On the Role of Dilute Solute Additions on Growth Restriction in Binary Copper Alloys

The effect of dilute solute additions on growth restriction in binary Cu alloys has been assessed at different degrees of superheat. Columnar grain length values from Northcott\u2019s work (Northcott in J Inst Metals 62:101-136, 1938) for binary Cu alloys were plotted against the corresponding undercooling parameter (P), the reciprocal of the conventional (Qconv.) and true (Qtrue) growth restriction factor (Schmid-Fetzer and Kozlov in Acta Mater 59(15):6133-6144, 2011) values. It was found that there was no correlation between the columnar grain length values and P, 1/Qconv. and 1/Qtrue values for different solutes and cast at the same degree of superheat. Unlike P, Qconv., and Qtrue values, the heuristic growth restriction parameter (\u3b2) (Fan et al. in Acta Mater 152, 248-257, 2018) modeling framework in conjunction with the critical solute content (C*) for growth restriction fitted well to binary Cu alloys

The Role of Dilute Solute Additions on Growth Restriction in Cu-, Al-, Mg- and Ti-Based Alloys

The effect of dilute solute additions on growth restriction in Cu-, Al-, Mg- and Ti-based binary and ternary alloys was assessed by means of the heuristic growth restriction parameter (β) modelling framework. The CALPHAD (calculation of phase diagrams) methodology was used to calculate β values from the m and k values, at first approximation, as well as from the liquid-to-solid fraction to obtain true β values. Grain size values from the literature were plotted against the corresponding true β values, showing a negative or inverse correlation between the two

Thermal expansivity and degradation properties of PLA/HA and PLA/ bTCP in vitro conditioned composites

