 to 1meV. While axion searches suggest detectors with lower background, paraphoton and chameleon searches require detectors with sub-keV threshold energy and the use of transparent windows in front of the Micromegas detectors, which cover 3 out of the 4 CAST magnet exits. Ongoing theoretical estimates and experimental investigations will define the priorities of the suggested 4 physics items of this proposal for the period 2012-2014.

  12. Effect of heat treatment on the wear and corrosion behaviors of a gray cast iron coated with a COLMONOY 88 alloy deposited by high velocity oxygen fuel (HVOF thermal spray

    Directory of Open Access Journals (Sweden)

    A. Öz

    2013-07-01

    Full Text Available The present work has been conducted in order to determine the influence of heat treatment on the wear and corrosion behaviours of a gray cast iron substrate coated with a Ni base coating deposited by HVOF thermal spray. The wear resistance of the coatings was obtained using a reciprocating wear tester by rubbing a 10 mm diameter steel ball on the coatings at normal atmospheric conditions. Corrosion tests were performed using potentiodynamic polarization measurements in a 3,5 % NaCl solution. It was observed that the corrosion and wear resistance of the coatings increased along with the reduction of porosity and roughness by the heat treatment.

  13. Thermal analysis of cast-resin dry-type transformers

    International Nuclear Information System (INIS)

    Highlights: → Temperature distribution of cast-resin transformers is modeled by two approaches. → A FEM-based model with empirical-analytical formula and a 3D CFD model are developed. → The simulation results are compared and verified with the experimental data. → The influences of different parameters on temperature distribution are investigated. -- Abstract: Non-flammable characteristic of dry-type cast-resin transformers make them suitable for residential and hospital usages. However, because of resin's property, thermal behavior of these transformers is undesirable, so it is important to analyze their thermal behavior. In this paper temperature distribution of cast-resin transformers is modeled by two different approaches. A FEM-based model which uses experimental-analytical formula for air-cooling vertical ducts and a 3D finite volume based CFD model which is established in the ANSYS CFX software. In order to evaluate and compare the models, the simulation results were compared with the experimental data measured from an 800 kVA transformer. Finally, the influences of some construction parameters and environmental conditions on temperature distribution of cast-resin transformers were discussed.

  14. The Role of Particles in Fatigue Crack Propagation of Aluminum Matrix Composites and Casting Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhenzhong CHEN; Ping HE; Liqing CHEN

    2007-01-01

    Fatigue crack propagation (FCP) behaviors were studied to understand the role of SiC particles in 10 wt pct SiCp/A2024 composites and Si particles in casting aluminum alloy A356. The results show that a few particles appeared on the fracture surfaces in SiCp/Al composites even at high AK region, which indicates that cracks propagated predominantly within the matrix avoiding SiC particles due to the high strength of the particles and the strong particle/matrix interface. In casting aluminum alloy, Si particle debonding was more prominent.Compared with SiCp/Al composite, the casting aluminum alloy exhibited lower FCP rates, but had a slight steeper slope in the Paris region. Crack deflection and branching were found to be more remarkable in the casting aluminum alloy than that in the SiCp/Al composites, which may be contributed to higher FCP resistance in casting aluminum alloy.

  15. Fractomechanical Properties of As-Cast and Austempered SG Cast Iron Between -40 °C and +20 °C

    Directory of Open Access Journals (Sweden)

    V.E. Fierro

    2002-06-01

    Full Text Available The spheroidal graphite (SG cast iron fractomechanical response varies with the test temperature and with the microstructure parameters. In the present paper, we analyze this variation performing fractomechanical tests in a temperature range from -40°C to +20°C, doing also Charpy and tensile tests for material characterization. The tests were carried out on as-cast samples and heat treated samples to obtain an ADI grade 1. In both cases, we studied samples taken from two well differentiated "Y" block sizes. The results obtained show that, for the chemical composition analyzed, both castings have a fractomechanical response decrease as the temperature diminishes. Besides, the block size enlargement produce a deterioration of the mechanical properties (the fracture toughness, mainly, for both castings.

  16. Now-casting Irish GDP

    OpenAIRE

    D'Agostino, Antonello; McQuinn, Kieran; O'Brien, Derry

    2008-01-01

    In this paper we present "now-casts" of Irish GDP using timely data from a panel data set of 41 different variables. The approach seeks to resolve two issues which commonly confront forecastors of GDP - how to parsimoniously avail of the many different series, which can potentially influence GDP and how to reconcile the within-quarterly release of many of these series with the quarterly estimates of GDP? The now-casts in this paper are generated by firstly, using dynamic factor analysis to ex...

  17. Cementite Solidification in Cast Iron

    Science.gov (United States)

    Coronado, J. J.; Sinatora, A.; Albertin, E.

    2014-06-01

    Two hypereutectic cast irons (5.01 pct Cr and 5.19 pct V) were cast and the polished surfaces of test pieces were deep-etched and analyzed via scanning electron microscopy. The results show that graphite lamellae intersect the cementite and a thin austenite film nucleates and grows on the cementite plates. For both compositions, graphite and cementite can coexist as equilibrium phases, with the former always nucleating and growing first. The eutectic carbides grow from the austenite dendrites in a direction perpendicular to the primary plates.

  18. Search for chameleons with CAST

    OpenAIRE

    Anastassopoulos, V.; Arik, M.; Aune, S.(IRFU, Centre d' Etudes Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France); Barth, K.; Belov, A.; Bräuninger, H.; Cantatore, G.; Carmona, J.M.; Cetin, S.A.; Christensen, F.; J. I. Collar; T. Dafni; Davenport, M.; K. Desch; Dermenev, A.

    2015-01-01

    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter ($\\\\beta_{\\\\rm m}$) and to photons ($\\\\beta_{\\\\gamma}$) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1$\\\\,$keV to 400$\\\\,$eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600$\\\\,$eV. Even t...

  19. Differential genetic regulation of motor activity and anxiety-related behaviors in mice using an automated home cage task

    NARCIS (Netherlands)

    Kas, Martien J H; de Mooij-van Malsen, Annetrude J G; Olivier, Berend; Spruijt, Berry M; van Ree, Jan M

    2008-01-01

    Traditional behavioral tests, such as the open field test, measure an animal's responsiveness to a novel environment. However, it is generally difficult to assess whether the behavioral response obtained from these tests relates to the expression level of motor activity and/or to avoidance of anxiog

  20. Differential Pathways to Violence and Self-Injurious Behavior: African American and White Girls in the Juvenile Justice System

    Science.gov (United States)

    Holsinger, Kristi; Holsinger, Alexander M.

    2005-01-01

    Since the early 1990s, research, largely from a feminist perspective, has been devoted to identifying the "gender-specific needs" of delinquent girls. This article explores racial differences between girls and how these differences may affect the commission of violent behavior and self-injurious behavior. Self-report data were collected from 163…

  1. Violent Behaviors in Drug Addiction: Differential Profiles of Drug-Addicted Patients with and without Violence Problems

    Science.gov (United States)

    Fernandez-Montalvo, Javier; Lopez-Goni, Jose J.; Arteaga, Alfonso

    2012-01-01

    This study explored the prevalence of violent behaviors in patients who are addicted to drugs. A sample of 252 addicted patients (203 male and 49 female) who sought outpatient treatment was assessed. Information on violent behaviors, sociodemographic factors, consumption factors (assessed by the European version of the Addiction Severity Index…

  2. Differential effects of magnetic field exposure from domestic power supply on loco motor and exploratory behavior of an adult rat

    International Nuclear Information System (INIS)

    In the present study, we have examined the low intense magnetic field exposed on adult rats to understand effect of several behavioral parameters. The rats are tested in the open field and spontaneous alternation task after either a single or chronic exposure to the magnetic field. We found that magnetic field exposure had no effect on locomotor behavior in the adult. However, the exploratory behavior of adult rats in the open field was significantly affected. Indeed, we found a consistent increase in behavior performance viz. exploration time and number of exploration events in rats exposed to magnetic field. Our results demonstrate behavioral changes after magnetic field exposure in adult subjects. This also suggests possible deleterious effects of magnetic field exposure in the brain. (author)

  3. WEAR-RESISTANCE OF CHROMIC CAST IRONS OF EUTECTIC COMPOSITION

    Directory of Open Access Journals (Sweden)

    K. E. Baranovskij

    2009-01-01

    Full Text Available Casting of wear-resistant chrome cast irons in combined molds and iron chills is studied. Application of these ways of casting results in blending of carbides and increasing of hardness of castings.

  4. The mechanisms underlying sexual differentiation of behavior and physiology in mammals and birds: relative contributions of sex steroids and sex chromosomes

    Directory of Open Access Journals (Sweden)

    Fumihiko eMaekawa

    2014-08-01

    Full Text Available From a classical viewpoint, sex-specific behavior and physiological functions as well as the brain structures of mammals such as rats and mice, have been thought to be influenced by perinatal sex steroids secreted by the gonads. Sex steroids have also been thought to affect the differentiation of the sex-typical behavior of a few members of the avian order Galliformes, including the Japanese quail and chickens, during their development in ovo. However, recent mammalian studies that focused on the artificial shuffling or knockout of the sex-determining gene, Sry, have revealed that sex chromosomal effects may be associated with particular types of sex-linked differences such as aggression levels, social interaction, and autoimmune diseases, independently of sex steroid-mediated effects. In addition, studies on naturally occurring, rare phenomena such as gynandromorphic birds and experimentally constructed chimeras in which the composition of sex chromosomes in the brain differs from that in the other parts of the body, indicated that sex chromosomes play certain direct roles in the sex-specific differentiation of the gonads and the brain. In this article, we review the relative contributions of sex steroids and sex chromosomes in the determination of brain functions related to sexual behavior and reproductive physiology in mammals and birds.

  5. Developing technological process of obtaining giality casts

    Directory of Open Access Journals (Sweden)

    A. Issagulov

    2014-10-01

    Full Text Available The article considers the process of manufacturing castings using sand-resin forms and alloying furnace. Were the optimal technological parameters of manufacturing shell molds for the manufacture of castings of heating equipment. Using the same upon receipt of castings by casting in shell molds furnace alloying and deoxidation of the metal will provide consumers with quality products and have a positive impact on the economy in general engineering.

  6. The heat treatment of Fermanal cast steel

    OpenAIRE

    F. Binczyk; A. Smoliński; J. Szymszal

    2007-01-01

    The study discloses the results of microstructural examinations, testing of magnetic properties and hardness measurements as cast and after heat treatment conducted on the Fermanal cast steel. A characteristic feature of this cast steel is its density lower by about 10% than the density of carbon cast steel [4]. It has been proved that the factor deciding about the composition of microstructure (fraction of ferrite and austenite) is the content of aluminium. The matrix totally austenitic is p...