[EN] The objective of this study was to investigate the thermal expansivities and degradation properties for several in vitro conditioned biodegradable poly(lactic acid)/hydroxyapatite (PLA/HA) and poly(lactic acid)/b-tricalcium phosphate (PLA/ bTCP) composites with different mass% of the particle reinforcements (i.e. 10, 20 and 30). The samples were prepared by extrusion followed by injection moulding and incubated in a customized simulated body fluid at 37 C over 60, 90, 120, 150 and 180 days, respectively. Thermal expansion and degradation properties of in vitro conditioned samples, along with dynamic mechanical properties of unconditioned ones, were systematically investigated through coefficients of linear thermal expansion and thermal strain changes, decomposition temperatures, mass changes and per cent residues. The results indicated that PLA/bTCP composites performed better than PLA/HA composites, irrespective of their filler mass%, revealing high values of glass transition temperatures, around a mean value of 65 C, both on dynamic mechanical analysis and on dilatation measurements but lower values on their degradation temperatures, such as 360 C. The results suggest the feasibility of tailoring high-loaded osteoconductive fillers-reinforced PLA composites for various medical and engineering applications.Ferri, JM.; Motoc, DL.; Ferrándiz Bou, S.; Balart, R. (2019). Thermal expansivity and degradation properties of PLA/HA and PLA/ bTCP in vitro conditioned composites. Journal of Thermal Analysis and Calorimetry (Online). 138(4):2691-2702. https://doi.org/10.1007/s10973-019-08799-0S269127021384Auras R, Lim LT, Selke S, Tsuji H. Poly(lactic acid): structures, production, synthesis, and applications. New York: Wiley; 2010.Murariu M, Dubois P. PLA composites: from production to properties. Adv Drug Deliv Rev. 2016;107:17–46.Haaparanta A-M, Haimi S, Ellä V, Hopper N, Miettinen S, Suuronen R, et al. Porous polylactide/β-tricalcium phosphate composite scaffolds for tissue engineering applications. J Tissue Eng Regen Med. 2010;4(5):366–73.Ahmed J, Varshney SK. Polylactides—chemistry, properties and green packaging technology: a review. Int J Food Prop. 2011;14(1):37–58.Garlotta D. A literature review of poly(lactic acid). J Polym Environ. 2001;9(2):63–84.Slomkowski S, Penczek S, Duda A. Polylactides—an overview. Polym Adv Technol. 2014;25(5):436–47.Avinc O, Khoddami A. Overview of poly(lactic acid) (PLA) fibre. Fibre Chem. 2009;41(6):391–401.Akindoyo JO, Beg MDH, Ghazali S, Heim HP, Feldmann M. Impact modified PLA-hydroxyapatite composites—thermo-mechanical properties. Compos A Appl Sci Manuf. 2018;107:326–33.Nazhat SN, Kellomäki M, Törmälä P, Tanner KE, Bonfield W. Dynamic mechanical characterization of biodegradable composites of hydroxyapatite and polylactides. J Biomed Mater Res. 2001;58(4):335–43.Ignjatovic N, Uskokovic D. Synthesis and application of hydroxyapatite/polylactide composite biomaterial. Appl Surf Sci. 2004;238(1):314–9.Li J, Zheng W, Li L, Zheng Y, Lou X. Thermal degradation kinetics of g-HA/PLA composite. Thermochim Acta. 2009;493(1):90–5.Zhang SM, Liu J, Zhou W, Cheng L, Guo XD. Interfacial fabrication and property of hydroxyapatite/polylactide resorbable bone fixation composites. Curr Appl Phys. 2005;5(5):516–8.Akindoyo JO, Beg MDH, Ghazali S, Heim HP, Feldmann M. Effects of surface modification on dispersion, mechanical, thermal and dynamic mechanical properties of injection molded PLA-hydroxyapatite composites. Compos A Appl Sci Manuf. 2017;103:96–105.Kang Y, Yao Y, Yin G, Huang Z, Liao X, Xu X, et al. A study on the in vitro degradation properties of poly(l-lactic acid)/β-tricalcuim phosphate(PLLA/β-TCP) scaffold under dynamic loading. Med Eng Phys. 2009;31(5):589–94.Huang J, Ten E, Liu G, Finzen M, Yu W, Lee JS, et al. Biocomposites of pHEMA with HA/β-TCP (60/40) for bone tissue engineering: swelling, hydrolytic degradation, and in vitro behavior. Polymer. 2013;54(3):1197–207.Bleach NC, Nazhat SN, Tanner KE, Kellomäki M, Törmälä P. Effect of filler content on mechanical and dynamic mechanical properties of particulate biphasic calcium phosphate—polylactide composites. Biomaterials. 2002;23(7):1579–85.Ferri J, Gisbert I, García-Sanoguera D, Reig M, Balart R. The effect of beta-tricalcium phosphate on mechanical and thermal performances of poly(lactic acid). J Compos Mater. 2016;50(30):4189–98.Li X, Qi C, Han L, Chu C, Bai J, Guo C, et al. Influence of dynamic compressive loading on the in vitro degradation behavior of pure PLA and Mg/PLA composite. Acta Biomater. 2017;64:269–78.Agrawal CM, McKinney JS, Lanctot D, Athanasiou KA. Effects of fluid flow on the in vitro degradation kinetics of biodegradable scaffolds for tissue engineering. Biomaterials. 2000;21(23):2443–52.Kikuchi M, Koyama Y, Takakuda K, Miyairi H, Shirahama N, Tanaka J. In vitro change in mechanical strength of β-tricalcium phosphate/copolymerized poly-L-lactide composites and their application for guided bone regeneration. J Biomed Mater Res. 2002;62(2):265–72.Lim LT, Auras R, Rubino M. Processing technologies for poly(lactic acid). Prog Polym Sci. 2008;33(8):820–52.Ignjatovic N, Suljovrujic E, Budinski-Simendic J, Krakovsky I, Uskokovic D. Evaluation of hot-pressed hydroxyapatite/poly-L-lactide composite biomaterial characteristics. J Biomed Mater Res B Appl Biomater. 2004;71B(2):284–94.Martin C. Twin screw extrusion for pharmaceutical processes. In: Repka MA, Langley N, DiNunzio J, editors. Melt extrusion: materials, technology and drug product design. New York: Springer; 2013. p. 47–79.Cox SC, Thornby JA, Gibbons GJ, Williams MA, Mallick KK. 3D printing of porous hydroxyapatite scaffolds intended for use in bone tissue engineering applications. Mater Sci Eng C. 2015;47:237–47.Corcione C, Scalera F, Gervaso F, Montagna F, Sannino A, Maffezzoli A. One-step solvent-free process for the fabrication of high loaded PLA/HA composite filament for 3D printing. J Therm Anal Calorim. 2018;134:1–8.Siqueira L, Passador FR, Costa MM, Lobo AO, Sousa E. Influence of the addition of β-TCP on the morphology, thermal properties and cell viability of poly (lactic acid) fibers obtained by electrospinning. Mater Sci Eng C. 2015;52:135–43.Drummer D, Cifuentes-Cuéllar S, Rietzel D. Suitability of PLA/TCP for fused deposition modeling. Rapid Prototyp J. 2012;18(6):500–7.Ferri J, Jordá J, Montanes N, Fenollar O, Balart R. Manufacturing and characterization of poly(lactic acid) composites with hydroxyapatite. J Thermoplast Compos Mater. 2018;31(7):865–81.Menczel JD, Prime RB. Thermal analysis of polymers: fundamentals and applications. New York: Wiley; 2014.Aboudi J, Arnold SM, Bednarcyk BA. Chapter 3—fundamentals of the mechanics of multiphase materials. In: Aboudi J, Arnold SM, Bednarcyk BA, editors. Micromechanics of composite materials. Oxford: Butterworth-Heinemann; 2013. p. 87–145.Esposito Corcione C, Gervaso F, Scalera F, Padmanabhan SK, Madaghiele M, Montagna F, et al. Highly loaded hydroxyapatite microsphere/PLA porous scaffolds obtained by fused deposition modelling. Ceram Int. 2018;45:2803–10.Zou H, Yi C, Wang L, Liu H, Xu W. Thermal degradation of poly(lactic acid) measured by thermogravimetry coupled to Fourier transform infrared spectroscopy. J Therm Anal Calorim. 2009;97(3):929.Schindler A, Doedt M, Gezgin Ş, Menzel J, Schmölzer S. Identification of polymers by means of DSC, TG, STA and computer-assisted database search. J Therm Anal Calorim. 2017;129(2):833–42.Lee WA, Knight GJ. Ratio of the glass transition temperature to the melting point in polymers. Br Polym J. 1970;2(1):73–80