  7. CONTINUOUSLY-CYCLIC CASTING OF HOLLOW CYLINDER SLUGS OF HIGH-CHROMIUM CAST IRON

    Directory of Open Access Journals (Sweden)

    E. I. Marukovich

    2009-01-01

    Full Text Available The analysis of castings formation is presented and the package of measures dircted on increase of stability of casting process is developed. Parametres of casting of hollow cylindrical billets by the method of directional solidification out of white high-chromium cast iron are defined.

  8. Evolution of Social Insect Polyphenism Facilitated by the Sex Differentiation Cascade

    DEFF Research Database (Denmark)

    Klein, Antonia; Schultner, Eva; Lowak, Helena;

    2016-01-01

    -specific expression across life stages in the ant Cardiocondyla obscurior. We hypothesize that genes in the sex differentiation cascade evolved perception of alternative input signals for caste differentiation (i.e. environmental or genetic cues), and that their inherent switch-like and epistatic behavior facilitated......The major transition to eusociality required the evolution of a switch to canalize development into either a reproductive or a helper, the nature of which is currently unknown. Following predictions from the 'theory of facilitated variation', we identify sex differentiation pathways as promising...... candidates because of their pre-adaptation to regulating development of complex phenotypes. We show that conserved core genes, including the juvenile hormone-sensitive master sex differentiation gene doublesex (dsx) and a krüppel homolog 2 (kr-h2) with putative regulatory function, exhibit both sex and morph...

  9. Inoculation Effects of Cast Iron

    Directory of Open Access Journals (Sweden)

    E. Fraś

    2012-12-01

    Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

  10. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2010-01-01

    @@ Spheroidal Graphite Cast Iron(Ⅳ) 3.7 Segregation of SG iron The non-uniform distribution of solute elements during solidification results in the micro segregation of SG iron.As for the redistribution of elements in the phases of the solidification structure,there is no intrinsic difference between SG iron and grey iron[132].

  11. Search for chameleons with CAST

    DEFF Research Database (Denmark)

    Anastassopoulos, V.; Arik, M.; Aune, S.;

    2015-01-01

    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm) and to photons (βΥ) via the Primako eect. By reducing the X-ray detection...

  12. Advanced Lost Foam Casting Technology

    Energy Technology Data Exchange (ETDEWEB)

    Charles E. Bates; Harry E. Littleton; Don Askeland; Taras Molibog; Jason Hopper; Ben Vatankhah

    2000-11-30

    This report describes the research done under the six tasks to improve the process and make it more functional in an industrial environment. Task 1: Pattern Pyrolysis Products and Pattern Properties Task 2: Coating Quality Control Task 3: Fill and Solidification Code Task 4: Alternate Pattern Materials Task 5: Casting Distortion Task 6: Technology Transfer

  13. Colour Metallography of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    Zhou Jiyang; Liu Jincheng

    2010-01-01

    @@ Spheroidal Graphite Cast Iron(Ⅲ) 3.6 Solidification morphology of SG iron Solidification morphology refers to the description of change,distribution and interrelationship of the solidification structures such as graphite spheroids,austenite,eutectic cells,etc.[99

  14. Cern Axion Solar Telescope (CAST)

    CERN Multimedia

    2002-01-01

    The CERN Solar Axion Telescope, CAST, aims to shed light on a 30-year-old riddle of particle physics by detecting axions originating from the 15 million degree plasma in the Sun 's core. Axions were proposed as an extension to the Standard Model of particle physics to explain why CP violation is observed in weak but not strong interactions.

  15. 14 CFR 23.621 - Casting factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 23.621 Section 23.621... Casting factors. (a) General. The factors, tests, and inspections specified in paragraphs (b) through (d... do not support structural loads. (b) Bearing stresses and surfaces. The casting factors specified...

  16. Chimerical categories: caste, race, and genetics.

    Science.gov (United States)

    Sabir, Sharjeel

    2003-12-01

    Is discrimination based on caste equivalent to racism? This paper explores the complex relationship between genetic, race and caste. It also discusses the debate over the exclusion of a discussion of caste-based discrimination at the 2001 World Conference against Racism, Racial Discrimination, Xenophobia and Related Intolerance held in Durban, South Africa. PMID:14768649

  17. Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

    Energy Technology Data Exchange (ETDEWEB)

    Thangirala, Mani

    2015-09-30

    The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynes 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which

  18. Variation in Oxytocin Receptor Density in the Nucleus Accumbens has Differential Effects on Affiliative Behaviors in Monogamous and Polygamous Voles

    OpenAIRE

    Ross, Heather E.; Freeman, Sara M.; Spiegel, Lauren L.; Ren, Xianghui; Terwilliger, Ernest F.; Young, Larry J.

    2009-01-01

    Oxytocin receptors in the nucleus accumbens have been implicated in the regulation of alloparental behavior and pair bond formation in the socially monogamous prairie vole. Oxytocin receptor density in the nucleus accumbens is positively correlated with alloparenting in juvenile and adult female prairie voles, and oxytocin receptor antagonist infused into the nucleus accumbens blocks this behavior. Furthermore, prairie voles have higher densities of oxytocin receptors in the accumbens than no...

  19. Understanding the Behavior of Systems Pharmacology Models Using Mathematical Analysis of Differential Equations: Prolactin Modeling as a Case Study.

    Science.gov (United States)

    Bakshi, S; de Lange, E C; van der Graaf, P H; Danhof, M; Peletier, L A

    2016-07-01

    In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase-planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor-pool model with positive feedback is used to demonstrate the power of mathematical analysis. This model is nonlinear and exhibits multiple steady states, the stability of which is analyzed. The analysis offers insight into model behavior and suggests useful parameter regions, which simulations alone could not.

  20. Understanding the Behavior of Systems Pharmacology Models Using Mathematical Analysis of Differential Equations: Prolactin Modeling as a Case Study

    Science.gov (United States)

    Bakshi, S; de Lange, EC; Danhof, M; Peletier, LA

    2016-01-01

    In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase‐planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor‐pool model with positive feedback is used to demonstrate the power of mathematical analysis. This model is nonlinear and exhibits multiple steady states, the stability of which is analyzed. The analysis offers insight into model behavior and suggests useful parameter regions, which simulations alone could not. PMID:27405001

  1. Understanding the Behavior of Systems Pharmacology Models Using Mathematical Analysis of Differential Equations: Prolactin Modeling as a Case Study.

    Science.gov (United States)

    Bakshi, S; de Lange, E C; van der Graaf, P H; Danhof, M; Peletier, L A

    2016-07-01

    In this tutorial, we introduce basic concepts in dynamical systems analysis, such as phase-planes, stability, and bifurcation theory, useful for dissecting the behavior of complex and nonlinear models. A precursor-pool model with positive feedback is used to demonstrate the power of mathematical analysis. This model is nonlinear and exhibits multiple steady states, the stability of which is analyzed. The analysis offers insight into model behavior and suggests useful parameter regions, which simulations alone could not. PMID:27405001

  2. Behavioral evidence for the differential regulation of p-p38 MAPK and p-NF-κB in rats with trigeminal neuropathic pain

    OpenAIRE

    Lee Min K; Han Seung R; Park Min K; Kim Min J; Bae Yong C; Kim Sung K; Park Jae S; Ahn Dong K

    2011-01-01

    Abstract Background We investigated the differential regulation of p-p38 MAPK or p-NF-κB in male Sprague-Dawley rats with inferior alveolar nerve injury resulting from mal-positioned dental implants. For this purpose, we characterized the temporal expression of p-p38 MAPK or p-NF-κB in the medullary dorsal horn and examined changes in nociceptive behavior after a blockade of p-p38 MAPK or p-NF-κB pathways in rats with trigeminal neuropathic pain. Results Under anesthesia, the left lower secon...

  3. Actin-associated protein palladin is required for migration behavior and differentiation potential of C2C12 myoblast cells

    International Nuclear Information System (INIS)

    Highlights: • Palladin is involved in myogenesis in vitro. • Palladin knockdown by siRNA increases myoblast proliferation, viability and differentiation. • Palladin knockdown decreases C2C12 myoblast migration ability. - Abstract: The actin-associated protein palladin has been shown to be involved in differentiation processes in non-muscle tissues. However, but its function in skeletal muscle has rarely been studied. Palladin plays important roles in the regulation of diverse actin-related signaling in a number of cell types. Since intact actin-cytoskeletal remodeling is necessary for myogenesis, in the present study, we pursue to investigate the role of actin-associated palladin in skeletal muscle differentiation. Palladin in C2C12 myoblasts is knocked-down using specific small interfering RNA (siRNA). The results show that down-regulation of palladin decreased migratory activity of mouse skeletal muscle C2C12 myoblasts. Furthermore, the depletion of palladin enhances C2C12 vitality and proliferation. Of note, the loss of palladin promotes C2C12 to express the myosin heavy chain, suggesting that palladin has a role in the modulation of C2C12 differentiation. It is thus proposed that palladin is required for normal C2C12 myogenesis in vitro

  4. Actin-associated protein palladin is required for migration behavior and differentiation potential of C2C12 myoblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ngoc Uyen Nhi; Liang, Vincent Roderick; Wang, Hao-Ven, E-mail: hvwang@mail.ncku.edu.tw

    2014-09-26

    Highlights: • Palladin is involved in myogenesis in vitro. • Palladin knockdown by siRNA increases myoblast proliferation, viability and differentiation. • Palladin knockdown decreases C2C12 myoblast migration ability. - Abstract: The actin-associated protein palladin has been shown to be involved in differentiation processes in non-muscle tissues. However, but its function in skeletal muscle has rarely been studied. Palladin plays important roles in the regulation of diverse actin-related signaling in a number of cell types. Since intact actin-cytoskeletal remodeling is necessary for myogenesis, in the present study, we pursue to investigate the role of actin-associated palladin in skeletal muscle differentiation. Palladin in C2C12 myoblasts is knocked-down using specific small interfering RNA (siRNA). The results show that down-regulation of palladin decreased migratory activity of mouse skeletal muscle C2C12 myoblasts. Furthermore, the depletion of palladin enhances C2C12 vitality and proliferation. Of note, the loss of palladin promotes C2C12 to express the myosin heavy chain, suggesting that palladin has a role in the modulation of C2C12 differentiation. It is thus proposed that palladin is required for normal C2C12 myogenesis in vitro.

  5. Differentiating Co-Occurring Behavior Problems in Children with ADHD: Patterns of Emotional Reactivity and Executive Functioning

    Science.gov (United States)

    Graziano, Paulo A.; McNamara, Joseph P.; Geffken, Gary R.; Reid, Adam M.

    2013-01-01

    Objective:This study examined whether "top-down" and "bottom-up" control processes can differentiate children with ADHD who exhibit co-occurring aggression and/or internalizing symptoms. Method: Participants included 74 children ("M" age = 10.7 years) with a "Diagnostic and Statistical Manual of Mental…

  6. Differential genetic regulation of motor activity and anxiety-related behaviors in mice using an automated home cage task.