An Instruction to Accelerate Software Caches

In this paper we propose an instruction to accelerate software caches. While DMAs are very efficient for predictable data sets that can be fetched before they are needed, they introduce a large latency overhead for computations with unpredictable access behavior. Software caches are advantageous when the data set is not predictable but exhibits locality. However, software caches also incur a large overhead. Because the main overhead is in the access function, we propose an instruction that replaces the look-up function of the software cache. This instruction is evaluated using the Multidimensional Software Cache and two multimedia kernels, GLCM and H.264 Motion Compensation. The results show that the proposed instruction accelerates the software cache access time by a factor of 2.6. This improvement translates to a 2.1 speedup for GLCM and 1.28 for MC, when compared with the IBM software cache

Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes

Liquid silicone rubber is an interesting material at an industrial level, but there are great difficulties in the design and machining of molds, and in addition, it cannot be processed using conventional equipment. Therefore, new lines of research have focused on the search for new materials capable of providing final properties similar to liquid silicone rubber, that can also be engineered using simple, conventional processes and machinery. In this investigation, a range of compatible blends, based on two commercial grades of styrene-b-ethyleneco- butylene-b-styrene (SEBS) thermoplastic elastomer, was studied in order to obtain a range of different Shore A hardness blends for industrial applications where liquid silicone rubber (different hardness) is currently used. The two blended elastomers used had widely differing Shore A hardness values (5 and 90). Once the blended materials had been characterized, the Cross and Williams et al. [20] (Cross-WLF) mathematical model was applied in order to obtain theoretical performance curves for the viscosity of each of the blends. After this, a model was developed using the Computer Aided Engineering (CAE) software package Autodesk Moldflow 2012TM. This computer modeling validated the results obtained from the mathematical models, thus making available to process engineers the full range of hardnesses necessary for industrial products (where liquid silicone rubber is used), while still providing the advantages of thermoplastic injection molding.The authors wish to thank "Ministerio de Ciencia e Innovacion" IPT-310000-2010-37 and Universidad Politecnica de Valencia PAID 10012 for their financial support.Juárez Varón, D.; R. Balart; T. Boronat; Reig Pérez, MJ.; Ferrándiz Bou, S. (2013). Validation of the Use of SEBS Blends as a Substitute for Liquid Silicone Rubber in Injection Processes. Materials and Manufacturing Processes. 28(11):1215-1221. doi:10.1080/10426914.2013.811732S121512212811Zhang, B., Wong, J. S.-P., Shi, D., Yam, R. C.-M., & Li, R. K.-Y. (2010). Investigation on the mechanical performances of ternary nylon 6/SEBS elastomer/nano-SiO2hybrid composites with controlled morphology. Journal of Applied Polymer Science, 115(1), 469-479. doi:10.1002/app.30185Su, F.-H., & Huang, H.-X. (2009). Mechanical and rheological properties of PP/SEBS/OMMT ternary composites. Journal of Applied Polymer Science, 112(5), 3016-3023. doi:10.1002/app.29875Sugimoto, M., Sakai, K., Aoki, Y., Taniguchi, T., Koyama, K., & Ueda, T. (2009). Rheology and morphology change with temperature of SEBS/hydrocarbon oil blends. Journal of Polymer Science Part B: Polymer Physics, 47(10), 955-965. doi:10.1002/polb.21699Jose, A. J., Alagar, M., & P. Thomas, S. (2012). Preparation and Characterization of Organoclay Filled Polysulfone Nanocomposites. Materials and Manufacturing Processes, 27(3), 247-254. doi:10.1080/10426914.2011.585490Ivanović, N., Marjanović, N., Grbović Novaković, J., Manasijević, M., Rakočević, Z., Andrić, V., & Hadžić, B. (2009). Experimental and Theoretical Investigations of Cured and Uncured Disiloxane Bisbenzocyclobutene Thin Films. Materials and Manufacturing Processes, 24(10-11), 1180-1184. doi:10.1080/10426910902978811Perisić, M., Radojević, V., Uskoković, P. S., Stojanović, D., Jokić, B., & Aleksić, R. (2009). Wood–Thermoplastic Composites Based on Industrial Waste and Virgin High-Density Polyethylene (HDPE). Materials and Manufacturing Processes, 24(10-11), 1207-1213. doi:10.1080/10426910903032212Iqbal, H., Sheikh, A. K., Al-Yousef, A., & Younas, M. (2012). Mold Design Optimization for Sand Casting of Complex Geometries Using Advance Simulation Tools. Materials and Manufacturing Processes, 27(7), 775-785. doi:10.1080/10426914.2011.648250Özek, C., & Çelık, Y. H. (2011). Calculating Molding Parameters in Plastic Injection Molds with ANN and Developing Software. Materials and Manufacturing Processes, 27(2), 160-168. doi:10.1080/10426914.2011.560224Hirschmanner, M., Mörwald, K., & Fröhlich, C. (2011). Next Generation Mold Level Control: Development of LevCon 2.0. Materials and Manufacturing Processes, 26(1), 169-174. doi:10.1080/10426910903206691Selvakumar, P., & Bhatnagar, N. (2009). Studies on Polypropylene/Carbon Fiber Composite Foams by Nozzle-Based Microcellular Injection Molding System. Materials and Manufacturing Processes, 24(5), 533-540. doi:10.1080/10426910902742738Gramegna, N., Corte, E. D., & Poles, S. (2011). Manufacturing Process Simulation for Product Design Chain Optimization. Materials and Manufacturing Processes, 26(3), 527-533. doi:10.1080/10426914.2011.564248Marković, G., Radovanović, B., Marinović-Cincović, M., & Budinski-Simendić, J. (2009). The Effect of Accelerators on Curing Characteristics and Properties of Natural Rubber/Chlorosulphonated Polyethylene Rubber Blend. Materials and Manufacturing Processes, 24(10-11), 1224-1228. doi:10.1080/10426910902967087Mehat, N. M., & Kamaruddin, S. (2011). Investigating the Effects of Injection Molding Parameters on the Mechanical Properties of Recycled Plastic Parts Using the Taguchi Method. Materials and Manufacturing Processes, 26(2), 202-209. doi:10.1080/10426914.2010.529587Chen, C.-C., Su, P.-L., Chiou, C.-B., & Chiang, K.-T. (2011). Experimental Investigation of Designed Parameters on Dimension Shrinkage of Injection Molded Thin-Wall Part by Integrated Response Surface Methodology and Genetic Algorithm: A Case Study. Materials and Manufacturing Processes, 26(3), 534-540. doi:10.1080/10426914.2010.530331Martinez, A., Castany, J., & Aisa, J. (2011). Characterization of In-Mold Decoration Process and Influence of the Fabric Characteristics in This Process. Materials and Manufacturing Processes, 26(9), 1164-1172. doi:10.1080/10426914.2010.536934Primo Benitez-Rangel, J., Trejo-Hernández, M., Alberto Morales-Hernández, L., & Domínguez-González, A. (2010). Improvement of the Injection Mold Process by Using Vibration Through a Mold Accessory. Materials and Manufacturing Processes, 25(7), 577-580. doi:10.1080/10426910903124902Chen, C.-C. (2011). Design of Effective Parameters on the Wick-Debinding Process for Powder Injection Molded Green Compact. Materials and Manufacturing Processes, 26(10), 1261-1268. doi:10.1080/10426914.2010.544826Boronat, T., Segui, V. J., Peydro, M. A., & Reig, M. J. (2009). Influence of temperature and shear rate on the rheology and processability of reprocessed ABS in injection molding process. Journal of Materials Processing Technology, 209(5), 2735-2745. doi:10.1016/j.jmatprotec.2008.06.013Cross, M. M. (1965). Rheology of non-Newtonian fluids: A new flow equation for pseudoplastic systems. Journal of Colloid Science, 20(5), 417-437. doi:10.1016/0095-8522(65)90022-xReig, M. J., Segui, V. J., & Zamanillo, J. D. (2005). Rheological Behavior Modeling of Recycled ABS/PC Blends Applied to Injection Molding Process. Journal of Polymer Engineering, 25(5). doi:10.1515/polyeng.2005.25.5.43