    Science.gov (United States)

    Kas, Martien J H; de Mooij-van Malsen, Annetrude J G; Olivier, Berend; Spruijt, Berry M; van Ree, Jan M

    2008-08-01

    Traditional behavioral tests, such as the open field test, measure an animal's responsiveness to a novel environment. However, it is generally difficult to assess whether the behavioral response obtained from these tests relates to the expression level of motor activity and/or to avoidance of anxiogenic areas. Here, an automated home cage environment for mice was designed to obtain independent measures of motor activity levels and of sheltered feeding preference during three consecutive days. Chronic treatment with the anxiolytic drug chlordiazepoxide (5 and 10 mg/kg/day) in C57BL/6J mice reduced sheltered feeding preference without altering motor activity levels. Furthermore, two distinct chromosome substitution strains, derived from C57BL/6J (host strain) and A/J (donor strain) inbred strains, expressed either increased sheltering preference in females (chromosome 15) or reduced motor activity levels in females and males (chromosome 1) when compared to C57BL/6J. Longitudinal behavioral monitoring revealed that these phenotypic differences maintained after adaptation to the home cage. Thus, by using new automated behavioral phenotyping approaches, behavior can be dissociated into distinct behavioral domains (e.g., anxiety-related and motor activity domains) with different underlying genetic origin and pharmacological responsiveness.

  7. Copper isotope behavior during extreme magma differentiation and degassing: a case study on Laacher See phonolite tephra (East Eifel, Germany)

    Science.gov (United States)

    Huang, Jian; Liu, Sheng-Ao; Wörner, Gerhard; Yu, Huimin; Xiao, Yilin

    2016-09-01

    Copper (Cu) isotopic analyses were performed on a set of samples from the Laacher See tephra (LST) (Eifel, Germany) to investigate whether Cu isotopes are fractionated during extreme magma differentiation and degassing. The LST represents a continuous fractional crystallization series from parental basanite through mafic to highly differentiated phonolites. Samples analyzed here include phonolites of variable degrees of differentiation, phonolite-basanite hybrid rocks formed by mixing basanite and phonolite magmas, and basanite-derived mega-crystals (i.e., clinopyroxene, amphibole, phlogopite). In addition, we analyzed a series of mafic parental lavas from surrounding volcanic centers to constrain the Cu isotopic features of the Eifel mantle. Mafic phonolites show strong depletion in Cu compared to their parental basanites from ~50 to ~3 ppm, indicating sulfide fractionation during the basanite-to-phonolite differentiation. Mass balance calculations, based on the most Cu-rich hybrid rock (δ65Cu = -0.21 ‰, [Cu] = 46.2 ppm), show that the parental basanite magmas have δ65Cu of ca. -0.21 ‰, lighter than those of the mafic phonolites (~0.11 ‰). This suggests that sulfide fractionation preferentially removes the lighter Cu isotope (63Cu) in S-saturated magmas. By contrast, all phonolites have a limited range of Cu contents (1.1 to 4.0 ppm) with no systematic variations with S, suggesting that Cu is not controlled by sulfide fractionation during the evolution of mafic to highly differentiated phonolites. The identical δ65Cu values (0.11 ± 0.03 ‰, 2SD, n = 10) of the phonolites, irrespective of highly diverse composition and extents of differentiation, indicate that fractional crystallization of silicates (e.g., plagioclase, sanidine, amphibole, pyroxene, olivine), Fe-Ti-oxides and phosphate (e.g., apatite) generates insignificant Cu isotope fractionation. The lack of correlations between δ65Cu and volatile contents (e.g., S, Cl) in the LST sequence implies

  8. Temperature and Thermal Stress Distribution for Metal Mold in Squeeze Casting Process

    Institute of Scientific and Technical Information of China (English)

    K.H.Chang; G.C.Jang; C.H.Lee; S.H.Lee

    2008-01-01

    In the squeeze casting process, loaded high pressure (over approximately 100 MPa) and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics (temperature and thermal stress) of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermo- physical and mechanical properties of the steel mold.

  9. CastML – a language for description of casting products and processes

    OpenAIRE

    A. Stawowy; R. Wrona; A. Macioł

    2008-01-01

    This work presents CastML – an XML dialect for description of casting products and processes. CastML is extension of MatML which is an extensible markup language designed specifically for the exchange of materials information. The set of CastML tags allows to describe materials’ information as well as technological processes, engineering drawings, products classifications and products manufacturers. CastML is simple, understandable and flexible language which makes it attractive for the speci...

  10. Porosity Defect Remodeling and Tensile Analysis of Cast Steel

    OpenAIRE

    Linfeng Sun; Ridong Liao; Wei Lu; Sibo Fu

    2016-01-01

    Tensile properties on ASTM A216 WCB cast steel with centerline porosity defect were studied with radiographic mapping and finite element remodeling technique. Non-linear elastic and plastic behaviors dependent on porosity were mathematically described by relevant equation sets. According to the ASTM E8 tensile test standard, matrix and defect specimens were machined into two categories by two types of height. After applying radiographic inspection, defect morphologies were mapped to the mid-s...

  11. An optimization of injecting system in die casting

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    After many years of development, die casting technology of metallic materials has been matured. In this paper,the lower-support and its injecting system were created with commercial software. And then the simulation software FLOW3D was applied to study the flow behavior of the melt during injection filling process. Both temperature field and defect distribution were simulated. Based on these results, the better injecting system with two additional overflows was adopted.

  12. Mechanism of Oscillation Mark Formation in Continuous Casting of Steel

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new mechanism of oscillation mark formation has been suggested based on the deep investigation of meniscus behavior in continuous casting of steel. It's confirmed that the meniscus form is important to oscillation mark formation. The factors related to the formation of oscillation mark are discussed in detail. The longer the solid shell existed at the root of meniscus and the smaller the contact angle between meniscus and mold wall, the deeper the oscillation mark.

  13. Emissions of nitrous oxide from casts of tropical earthworms belonging to different ecological categories

    OpenAIRE

    Majeed, M. Z.; Miambi, E.; Barois, I.; Blanchart, Eric; Brauman, Alain

    2013-01-01

    While earthworms' feeding behavior has been shown to be a key driver of greenhouse gas like nitrous oxide (N2O) emissions for temperate species, this assessment remains to be demonstrated for tropical ones. This study constitutes a comparative assessment of the impact of different feeding strategies of tropical earthworms on their cast emissions of N2O and the characterization of microbial communities associated with these emission dynamics. N2O flux was determined in vitro from casts of 2 ep...

  14. Tissue, developmental, and caste-specific expression of odorant binding proteins in a eusocial insect, the red imported fire ant, Solenopsis invicta

    Science.gov (United States)

    Zhang, Wei; Wanchoo, Arun; Ortiz-Urquiza, Almudena; Xia, Yuxian; Keyhani, Nemat O.

    2016-01-01

    Insects interact with the surrounding environment via chemoreception, and in social insects such as ants, chemoreception functions to mediate diverse behaviors including food acquisition, self/non-self recognition, and intraspecific communication. The invasive red imported fire ant, Solenopsis invicta, has spread worldwide, displaying a remarkable environmental adaptability. Odorant binding proteins (OBPs) are chemical compound carriers, involved in diverse physiological processes including odor detection and chemical transport. S. invicta contains a highly divergent 17-member OBP gene family, that includes an ant-specific expansion and the social organization implicated Gp-9 (OBP3) gene. A systematic gene expression analysis of the SiOBP repertoire was performed across social caste (workers, male and female alates), tissues (antennae, head, thorax, and abdomen), and developmental stages (egg, larvae, and pupae), revealing that although SiOBPs were expressed in the antennae, the major regions of expression were in the head and thorax across all castes, and the abdomen in male and female alates. SiOBPs were very highly expressed in female alates and at somewhat lower levels in male alates and workers. SiOBPs were differentially expressed, with unique signatures in various castes and tissues, suggesting functionality of SiOBPs beyond olfaction Expression patterns of SiOBP subgroups also showed relationships with their evolutionary relatedness. PMID:27765943

  15. Role of thirst and visual barriers in the differential behavior displayed by streptozotocin-treated rats in the elevated plus-maze and the open field test.

    Science.gov (United States)

    Rebolledo-Solleiro, Daniela; Crespo-Ramírez, Minerva; Roldán-Roldán, Gabriel; Hiriart, Marcia; Pérez de la Mora, Miguel

    2013-08-15

    Conflicting results have been obtained by several groups when studying the effects of streptozotocin (STZ)-treated rats in the elevated plus-maze (EPM). Since thirst is a prominent feature in STZ-induced diabetic-like condition, we studied whether the walls of the closed arms of the EPM, by limiting the search for water in the environment, may contribute to the observed differential behavioral outcomes. The aim of this study was to ascertain whether visual barriers within the EPM have an influence on the behavior of STZ-treated rats in this test of anxiety. A striking similarity between STZ-treated (50 mg/kg, i.p., in two consecutive days) and water deprived rats (72 h) was found in exploratory behavior in the EPM, showing an anxiolytic-like profile. However the anxiolytic response of STZ-treated rats exposed to the EPM shifts into an anxiogenic profile when they are subsequently tested in the open-field test, which unlike the EPM is devoid of visual barriers. Likewise, water deprived rats (72 h) also showed an anxiogenic profile when they were exposed to the open-field test. Our results indicate that experimental outcomes based on EPM observations can be misleading when studying physiological or pathological conditions, e.g. diabetes, in which thirst may increase exploratory behavior.

  16. Process development of thin strip steel casting

    Energy Technology Data Exchange (ETDEWEB)

    Sussman, R.C.; Williams, R.S.

    1990-12-01

    An important new frontier is being opened in steel processing with the emergence of thin strip casting. Casting steel directly to thin strip has enormous benefits in energy savings by potentially eliminating the need for hot reduction in a hot strip mill. This has been the driving force for numerous current research efforts into the direct strip casting of steel. The US Department of Energy initiated a program to evaluate the development of thin strip casting in the steel industry. In earlier phases of this program, planar flow casting on an experimental caster was studied by a team of engineers from Westinghouse Electric corporation and Armco Inc. A subsequent research program was designed as a fundamental and developmental study of both planar and melt overflow casting processes. This study was arranged as several separate and distinct tasks which were often completed by different teams of researchers. An early task was to design and build a water model to study fluid flow through different designs of planar flow casting nozzles. Another important task was mathematically modeling of melt overflow casting process. A mathematical solidification model for the formation of the strip in the melt overflow process was written. A study of the material and conditioning of casting substrates was made on the small wheel caster using the melt overflow casting process. This report discusses work on the development of thin steel casting.

  17. Prediction of Part Distortion in Die Casting

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

  18. Gating of Permanent Molds for Aluminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of

  19. Differential behavioral outcomes of 3,4-methylenedioxymethamphetamine (MDMA-ecstasy in anxiety-like responses in mice

    Directory of Open Access Journals (Sweden)

    V. Ferraz-de-Paula

    2011-05-01

    Full Text Available Anxiolytic and anxiogenic-like behavioral outcomes have been reported for methylenedioxymethamphetamine (MDMA or ecstasy in rodents. In the present experiment, we attempted to identify behavioral, hormonal and neurochemical outcomes of MDMA treatment to clarify its effects on anxiety-related responses in 2-month-old Balb/c male mice (25-35 g; N = 7-10 mice/group. The behavioral tests used were open field, elevated plus maze, hole board, and defensive behavior against predator odor. Moreover, we also determined striatal dopamine and dopamine turnover, and serum corticosterone levels. MDMA was injected ip at 0.2, 1.0, 5.0, 8.0, 10, or 20 mg/kg. MDMA at 10 mg/kg induced the following significant (P < 0.05 effects: a a dose-dependent increase in the distance traveled and in the time spent moving in the open field; b decreased exploratory activity in the hole board as measured by number of head dips and time spent in head dipping; c increased number of open arm entries and increased time spent in open arm exploration in the elevated plus maze; d increased time spent away from an aversive stimulus and decreased number of risk assessments in an aversive odor chamber; e increased serum corticosterone levels, and f increased striatal dopamine level and turnover. Taken together, these data suggest an anxiogenic-like effect of acute MDMA treatment, despite the fact that behavioral anxiety expression was impaired in some of the behavioral tests used as a consequence of the motor stimulating effects of MDMA.

  20. How to solve complex problems in foundry plants - future of casting simulation -

    Science.gov (United States)

    Ohnaka, I.

    2015-06-01

    Although the computer simulation of casting has progressed dramatically over the last decades, there are still many challenges and problems. This paper discusses how to solve complex engineering problems in foundry plants and what we should do in the future, in particular, for casting simulation. First, problem solving procedures including application of computer simulation are demonstrated and various difficulties are pointed-out exemplifying mainly porosity defects in sand castings of spheroidal graphite cast irons. Next, looking back conventional scientific and engineering research to understand casting phenomena, challenges and problems are discussed from problem solving view point, followed by discussion on the issues we should challenge such as how to integrate huge amount of dispersed knowledge in various disciplines, differentiation of science-oriented and engineering-oriented models, professional ethics, how to handle fluctuating materials, initial and boundary conditions, error accumulation, simulation codes as black-box, etc. Finally some suggestions are made on how to challenge the issues such as promotion of research on the simulation based on the science- oriented model and publication of reliable data of casting phenomena in complicated-shaped castings including reconsideration of the evaluation system.

  1. Flow of Steel in Mold Region During Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-guo; ZHANG Wen-xiao; JIN Jun-ze; J. W. Evans

    2007-01-01

    The particle image velocimetry (PIV) technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840 mm×280 mm. Two types of solidified shells, i.e., the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows: (1) There are two large recirculations above and below the fluid jet in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. (2) The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. (3) The higher the casting speed, the higher are the jet stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

  2. Mechanisms and mechanics of porosity formation in ductile iron castings

    Directory of Open Access Journals (Sweden)

    M. Perzyk

    2007-12-01

    Full Text Available Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay’s mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.

  3. Quantitative comparison of caste differences in honeybee hemolymph.

    Science.gov (United States)

    Chan, Queenie W T; Howes, Charles G; Foster, Leonard J

    2006-12-01

    The honeybee, Apis mellifera, is an invaluable partner in agriculture around the world both for its production of honey and, more importantly, for its role in pollination. Honeybees are largely unexplored at the molecular level despite a long and distinguished career as a model organism for understanding social behavior. Like other eusocial insects, honeybees can be divided into several castes: the queen (fertile female), workers (sterile females), and drones (males). Each caste has different energetic and metabolic requirements, and each differs in its susceptibility to pathogens, many of which have evolved to take advantage of the close social network inside a colony. Hemolymph, arthropods' equivalent to blood, distributes nutrients throughout the bee, and the immune components contained within it form one of the primary lines of defense against invading microorganisms. In this study we have applied qualitative and quantitative proteomics to gain a better understanding of honeybee hemolymph and how it varies among the castes and during development. We found large differences in hemolymph protein composition, especially between larval and adult stage bees and between male and female castes but even between adult workers and queens. We also provide experimental evidence for the expression of several unannotated honeybee genes and for the detection of biomarkers of a viral infection. Our data provide an initial molecular picture of honeybee hemolymph, to a greater depth than previous studies in other insects, and will pave the way for future biochemical studies of innate immunity in this animal. PMID:16920818

  4. Differential modulation of lateral septal vasopressin receptor blockade in spatial learning, social recognition, and anxiety-related behaviors in rats

    OpenAIRE

    Everts, HGJ; Koolhaas, JM

    1999-01-01

    The role of lateral septal vasopressin (VP) in the modulation of spatial memory, social memory, and anxiety-related behavior was studied in adult, male Wistar rats. Animals were equipped with osmotic minipumps delivering the VP-antagonist d(CH2)5-D-Tyr(Et)VAVP (1 ng/0.5 mu l per h) bilaterally into the lateral septum (LS). Subsequently, all rats were subjected to four behavioral tests. First, animals were tested in a spatial learning paradigm (Morris water maze; 12 trials), followed by the so...

  5. From gene networks underlying sex determination and gonadal differentiation to the development of neural networks regulating sociosexual behavior

    OpenAIRE

    Crews, David; Lou, Wendy; Fleming, Alison; Ogawa, Sonoko

    2006-01-01

    Genes are not expressed in isolation any more than social behavior has meaning outside of society. Both are in dynamic flux with the immediate environment that the gene/individual finds itself, which in turn establishes the timing, pattern, and conditions of expression. This means that complex behaviors and their genetic underpinnings should be viewed as a cumulative process, or as the result of experiences up to that point in time and, at the same time, as setting the stage for what will fol...

  6. Genetic differentiation of hypothalamus parentally biased transcripts in populations of the house mouse implicate the Prader-Willi syndrome imprinted region as a possible source of behavioral divergence.

    Science.gov (United States)

    Lorenc, Anna; Linnenbrink, Miriam; Montero, Inka; Schilhabel, Markus B; Tautz, Diethard

    2014-12-01

    Parentally biased expression of transcripts (genomic imprinting) in adult tissues, including the brain, can influence and possibly drive the evolution of behavioral traits. We have previously found that paternally determined cues are involved in population-specific mate choice decisions between two populations of the Western house mouse (Mus musculus domesticus). Here, we ask whether this could be mediated by genomically imprinted transcripts that are subject to fast differentiation between these populations. We focus on three organs that are of special relevance for mate choice and behavior: The vomeronasal organ (VNO), the hypothalamus, and the liver. To first identify candidate transcripts at a genome-wide scale, we used reciprocal crosses between M. m. domesticus and M. m. musculus inbred strains and RNA sequencing of the respective tissues. Using a false discovery cutoff derived from mock reciprocal cross comparisons, we find a total of 66 imprinted transcripts, 13 of which have previously not been described as imprinted. The largest number of imprinted transcripts were found in the hypothalamus; fewer were found in the VNO, and the least were found in the liver. To assess molecular differentiation and imprinting in the wild-derived M. m. domesticus populations, we sequenced the RNA of the hypothalamus from individuals of these populations. This confirmed the presence of the above identified transcripts also in wild populations and allowed us to search for those that show a high genetic differentiation between these populations. Our results identify the Ube3a-Snrpn imprinted region on chromosome 7 as a region that encompasses the largest number of previously not described transcripts with paternal expression bias, several of which are at the same time highly differentiated. For four of these, we confirmed their imprinting status via single nucleotide polymorphism-specific pyrosequencing assays with RNA from reciprocal crosses. In addition, we find the

  7. Differential modulation of lateral septal vasopressin receptor blockade in spatial learning, social recognition, and anxiety-related behaviors in rats

    NARCIS (Netherlands)

    Everts, HGJ; Koolhaas, JM

    1999-01-01

    The role of lateral septal vasopressin (VP) in the modulation of spatial memory, social memory, and anxiety-related behavior was studied in adult, male Wistar rats. Animals were equipped with osmotic minipumps delivering the VP-antagonist d(CH2)5-D-Tyr(Et)VAVP (1 ng/0.5 mu l per h) bilaterally into

  8. Differentiated Effects of Sensory Activities as Abolishing Operations via Non-Contingent Reinforcement on Academic and Aberrant Behavior

    Science.gov (United States)

    Mancil, G. Richmond; Haydon, Todd; Boman, Marty

    2016-01-01

    The purpose of the study was to evaluate the effectiveness of sensory activities used as antecedent interventions on the percentage correct on academic tasks and rate of aberrant behavior in three elementary aged children with Autism Spectrum Disorders (ASD). Study activities were conducted in an after school program for children with ASD where…

  9. Recent developments of InteCAST software and its applications on special castings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    with the development of computer technology, foundry CAE technology has made rapid progress. Commercial software packages of casting process simulation, therefore, have become more and more practical. This paper introduces both the recent developments and some applications of InteCAST software, a commercial numerical simulation software package for foundry industry, with more than 120 customers all over the world. The function modules of InteCAST8.0 and some new techniques, such as uneven mesh technology for mold filling simulation and numerical mouse technology for data visualization, were introduced. Several applications on special castings such as investment casting, low pressure die casting, and high pressure die casting, were given. These applications showed that the software can help engineers to optimize casting process by forecasting casting defect.

  10. The influence of calcium on technological properties and micropurity of steel castings

    Directory of Open Access Journals (Sweden)

    J. Hampl

    2016-07-01

    Full Text Available The paper analyzes the technological parameters, micro-purity and mechanical properties of castings of steel alloyed with calcium. The effect of calcium on the steel was analyzed on samples taken in the process of casting heavy castings and ingots of the weight of ranging from 40 000 to 60 000 kg. Samples for the determination of the liquidus temperature and the solidus temperature of cast steels were analysed using differential thermal analysis (DTA. The production of low alloyed steel grades was performed on the EAF - ASEA-SKF facilities and the production of highalloyed steels on the EAF - ASEA-SKF - SS-VOD facilities. The purity calcium was added into the steel by the injection of a stuffed profile.

  11. Pressure rig for repetitive casting

    Science.gov (United States)

    Vasquez, Peter (Inventor); Hutto, William R. (Inventor); Philips, Albert R. (Inventor)

    1989-01-01

    The invention is a pressure rig for repetitive casting of metal. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

  12. Search for chameleons with CAST

    CERN Document Server

    Anastassopoulos, V; Aune, S; Barth, K; Belov, A; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Christensen, F; Collar, J I; Dafni, T; Davenport, M; Desch, K; Dermenev, A; Eleftheriadis, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Giomataris, I; Hailey, C; Haug, F; Hasinoff, M D; Hofmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakobsen, A; Jakovčić, K; Kaminski, J; Karuza, M; Kavuk, M; Krčmar, M; Krieger, C; Krüger, A; Lakić, B; Laurent, J M; Liolios, A; Ljubičić, A; Luzón, G; Neff, S; Ortega, I; Papaevangelou, T; Pivovarov, M J; Raffelt, G; Riege, H; Rosu, M; Ruz, J; Savvidis, I; Solanki, S K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K; Brax, P; Lavrentyev, I; Upadhye, A

    2015-01-01

    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter ($\\beta_{\\rm m}$) and to photons ($\\beta_{\\gamma}$) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1$\\,$keV to 400$\\,$eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600$\\,$eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of $\\beta_{\\gamma}\\!\\lesssim\\!10^{11}$ for $1<\\beta_{\\rm m}<10^6$.