Compatibilization of highly sustainable polylactide/almond shell flour composites by reactive extrusion with maleinized linseed oil

Highly sustainable composites were produced by melt compounding polylactide (PLA) with almond shell flour (ASF), a processed by-product of the food industry, at a constant weight content of 30 wt.-%. However, due to the lack of miscibility between PLA and ASF, both being raw materials obtained from crops, resultant green composite presented poor ductility and low thermal stability. To overcome this limitation, maleinized linseed oil (MLO), a multi-functionalized plant-derived additive, was originally incorporated as a reactive compatibilizer during the extrusion process. Both chemical and physical characterizations showed that 1–5 parts per hundred resin (phr) of MLO successfully serve to obtain PLA/ASF composites with improved mechanical, thermal, and thermomechanical properties. The enhancement achieved was particularly related to a dual compatibilizing effect of plasticization in combination with melt grafting. The latter process was specifically ascribed to the formation of new carboxylic ester bonds through the reaction of the multiple maleic anhydride functionalities present in MLO with the hydroxyl groups of both the PLA terminal chains and cellulose on the ASF surface. The fully bio-based and biodegradable composites described herein give an efficient sustainable solution to upgrade agro-food wastes as well as contributing to reducing the cost of PLA-based materials

Surface Modification of Polypropilene Non-woven Substrates by Padding with Antistatic Agents for Deposition of Polyvinyl Alcohol (PVA) Nanofiber Webs by Electrospinning