  13. Search for chameleons with CAST

    Directory of Open Access Journals (Sweden)

    V. Anastassopoulos

    2015-10-01

    Full Text Available In this work we present a search for (solar chameleons with the CERN Axion Solar Telescope (CAST. This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm and to photons (βγ via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1 keV to 400 eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600 eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ≲1011 for 1<βm<106.

  14. Casting and Mechanized Titanium Restorations

    OpenAIRE

    Madrigal, A.; Lopez, I; Suarez, MJ; Salido, MP.

    2002-01-01

    INTRODUCTION: New materials and methods for clinical dentistry are continuously being introduced. There is a growing interest in the use of titanium as a restorative material for several reasons: its relatively low cost, favorable physical properties and biocompatibility. However, titanium is technically more difficult to handle than conventional metal alloys. There are two fabrication methods for titanium restorations: casting and mechanized (a combination of machine duplication and spark er...

  15. On Quadratic Differential Forms

    NARCIS (Netherlands)

    Willems, J.C.; Trentelman, H.L.

    1998-01-01

    This paper develops a theory around the notion of quadratic differential forms in the context of linear differential systems. In many applications, we need to not only understand the behavior of the system variables but also the behavior of certain functionals of these variables. The obvious cases w

  16. Effect of cast steel production metallurgy on the emergence of casting defects

    Directory of Open Access Journals (Sweden)

    L. Čamek

    2016-10-01

    Full Text Available The paper documents metallurgical possibilities of high alloy cast steel production in open induction medium frequency furnaces and an electric arc furnace in a gravity die casting foundry. The observation was focused on the emergence of gas defects in steel castings. The content of gases achieved during the metallurgical processes was evaluated for every unit of the production equipment and the casting ladle before casting into disposable sand moulds. The sand mould area was considered to be constant. The aim was to evaluate the current metallurgical possibilities of affecting the content of gases in high alloy cast steel in the current technical conditions of the foundry.

  17. Computer precision simulation for titanium casting centrifugal mold filling of prescision titanium castings

    Directory of Open Access Journals (Sweden)

    Daming XU

    2004-08-01

    Full Text Available Computer simulation codes were developed based on proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings. Sample simulations were implemented for mold filling processes of precision titanium castings under gravity and different centrifugal casting techniques. The computation results show that the alloy melt has a much stronger mold filling ability for thin section castings unde a centrifugal force field than that only under the gravity. A "return back" mold filling manner is showed to be a reasonable technique for centrifugal casting processes, especially for thin section prcision castings.

  18. Strongly directional and differential swimming behavior of an adult female white shark, Carcharodon carcharias (Chondrichthyes: Lamnidae from Guadalupe Island, Mexico

    Directory of Open Access Journals (Sweden)

    Ramón Bonfil

    2015-03-01

    Full Text Available We report on an adult female white shark tracked for 288 days and 7,100 km in the NE Pacific Ocean. The shark, tagged with a real-time satellite tag off Guadalupe Island, Mexico in October 2006, remained around the island for 3.5 months but left in early February 2007 for a ca. 3,900 km westward migration. Heading and swimming speed data showed that: a the arc-like route followed by this shark during oceanic travel involved strongly directional rapid movement, and b once the shark arrived to a specific (ca. 680 km wide area located 790 km north-northeast of the Hawaiian Islands, it switched into a distinct roaming behavior. The shark remained in this roaming area from late March to at least late July 2007. We show that real-time satellite tags can provide unique and valuable information about the migratory behavior of white sharks.

  19. Differential typology and prognosis for dissexual behavior--a follow-up study of previously expert-appraised child molesters.

    Science.gov (United States)

    Beier, K M

    1998-01-01

    In terms of identifying socially-dysfunctional forms of sexuality--regardless of the legal valuation--dissexuality is defined as "an expression of social failure in sexual behavior." This failure was the subject of a longitudinal analysis of 186 expert-appraised pedophile sexual delinquents at the University of Kiel from 1945 through 1981. Of the child molesters 121 were followed up between September 1990 and September 1992 and 100 were personally contacted. The goal was to empirically develop prognosis criteria, given knowledge of the former delinquents' social development as well as sexual/dissexual practices, which could be of both forensic and interdisciplinary use. Among the bi- and homosexually-orientated pedophiles, the number of offenders for which the act is one of "compensation" was half of the initial collective. In contrast, this number was three-quarters for the heterosexually-orientated perpetrators. Correspondingly, the other half of the bi- and homosexually-orientated pedophiles were either exclusive-type or non-exclusive-type pedophiles (the so-called "true" pedophiles). Among the heterosexually-orientated offenders, the number was only one-quarter. According to the empirical data, we may expect a biographically continuing potential of dissexual behavior for only the exclusive and the non-exclusive type of pedophilia. Most of the relapsed dissexual activities showed up a long time after the expert's report. This is true for both the heterosexually- and the bi- and homosexually orientated groups. The present evaluation of the results allows assignment of behavior for certain delinquent typologies restricted to life phases or lifelong dissexual behavior. PMID:9587795

  20. Differential effects of photoperiod length on depression- and anxiety-like behavior in female and male diurnal spiny mice.

    Science.gov (United States)

    Ben-Hamo, Miriam; Tal, Katy; Paz-Cohen, Rotem; Kronfeld-Schor, Noga; Einat, Haim

    2016-10-15

    The relationships between biological rhythms and affective disorders are known but their underlying biology not clear. There is difficulty in studying circadian rhythms in humans and appropriate animal models are hard to identify or develop. Some studies show that diurnal rodents can be advantageous model animals for the study of interactions between biological rhythms and affective disorders but previous studies did not include females whereas in humans there are sex differences in affective disorders. The present study tested the effects of short photoperiods in both males and females of the diurnal golden spiny mouse (Acomys russatus). Adult, female and male spiny mice were housed in either neutral photoperiod (12:12 light/dark; NP), or short photoperiod (5:19 light/dark; SP) conditions. After 3weeks acclimatization, animals were tested for spontaneous activity in an open field, elevated plus maze (EPM), sweet solution preference (SSP) and the forced swim test (FST). Both sexes responded to the SP, but while SP males showed increased anxiety-like behavior in the EPM and depression-like behavior in the FST, females showed increased activity, reduced anxiety-like behavior in the EPM, depression-like response in the SSP and no effect in the FST. Differences between sexes were previously demonstrated in behavioral tests that followed a variety of manipulations, and were usually explained in the context of sex hormones. Yet, the current results cannot be compared with previous data from diurnal rodents and further testing of females from other diurnal rodents are needed to explore whether these differences are a general phenomenon or possibly unique to golden spiny mice. PMID:27343805

  1. Differential typology and prognosis for dissexual behavior--a follow-up study of previously expert-appraised child molesters.

    Science.gov (United States)

    Beier, K M

    1998-01-01

    In terms of identifying socially-dysfunctional forms of sexuality--regardless of the legal valuation--dissexuality is defined as "an expression of social failure in sexual behavior." This failure was the subject of a longitudinal analysis of 186 expert-appraised pedophile sexual delinquents at the University of Kiel from 1945 through 1981. Of the child molesters 121 were followed up between September 1990 and September 1992 and 100 were personally contacted. The goal was to empirically develop prognosis criteria, given knowledge of the former delinquents' social development as well as sexual/dissexual practices, which could be of both forensic and interdisciplinary use. Among the bi- and homosexually-orientated pedophiles, the number of offenders for which the act is one of "compensation" was half of the initial collective. In contrast, this number was three-quarters for the heterosexually-orientated perpetrators. Correspondingly, the other half of the bi- and homosexually-orientated pedophiles were either exclusive-type or non-exclusive-type pedophiles (the so-called "true" pedophiles). Among the heterosexually-orientated offenders, the number was only one-quarter. According to the empirical data, we may expect a biographically continuing potential of dissexual behavior for only the exclusive and the non-exclusive type of pedophilia. Most of the relapsed dissexual activities showed up a long time after the expert's report. This is true for both the heterosexually- and the bi- and homosexually orientated groups. The present evaluation of the results allows assignment of behavior for certain delinquent typologies restricted to life phases or lifelong dissexual behavior.

  2. Prenatal loud music and noise: differential impact on physiological arousal, hippocampal synaptogenesis and spatial behavior in one day-old chicks.

    Science.gov (United States)

    Sanyal, Tania; Kumar, Vivek; Nag, Tapas Chandra; Jain, Suman; Sreenivas, Vishnu; Wadhwa, Shashi

    2013-01-01

    Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise) exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation.

  3. Prenatal loud music and noise: differential impact on physiological arousal, hippocampal synaptogenesis and spatial behavior in one day-old chicks.

    Directory of Open Access Journals (Sweden)

    Tania Sanyal

    Full Text Available Prenatal auditory stimulation in chicks with species-specific sound and music at 65 dB facilitates spatial orientation and learning and is associated with significant morphological and biochemical changes in the hippocampus and brainstem auditory nuclei. Increased noradrenaline level due to physiological arousal is suggested as a possible mediator for the observed beneficial effects following patterned and rhythmic sound exposure. However, studies regarding the effects of prenatal high decibel sound (110 dB; music and noise exposure on the plasma noradrenaline level, synaptic protein expression in the hippocampus and spatial behavior of neonatal chicks remained unexplored. Here, we report that high decibel music stimulation moderately increases plasma noradrenaline level and positively modulates spatial orientation, learning and memory of one day-old chicks. In contrast, noise at the same sound pressure level results in excessive increase of plasma noradrenaline level and impairs the spatial behavior. Further, to assess the changes at the molecular level, we have quantified the expression of functional synapse markers: synaptophysin and PSD-95 in the hippocampus. Compared to the controls, both proteins show significantly increased expressions in the music stimulated group but decrease in expressions in the noise group. We propose that the differential increase of plasma noradrenaline level and altered expression of synaptic proteins in the hippocampus are responsible for the observed behavioral consequences following prenatal 110 dB music and noise stimulation.

  4. Stress ratio effects in fatigue of lost foam cast aluminum alloy 356

    Science.gov (United States)

    Palmer, David E.

    Lost foam casting is a highly versatile metalcasting process that offers significant benefits in terms of design flexibility, energy consumption, and environmental impact. In the present work, the fatigue behavior of lost foam cast aluminum alloy 356, in conditions T6 and T7, was investigated, under both zero and non-zero mean stress conditions, with either as-cast or machined surface finish. Scanning electron microscopy was used to identify and measure the defect from which fatigue fracture initiated. Based on the results, the applicability of nine different fatigue mean stress equations was compared. The widely-used Goodman equation was found to be highly non-conservative, while the Stulen, Topper-Sandor, and Walker equations performed reasonably well. Each of these three equations includes a material-dependent term for stress ratio sensitivity. The stress ratio sensitivity was found to be affected by heat treatment, with the T6 condition having greater sensitivity than the T7 condition. The surface condition (as-cast vs. machined) did not significantly affect the stress ratio sensitivity. The fatigue life of as-cast specimens was found to be approximately 60--70% lower than that of machined specimens at the same equivalent stress. This reduction could not be attributed to pore size alone, and is suspected to be due to the greater concentration of pyrolysis products at the as-cast surface. Directions for future work, including improved testing methods and some possible methods of improving the properties of lost foam castings, are discussed.

  5. The effects of Cr, Co, Al, Mo and Ta on the cyclic oxidation behavior of a prototype cast Ni-base superalloy based on a 2(5) composite statistically designed experiment

    Science.gov (United States)

    Barrett, C. A.

    1984-01-01

    A series of cast Ni-base superalloys were systematically varied at selected levels of Co, Cr, Mo, Ta, and Al. The elemental levels varied were Mo, 0 to 4 percent; Cr, 6 to 18 percent; Co, 0 to 20 percent, Ta, 0 to 8 percent; and Al, 3.25 to 6.25 percent. The cyclic oxidation resistance was determined from specific weight change data as a function of time for 1 hr cycles in static air at 1100 C. The significant terms in decreasing order of their importance were Al, Ta, Cr2, Al-Cr, Cr-Co, Co2, Al-Mo, Cr-Mo, Al-Al, and Mo-Ta. The Al term alone accounted for close to 82 percent of the explained variability. The estimating equation showed that the Al level was the most important and should be at its 6.25 wt % maximum value. The Mo and Ta levels should also be at their maximum 4 and 8 wt % respectively. The cobalt composition should be as low as possible, i.e., 0 wt%. The Cr level optimum varies depending on the other 4 levels. The X-ray diffaction results indicate the most protective scales are alumina/aluminate spinel stabilizized with a tri-rutile oxide high in Ta and Mo.

  6. Thermal casting process for the preparation of membranes

    Science.gov (United States)

    Caneba, G.T.M.; Soong, D.S.

    1985-07-10

    Disclosed is a method for providing anisotropic polymer membrane from a binary polymer/solvent solution using a thermal inversion process. A homogeneous binary solution is cast onto a support and cooled in such a way as to provide a differential in cooling rate across the thickness of the resulting membrane sheet. Isotropic or anisotropic structures of selected porosities can be produced, depending on the initial concentration of polymer in the selected solvent and on the extent of the differential in cooling rate. This differential results in a corresponding gradation in pore size. The method may be modified to provide a working skin by applying a rapid, high-temperature pulse to redissolve a predetermined thickness of the membrane at one of its faces and then freezing the entire structure.

  7. Differential behavioral reinforcement effects of dopamine receptor agonists in the rat with bilateral lesion of the posterior ventral tegmental area.

    Science.gov (United States)

    Ouachikh, Omar; Dieb, Wisam; Durif, Franck; Hafidi, Aziz

    2013-09-01

    Dopamine dysregulation syndrome in Parkinson's disease has been attributed to dopamine replacement therapies and/or a lesion of the dopaminergic system. The dopaminergic neuronal loss targets the substantia nigra and the ventral tegmental area (VTA). We hypothesize that dopamine replacement therapy is responsible for the potential reinforcement effect in Parkinson's disease by acting on the neuronal reward circuitry. Therefore this study was designed to explore the potential motivational effect of dopamine replacement therapy in bilateral VTA-lesioned animals. The posterior (p)VTA, which project to the nucleus accumbens (NAc) constitutes the major dopamine neuronal circuitry implicated in addictive disorders. Using the conditioned place preference (CPP) behavioral paradigm, we investigated the motivational effects of dopamine receptor agonists, and cocaine in rat with a 6-OHDA bilateral lesion of the pVTA. Amongst the dopamine receptor agonists used in this study only the D2R and D3R agonists (bromocriptine, PD128907 and pramipexole), induced a significant CPP in pVTA-lesioned animals. Dopamine receptor agonists did not induce behavioral sensitization in sham animals. Moreover, confocal D2R immunostaining analysis showed a significant increase in the number of D2R per cell body in the NAc shell of pVTA lesioned rats compared to sham. This result correlated, for the first time, the dopamine receptor agonists effect with DR2 overexpression in the NAc shell of pVTA-lesioned rats. In addition, cocaine, which is known to increase dopamine release, induced behavioral sensitization in sham group but not in dopamine deprived group. Thus, the later result highlighted the importance of pVTA-NAc dopaminergic pathway in positive reinforcements. Altogether these data suggested that the implication of the dopamine replacement therapy in the appearance of dopamine dysregulation syndrome in Parkinson's disease is probably due to both neuronal degeneration in the posterior VTA and

  8. Differential expression of Arc in the mesocorticolimbic system is involved in drug and natural rewarding behavior in rats

    Institute of Scientific and Technical Information of China (English)

    Mu LI; Wen-jie LIU; Bin LU; Yu-hua WANG; Jing-gen LIU

    2013-01-01

    Aim:To investigate the different effects of heroin and milk in activating the corticostriatal system that plays a critical role in reward reinforcement learning.Methods:Male SD rats were trained daily for 15 d to self-administer heroin or milk tablets in a classic runway drug self-administration model.Immunohistochemical assay was used to quantify Arc protein expression in the medial prefrontal cortex (mPFC),the nucleus accumbens (NAc),the dorsomedial striatum (DMS) and the ventrolateral striatum (VLS) in response to chronic self-administration of heroin or milk tablets.NMDA receptor antagonist MK801 (0.1 mg/kg) or dopamine D1 receptor antagonist SCH23390 (0.03 mg/kg) were intravenously injected at the same time as heroin was infused intravenously.Results:Runway training with heroin resulted in robust enhancement of Arc expression in the mPFC,the NAc and the DMS on d 1,7,and 15,and in the VLS on d 1 and d 7.However,runway training with milk led to increased Arc expression in the mPFC,the NAc and the DMS only on d 7 and/or d 15 but not on d 1.Moreover,runway training with milk failed to induce increased Arc protein in the VLS.Both heroin-seeking behavior and Arc protein expression were blocked by MK801 or SCH23390 administration.Conclusion:The VLS is likely to be critically involved in drug-seeking behavior.The NMDA-and D1 receptor-dependent Arc expression is important in drug-seeking behavior.

  9. Advanced casting technologies for lightweight automotive applications

    Directory of Open Access Journals (Sweden)

    Alan A. Luo

    2010-11-01

    Full Text Available This paper provides an overview of alloy and process developments in aluminum and magnesium castings for lightweight automotive applications. Wear-resistant aluminum alloys, creep-resistant and high strength/ductility magnesium alloys have been developed for automotive applications. On the process front, vacuum-assisted die casting and high vacuum die casting technologies have been developed for high-integrity body and chassis applications. Thin-wall and hollow casting components are being produced by low-pressure die casting processes for structural applications. Overcasting technology is gaining traction and has enabled mixed material designs for automotive sub-systems such as engine cradles and instrument panel beams. Simulation tools developed to predict the interfacial interactions of the dissimilar components and the structural integrity of the overcast systems are being validated in the casting trials.

  10. Clean Cast Steel Technology, Phase IV

    Energy Technology Data Exchange (ETDEWEB)

    Charles E. Bates

    2003-02-24

    The objective of the Clean Cast Steel Technology Program was to improve casting product quality by removing or minimizing oxide defects and to allow the production of higher integrity castings for high speed machining lines. Previous research has concentrated on macro-inclusions that break, chip, or crack machine tool cutters and drills and cause immediate shutdown of the machining lines. The overall goal of the project is to reduce the amount of surface macro-inclusions and improve the machinability of steel castings. Macro-inclusions and improve the machinability of steel castings. Macro-inclusions have been identified by industrial sponsors as a major barrier to improving the quality and marketability of steel castings.

  11. Chilling Tendency and Chill of Cast Iron

    Institute of Scientific and Technical Information of China (English)

    E. Fra(s); M. Górny; W. Kapturkiewicz; H. López

    2008-01-01

    An analytical expression is presented for the susceptibility of liquid cast iron to solidify according tothe Fe-C-X metastable system (also known as the chilling tendency of cast iron, CT). The analysis incorpo-rates the nucleation and growth processes associated with the eutectic transformation. The CT is related tothe physicochemical state of the liquid, the eutectic cells in the flake graphite, and the number of nodules innodular cast iron. In particular, the CT can be related to the critical wall thickness, Scr, or the chill width, Wcr,in wedge shaped castings. Finally, this work serves as a guide for understanding the effect of technical fac-tors such as the melt chemistry, the spheroidizing and inoculation practice, and the holding time and tam-perature on the resultant CT and chill of the cast iron. Theoretical calculations of Scr and Wcr compare wellwith experimental data for flake graphite and nodular cast iron.

  12. Homogenity of Die Casting and Returning Material

    Directory of Open Access Journals (Sweden)

    J. Malik

    2012-04-01

    Full Text Available Homogeneity of die castings is influenced by wide range of technological parameters as piston velocity in filling chamber of die casting machine, filling time of mould cavity, temperature of cast alloy, temperature of the mould, temperature of filling chamber, surface pressure on alloy during mould filling, final pressure and others. Based on stated parameters it is clear, that main parameters of die casting are filling time of die mould cavity and velocity of the melt in the ingates. Filling time must ensure the complete filling of the mould cavity before solidification process can negatively influence it. Among technological parameters also belong the returning material, which ratio in charge must be constrained according to requirement on final homogeneity of die castings. With the ratio of returning material influenced are the mechanical properties of castings, inner homogeneity and chemical composition.

  13. Method for casting thin metal objects

    Energy Technology Data Exchange (ETDEWEB)

    Pehrson, Brandon P; Moore, Alan F

    2015-04-14

    Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

  14. Investigation on Structure and Properties of Brass Casting

    Institute of Scientific and Technical Information of China (English)

    M.M.Haque; A.A.Khan

    2008-01-01

    In this work, alpha (α) brass was poured in green sand mould and metallic chill mould at about 1050℃. Sand casting method and metallic chill casting method are representing the slow and fast cooling rates of the castings, respectively. The slow cooling rate in the sand mould produces larger grains, while the metallic chill mould produces smaller grains in the castings. As the grain size decreases, the strength of the cast brass increases; micro-porosity in the casting decreases and the tendency for the casting to fracture during solidification decreases. Thus, the faster cooling rate casting offers higher strength, density and hardness compared to the slow cooling rate casting.