In recent years, the electrospinning process has become one of the most interesting processes to obtain nanofiber webs with interesting properties for uses in a wide variety of industrial sectors such as filtration, chemical barriers, medical devices, etc., as a consequence of the relatively high surface-to-volume ratio. Among the wide variety of polymers, polyvinyl alcohol (PVA) offers good advantages since it is water-soluble and this fact enables easy processing by electrospinning. There are many variables and parameters to be considered in order to optimize PVA nanofiber webs: some of them are related to the polymer solution, some others are related to the process, and some of them are related to the collector substrate. In this work a study on the effects of two different surface pre-treatments on a nonwoven polypropylene substrate as a collector of PVA nanofiber webs has been carried out. In particular, a chemical treatment with anionic antistatics and a physical treatment with lowpressure plasma have been investigated. The effects of these pre-treatments on morphology of PVA nanofiber webs have been evaluated by scanning electron microscopy. Results show that surface resistivity is one of the main parameters influencing the web formation as well as the nature of the electric charge achieved by the pre-treatment. The plasma treatment promotes changes in surface resistivity but it is not enough for good web deposition. Chemical pre-treatment (padding) with anionic antistatic leads to a decrease in surface resistivity up to values in the 1 × 109– 1 × 1011 Ω which is enough for good nanofiber deposition.This work was supported by the Ministerio de Ciencia y Tecnologia, grant number DPI2007-66849-C02-02.Blanes, M.; Marco, B.; Gisbert, MJ.; Bonet Aracil, MA.; Balart Gimeno, RA. (2010). Surface Modification of Polypropilene Non-woven Substrates by Padding with Antistatic Agents for Deposition of Polyvinyl Alcohol (PVA) Nanofiber Webs by Electrospinning. Textile Research Journal. 80(13):1335-1346. https://doi.org/10.1177/0040517509358801S133513468013Burger, C., Hsiao, B. S., & Chu, B. (2006). NANOFIBROUS MATERIALS AND THEIR APPLICATIONS. Annual Review of Materials Research, 36(1), 333-368. doi:10.1146/annurev.matsci.36.011205.123537Dersch, R., Steinhart, M., Boudriot, U., Greiner, A., & Wendorff, J. H. (2005). Nanoprocessing of polymers: applications in medicine, sensors, catalysis, photonics. Polymers for Advanced Technologies, 16(2-3), 276-282. doi:10.1002/pat.568Frenot, A., & Chronakis, I. S. (2003). Polymer nanofibers assembled by electrospinning. Current Opinion in Colloid & Interface Science, 8(1), 64-75. doi:10.1016/s1359-0294(03)00004-9GOPAL, R., KAUR, S., MA, Z., CHAN, C., RAMAKRISHNA, S., & MATSUURA, T. (2006). Electrospun nanofibrous filtration membrane. Journal of Membrane Science, 281(1-2), 581-586. doi:10.1016/j.memsci.2006.04.026Qin, X.-H., & Wang, S.-Y. (2006). Filtration properties of electrospinning nanofibers. Journal of Applied Polymer Science, 102(2), 1285-1290. doi:10.1002/app.24361Ren, G., Xu, X., Liu, Q., Cheng, J., Yuan, X., Wu, L., & Wan, Y. (2006). Electrospun poly(vinyl alcohol)/glucose oxidase biocomposite membranes for biosensor applications. Reactive and Functional Polymers, 66(12), 1559-1564. doi:10.1016/j.reactfunctpolym.2006.05.005Lee, S., & Obendorf, S. K. (2007). Use of Electrospun Nanofiber Web for Protective Textile Materials as Barriers to Liquid Penetration. Textile Research Journal, 77(9), 696-702. doi:10.1177/0040517507080284Heikkilä, P., Sipilä, A., Peltola, M., Harlin, A., & Taipale, A. (2007). Electrospun PA-66 Coating on Textile Surfaces. Textile Research Journal, 77(11), 864-870. doi:10.1177/0040517507078241Boudriot, U., Dersch, R., Greiner, A., & Wendorff, J. H. (2006). Electrospinning Approaches Toward Scaffold Engineering?A Brief