  15. COOLING METHOD OF SILUMINA CASTINGS AK15M3 AT VERTICAL CENTRIFUGAL CASTING

    OpenAIRE

    V. Yu. Stecenko; K. N. Baranov; A. P. Gutev

    2013-01-01

    The way of cooling of castings from silumin AK15M3 is developed at the vertical centrifugal casting, enabling to receive bimetallic blanks with high-disperse eutectic and hypereutectic microstructures and minimal allowance for machining.

  16. COOLING METHOD OF SILUMINA CASTINGS AK15M3 AT VERTICAL CENTRIFUGAL CASTING

    Directory of Open Access Journals (Sweden)

    V. Yu. Stecenko

    2013-01-01

    Full Text Available The way of cooling of castings from silumin AK15M3 is developed at the vertical centrifugal casting, enabling to receive bimetallic blanks with high-disperse eutectic and hypereutectic microstructures and minimal allowance for machining.

  17. Influence of Technological Parameters of Furane Mixtures on Shrinkage Creation in Ductile Cast Iron Castings

    Directory of Open Access Journals (Sweden)

    Vasková I.

    2014-10-01

    Full Text Available Ductile cast iron (GS has noticed great development in last decades and its boom has no analogue in history humankind. Ductile iron has broaden the use of castings from cast iron into areas, which where exclusively domains for steel castings. Mainly by castings, which weight is very high, is the propensity to shrinkage creation even higher. Shrinkage creation influences mainly material, construction of casting, gating system and mould. Therefore, the main realized experiment was to ascertain the influence of technological parameters of furane mixture on shrinkage creation in castings from ductile iron. Together was poured 12 testing items in 3 moulds forto determine and compare the impact of various technological parameters forms the propensity for shrinkage in the casting of LGG.

  18. RESEARCH AND APPLICATION OF AS-CAST WEAR RESISTANCE HIGH CHROMIUM CAST IRON

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The influence of alloy elements, such as boron and silicon, on the microstructure and properties of as-cast high chromium cast iron is studied. The results show that boron and silicon have a great effect on the mechanical properties and the wear resistance. Through proper addition of boron and silicon, the properties of as-cast high chromium cast iron can be improved effectively. Through analyzing the distribution of elements by scanning electron microscope, it has been shown that the addition of boron and silicon lowers the mass fraction of chromium saturated in as-cast austenite, and makes it unstable and liable to be transformed into martensite. The as-cast high chromium cast iron with proper content of boron and silicon is suitable for the manufacture of lining for asphalt concrete mixer and its wear resistance is 14 times that of lining made of low alloy white cast iron.

  19. Caste and wealth inequality in India

    OpenAIRE

    Zacharias, Ajit; Vakulabharanam, Vamsi

    2009-01-01

    In this paper, we conduct the novel exercise of analyzing the relationship between overall wealth inequality and caste divisions in India using nationally representative surveys on household wealth conducted during 1991–92 and 2002–03. According to our findings, the groups in India that are generally considered disadvantaged (known as Scheduled Castes or Scheduled Tribes) have, as one would expect, substantially lower wealth than the "forward" caste groups, while the Other Backward Classes an...

  20. Application of Anand's constitutive model on twin roll casting process of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    HU Xiao-dong; JU Dong-ying

    2006-01-01

    Twin-roll thin strip casting process combines casting and hot rolling into a single process,in which thermal stress and thermal mechanical stress were involved. Considering the high temperature gradient,the existing of liquid and solid regions and rolling deformation,suitable constitutive model is the key to describe the process. Anand's model is a temperature-dependent,rate-dependent and unified of creep and plasticity model and the Jaumann derivative was employed in Anand's model which makes the constitutive model frame-indifferent or objective,therefore the highly nonlinearities behavior in the twin-roll casting process can be simulated. The parameters of the Anand's model were regressed based on the compression tests of AZ31 magnesium alloy. The simulation results reveal that the Anand's model can well describe the deformation characteristics of twin-roll casting process. Based on the simulation results,the form of evolution equations in Anand's model was discussed.

  1. Development and application of titanium alloy casting technology in China

    Institute of Scientific and Technical Information of China (English)

    NAN Hai; XIE Cheng-mu; ZHAO Jia-qi

    2005-01-01

    The development and research of titanium cast alloy and its casting technology, especially its application inaeronautical industry in China are presented. The technology of molding, melting and casting of titanium alloy, casting quality control are introduced. The existing problems and development trend in titanium alloy casting technology are also discussed.

  2. Friction Stir Processing of Cast Superalloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for...

  3. Friction Stir Processing of Cast Superalloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing...

  4. Vacuum-sealed casting process under pressure

    Institute of Scientific and Technical Information of China (English)

    LI Chen-xi; GUO Tai-ming; WU Chun-jing; WANG Hong

    2006-01-01

    A new casting method, the vacuum-sealed mold casting under pressure, has been developed, and thin wall iron castings with high precision and smooth surface have been produced successfully with this casting method. The experimental results show that the liquid iron has a very excellent filling ability because a high negative pressure is formed in the mold cavity during filling process. The vacuum-sealed mold under pressure has very high compressive strength greater than 650 kPa, which is 3-4 times as high as that of the molds produced by high-pressure molding process or vacuum-sealed molding process.

  5. Cast Process Simulation for the Rapid Tooling.

    Science.gov (United States)

    Zhang, Renji; Jiang, Rui; Liu, Yuan; Yan, Yongnian

    1997-03-01

    A major use for RP (Rapid Prototyping) now is in the foundry industry. It is so called RT (Rapid Tooling). Models are used as patterns for sand and plaster casting or used as sacrificial models in investment casting in the RT. In order to improve casting quality, a cast process simulation program for the RT has been made. This simulation depends on analysis of size accuracy parameters. The result could be came back into the CAD forming program. After that a new CAD data have been adopted in RT process. Then the RT technology could have sufficient accuracy in fabrication. Work supported by the Natural Science Foundation of China (NSFC).

  6. Computer precision simulation for titanium casting centrifugal mold filling of prescision titanium castings

    OpenAIRE

    Xu, Daming; LI, XIN; Geving AN

    2004-01-01

    Computer simulation codes were developed based on proposed mathematical model for centrifugal mold filling processes and previous computer software for 3D mold filling and solidification of castings. Sample simulations were implemented for mold filling processes of precision titanium castings under gravity and different centrifugal casting techniques. The computation results show that the alloy melt has a much stronger mold filling ability for thin section castings unde a centrifugal force fi...

  7. Spray casting project final report

    International Nuclear Information System (INIS)

    Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step

  8. Arginine in α-defensins: differential effects on bactericidal activity correspond to geometry of membrane curvature generation and peptide-lipid phase behavior.

    Science.gov (United States)

    Schmidt, Nathan W; Tai, Kenneth P; Kamdar, Karishma; Mishra, Abhijit; Lai, Ghee Hwee; Zhao, Kun; Ouellette, André J; Wong, Gerard C L

    2012-06-22

    The conserved tridisulfide array of the α-defensin family imposes a common triple-stranded β-sheet topology on peptides that may have highly diverse primary structures, resulting in differential outcomes after targeted mutagenesis. In mouse cryptdin-4 (Crp4) and rhesus myeloid α-defensin-4 (RMAD4), complete substitutions of Arg with Lys affect bactericidal peptide activity very differently. Lys-for-Arg mutagenesis attenuates Crp4, but RMAD4 activity remains mostly unchanged. Here, we show that the differential biological effect of Lys-for-Arg replacements can be understood by the distinct phase behavior of the experimental peptide-lipid system. In Crp4, small-angle x-ray scattering analyses showed that Arg-to-Lys replacements shifted the induced nanoporous phases to a different range of lipid compositions compared with the Arg-rich native peptide, consistent with the attenuation of bactericidal activity by Lys-for-Arg mutations. In contrast, such phases generated by RMAD4 were largely unchanged. The concordance between small-angle x-ray scattering measurements and biological activity provides evidence that specific types of α-defensin-induced membrane curvature-generating tendencies correspond directly to bactericidal activity via membrane destabilization.

  9. Control of Cast Iron Microstructure

    Science.gov (United States)

    Graham, J.; Lillybeck, N.; Franco, N.; Stefanescu, D. M.

    1985-01-01

    The use of microgravity for industrial research in the processing of cast iron was investigated. Solidification experiments were conducted using the KC-135 and F-104 aircraft, and an experiment plan was developed for follow-on experiments using the Shuttle. Three areas of interest are identified: (1) measurement of thermophysical properties in the melt; (2) understanding of the relative roles of homogeneous nucleation, grain multiplication, and innocultants in forming the microstructure; and (3) exploring the possibility of obtaining an aligned graphite structure in hypereutectic Fe, Ni, and Co.

  10. The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2008-08-01

    Full Text Available The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

  11. Differential substrate specificity and kinetic behavior of Escherichia coli YfdW and Oxalobacter formigenes formyl coenzyme A transferase.

    Science.gov (United States)

    Toyota, Cory G; Berthold, Catrine L; Gruez, Arnaud; Jónsson, Stefán; Lindqvist, Ylva; Cambillau, Christian; Richards, Nigel G J

    2008-04-01

    The yfdXWUVE operon appears to encode proteins that enhance the ability of Escherichia coli MG1655 to survive under acidic conditions. Although the molecular mechanisms underlying this phenotypic behavior remain to be elucidated, findings from structural genomic studies have shown that the structure of YfdW, the protein encoded by the yfdW gene, is homologous to that of the enzyme that mediates oxalate catabolism in the obligate anaerobe Oxalobacter formigenes, O. formigenes formyl coenzyme A transferase (FRC). We now report the first detailed examination of the steady-state kinetic behavior and substrate specificity of recombinant, wild-type YfdW. Our studies confirm that YfdW is a formyl coenzyme A (formyl-CoA) transferase, and YfdW appears to be more stringent than the corresponding enzyme (FRC) in Oxalobacter in employing formyl-CoA and oxalate as substrates. We also report the effects of replacing Trp-48 in the FRC active site with the glutamine residue that occupies an equivalent position in the E. coli protein. The results of these experiments show that Trp-48 precludes oxalate binding to a site that mediates substrate inhibition for YfdW. In addition, the replacement of Trp-48 by Gln-48 yields an FRC variant for which oxalate-dependent substrate inhibition is modified to resemble that seen for YfdW. Our findings illustrate the utility of structural homology in assigning enzyme function and raise the question of whether oxalate catabolism takes place in E. coli upon the up-regulation of the yfdXWUVE operon under acidic conditions. PMID:18245280

  12. Differential Histopathological and Behavioral Outcomes Eight Weeks after Rat Spinal Cord Injury by Contusion, Dislocation, and Distraction Mechanisms

    Science.gov (United States)

    Chen, Kinon; Liu, Jie; Assinck, Peggy; Bhatnagar, Tim; Streijger, Femke; Zhu, Qingan; Dvorak, Marcel F.; Kwon, Brian K.; Tetzlaff, Wolfram

    2016-01-01

    Abstract The objective of this study was to compare the long-term histological and behavioral outcomes after spinal cord injury (SCI) induced by one of three distinct biomechanical mechanisms: dislocation, contusion, and distraction. Thirty male Sprague-Dawley rats were randomized to incur a traumatic cervical SCI by one of these three clinically relevant mechanisms. The injured cervical spines were surgically stabilized, and motor function was assessed for the following 8 weeks. The spinal cords were then harvested for histologic analysis. Quantification of white matter sparing using Luxol fast blue staining revealed that dislocation injury caused the greatest overall loss of white matter, both laterally and along the rostrocaudal axis of the injured cord. Distraction caused enlarged extracellular spaces and structural alteration in the white matter but spared the most myelinated axons overall. Contusion caused the most severe loss of myelinated axons in the dorsal white matter. Immunohistochemistry for the neuronal marker NeuN combined with Fluoro Nissl revealed that the dislocation mechanism resulted in the greatest neuronal cell losses in both the ventral and dorsal horns. After the distraction injury mechanism, animals displayed no recovery of grip strength over time, in contrast to the animals subjected to contusion or dislocation injuries. After the dislocation injury mechanism, animals displayed no improvement in the grooming test, in contrast to the animals subjected to contusion or distraction injuries. These data indicate that different SCI mechanisms result in distinct patterns of histopathology and behavioral recovery. Understanding this heterogeneity may be important for the future development of therapeutic interventions that target specific neuropathology after SCI. PMID:26671448

  13. Variable behavior of iPSCs derived from CML patients for response to TKI and hematopoietic differentiation.

    Directory of Open Access Journals (Sweden)

    Aurélie Bedel

    Full Text Available Chronic myeloid leukemia disease (CML found effective therapy by treating patients with tyrosine kinase inhibitors (TKI, which suppress the BCR-ABL1 oncogene activity. However, the majority of patients achieving remission with TKI still have molecular evidences of disease persistence. Various mechanisms have been proposed to explain the disease persistence and recurrence. One of the hypotheses is that the primitive leukemic stem cells (LSCs can survive in the presence of TKI. Understanding the mechanisms leading to TKI resistance of the LSCs in CML is a critical issue but is limited by availability of cells from patients. We generated induced pluripotent stem cells (iPSCs derived from CD34⁺ blood cells isolated from CML patients (CML-iPSCs as a model for studying LSCs survival in the presence of TKI and the mechanisms supporting TKI resistance. Interestingly, CML-iPSCs resisted to TKI treatment and their survival did not depend on BCR-ABL1, as for primitive LSCs. Induction of hematopoietic differentiation of CML-iPSC clones was reduced compared to normal clones. Hematopoietic progenitors obtained from iPSCs partially recovered TKI sensitivity. Notably, different CML-iPSCs obtained from the same CML patients were heterogeneous, in terms of BCR-ABL1 level and proliferation. Thus, several clones of CML-iPSCs are a powerful model to decipher all the mechanisms leading to LSC survival following TKI therapy and are a promising tool for testing new therapeutic agents.

  14. High strength aluminum cast alloy: A Sc modification of a standard Al–Si–Mg cast alloy

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Arfan, E-mail: engr.arfan@gmail.com [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Xu, Cong; Xuejiao, Wang [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Hanada, Shuji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamagata, Hiroshi [Center for Advanced Die Engineering and Technology, Gifu University, 1-1 Yanagido, Gifu City, Gifu 501-1193 (Japan); Hao, LiRong [Hebei Sitong New Metal Material Co., Ltd., Baoding 071105 (China); Chaoli, Ma [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China)

    2014-05-01

    A standard Aluminum–Silicon–Magnesium cast alloy (A357 foundry alloy without Beryllium) modified with different weight percentages of Scandium (Sc), has been studied to evaluate the effects of Sc contents on microstructure and strength. Study has been conducted under optimized parameters of melting, casting and heat treatment. Characterization techniques like optical microscopy, SEM, TEM and tensile testing were employed to analyze the microstructure and mechanical properties. Results obtained in this research indicate that with the increase of Sc contents up to 0.4 wt%, grain size is decreased by 80% while ultimate tensile strength and hardness are increased by 28% and 19% respectively. Moreover along with the increase in strength, elongation to failure is also increased up to 165%. This is quite interesting behavior because usually strength and ductility have inverse relationship.

  15. High strength aluminum cast alloy: A Sc modification of a standard Al–Si–Mg cast alloy

    International Nuclear Information System (INIS)

    A standard Aluminum–Silicon–Magnesium cast alloy (A357 foundry alloy without Beryllium) modified with different weight percentages of Scandium (Sc), has been studied to evaluate the effects of Sc contents on microstructure and strength. Study has been conducted under optimized parameters of melting, casting and heat treatment. Characterization techniques like optical microscopy, SEM, TEM and tensile testing were employed to analyze the microstructure and mechanical properties. Results obtained in this research indicate that with the increase of Sc contents up to 0.4 wt%, grain size is decreased by 80% while ultimate tensile strength and hardness are increased by 28% and 19% respectively. Moreover along with the increase in strength, elongation to failure is also increased up to 165%. This is quite interesting behavior because usually strength and ductility have inverse relationship

  16. A primer on exterior differential calculus

    OpenAIRE

    Burton D.A.

    2003-01-01

    A pedagogical application-oriented introduction to the cal­culus of exterior differential forms on differential manifolds is presented. Stokes' theorem, the Lie derivative, linear con­nections and their curvature, torsion and non-metricity are discussed. Numerous examples using differential calculus are given and some detailed comparisons are made with their tradi­tional vector counterparts. In particular, vector calculus on R3 is cast in terms of exterior calculus and the traditional Stokes'...

  17. Yield Improvement in Steel Casting (Yield II)

    Energy Technology Data Exchange (ETDEWEB)

    Richard A. Hardin; Christoph Beckermann; Tim Hays

    2002-02-18

    This report presents work conducted on the following main projects tasks undertaken in the Yield Improvement in Steel Casting research program: Improvement of Conventional Feeding and Risering Methods, Use of Unconventional Yield Improvement Techniques, and Case Studies in Yield Improvement. Casting trials were conducted and then simulated using the precise casting conditions as recorded by the participating SFSA foundries. These results present a statistically meaningful set of experimental data on soundness versus feeding length. Comparisons between these casting trials and casting trials performed more than forty years ago by Pellini and the SFSA are quite good and appear reasonable. Comparisons between the current SFSA feeding rules and feeding rules based on the minimum Niyama criterion reveal that the Niyama-based rules are generally less conservative. The niyama-based rules also agree better with both the trials presented here, and the casting trails performed by Pellini an d the SFSA years ago. Furthermore, the use of the Niyama criterion to predict centerline shrinkage for horizontally fed plate sections has a theoretical basis according to the casting literature reviewed here. These results strongly support the use of improved feeding rules for horizontal plate sections based on the Niyama criterion, which can be tailored to the casting conditions for a given alloy and to a desired level of soundness. The reliability and repeatability of ASTM shrinkage x-ray ratings was investigated in a statistical study performed on 128 x-rays, each of which were rated seven different times. A manual ''Feeding and Risering Guidelines for Steel Castings' is given in this final report. Results of casting trials performed to test unconventional techniques for improving casting yield are presented. These use a stacked arrangement of castings and riser pressurization to increase the casting yield. Riser pressurization was demonstrated to feed a casting up to

  18. Clean cast steel technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bates, C.E.; Griffin, J.A.

    1998-06-01

    This report documents the results obtained from the Clean Cast Steel Technology Program financially supported by the DOE Metal Casting Competitiveness Research Program and industry. The primary objective of this program is to develop technology for delivering steel free of oxide macroinclusions to mold cavities. The overall objective is to improve the quality of cast steel by developing and demonstrating the technology for substantially reducing surface and sub-surface oxide inclusions. Two approaches are discussed here. A total of 23 castings were produced by submerge pouring along with sixty conventionally poured castings. The submerged poured castings contained, on average, 96% fewer observable surface inclusions (11.9 vs 0.4) compared to the conventionally poured cast parts. The variation in the population of surface inclusions also decreased by 88% from 5.5 to 0.7. The machinability of the casting was also improved by submerged pouring. The submerge poured castings required fewer cutting tool changes and less operator intervention during machining. Subsequent to these trials, the foundry has decided to purchase more shrouds for continued experimentation on other problem castings where submerge pouring is possible. An examination of melting and pouring practices in four foundries has been carried out. Three of the four foundries showed significant improvement in casting quality by manipulating the melting practice. These melting practice variables can be grouped into two separate categories. The first category is the pouring and filling practice. The second category concerns the concentration of oxidizable elements contained in the steel. Silicon, manganese, and aluminum concentrations were important factors in all four foundries. Clean heats can consistently be produced through improved melting practice and reducing exposure of the steel to atmospheric oxygen during pouring and filling.

  19. Effect of bionic coupling units' forms on wear resistance of gray cast iron under dry linear reciprocating sliding condition

    Science.gov (United States)

    Pang, Zuobo; Zhou, Hong; Xie, Guofeng; Cong, Dalong; Meng, Chao; Ren, Luquan

    2015-07-01

    In order to get close to the wear form of guide rails, the homemade linear reciprocating wear testing machine was used for the wear test. In order to improve the wear-resistance of gray cast iron guide rail, bionic coupling units of different forms were manufactured by a laser. Wear behavior of gray-cast-iron with bionic-coupling units has been studied under dry sliding condition at room temperature using the wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that bionic coupling unit could improve the wear resistance of gray cast iron. The wear resistance of gray cast iron with reticulation bionic coupling unit is the best. When the load and speed changed, reticulation bionic coupling unit still has excellent performance in improving the wear resistance of gray cast iron.

  20. Insights into hydrological regime of Lake Vostok from differential behavior of deuterium and oxygen-18 in accreted ice

    Science.gov (United States)

    Ekaykin, A. A.; Lipenkov, V. Y.; Petit, J. R.; Johnsen, S.; Jouzel, J.; Masson-Delmotte, V.

    2010-05-01

    We use isotopic data (deuterium and oxygen-18) of the recently recovered deepest Vostok ice core section (down to 3650 m depth) to study processes leading to the formation of lake ice and the hydrological regime of subglacial Lake Vostok. The significant variability of the lake ice isotopic content implies fluctuations in physical conditions of ice formation (mainly, volume and/or growth rate of frazil ice crystals) as well as variations of the isotope composition of the freezing water. The latter implies a poor mixing of the source waters (glacier melt and hydrothermal water) with the water of the main lake body. Poor mixing within the lake may have important consequences for the lake's chemical and gas balance and, particularly, for its microbiological content. A poorly mixed lake may provide ecological niches where microbial life can hide from high oxygen concentrations likely typical for the lake. We also show that the isotopic content of the main lake's input (meltwater) significantly differs from that of the output (lake ice), which can be explained by the contribution of an additional (hydrothermal) source. This latter conclusion is supported by the observed noncovariant behavior of deuterium and oxygen-18 isotopes in the lake ice.