Overview. Artificial Organs, 30(10), 785-792. doi:10.1111/j.1525-1594.2006.00301.xButtafoco, L., Kolkman, N. G., Engbers-Buijtenhuijs, P., Poot, A. A., Dijkstra, P. J., Vermes, I., & Feijen, J. (2006). Electrospinning of collagen and elastin for tissue engineering applications. Biomaterials, 27(5), 724-734. doi:10.1016/j.biomaterials.2005.06.024Lee, L. J. (2006). Polymer Nanoengineering for Biomedical Applications. Annals of Biomedical Engineering, 34(1), 75-88. doi:10.1007/s10439-005-9011-6Chew, S. Y., Hufnagel, T. C., Lim, C. T., & Leong, K. W. (2006). Mechanical properties of single electrospun drug-encapsulated nanofibres. Nanotechnology, 17(15), 3880-3891. doi:10.1088/0957-4484/17/15/045Huang, Z.-M., He, C.-L., Yang, A., Zhang, Y., Han, X.-J., Yin, J., & Wu, Q. (2006). Encapsulating drugs in biodegradable ultrafine fibers through co-axial electrospinning. Journal of Biomedical Materials Research Part A, 77A(1), 169-179. doi:10.1002/jbm.a.30564Kim, H.-W., Lee, H.-H., & Knowles, J. C. (2006). Electrospinning biomedical nanocomposite fibers of hydroxyapatite/poly(lactic acid) for bone regeneration. Journal of Biomedical Materials Research Part A, 79A(3), 643-649. doi:10.1002/jbm.a.30866Taepaiboon, P., Rungsardthong, U., & Supaphol, P. (2006). Drug-loaded electrospun mats of poly(vinyl alcohol) fibres and their release characteristics of four model drugs. Nanotechnology, 17(9), 2317-2329. doi:10.1088/0957-4484/17/9/041Ding, B., Kim, H.-Y., Lee, S.-C., Shao, C.-L., Lee, D.-R., Park, S.-J., … Choi, K.-J. (2002). Preparation and characterization of a nanoscale poly(vinyl alcohol) fiber aggregate produced by an electrospinning method. Journal of Polymer Science Part B: Polymer Physics, 40(13), 1261-1268. doi:10.1002/polb.10191Cui, W., Li, X., Zhou, S., & Weng, J. (2006). Investigation on process parameters of electrospinning system through orthogonal experimental design. Journal of Applied Polymer Science, 103(5), 3105-3112. doi:10.1002/app.25464Deitzel, J. ., Kleinmeyer, J., Harris, D., & Beck Tan, N. . (2001). The effect of processing variables on the morphology of electrospun nanofibers and textiles. Polymer, 42(1), 261-272. doi:10.1016/s0032-3861(00)00250-0Lyons, J., Li, C., & Ko, F. (2004). Melt-electrospinning part I: processing parameters and geometric properties. Polymer, 45(22), 7597-7603. doi:10.1016/j.polymer.2004.08.071Theron, S. A., Zussman, E., & Yarin, A. L. (2004). Experimental investigation of the governing parameters in the electrospinning of polymer solutions. Polymer, 45(6), 2017-2030. doi:10.1016/j.polymer.2004.01.024Kilic, A., Oruc, F., & Demir, A. (2008). Effects of Polarity on Electrospinning Process. Textile Research Journal, 78(6), 532-539. doi:10.1177/0040517507081296Reneker, D. H., & Chun, I. (1996). 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Switch between morphospecies of pocillopora corals

© 2015 by The University of Chicago. All rights reserved. Pocillopora corals are the main reef builders in the eastern tropical Pacific. The validity of Pocillopora morphospecies remains under debate because of disagreements between morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of California for 44 months. Twenty-three percent of tagged colonies of Pocillopora damicornis changed to Pocillopora inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e., lower chlorophyll a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochondrial identity, but most P. damicornis colonies undergoing change were at a site with low-flow conditions. This is the first in situ study to document switching between described morphospecies, and it elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses

Automated SEM/EDS analysis for assessment of trace cross-contamination in 316L stainless steel powders

Following observations of microcracking in two, out of three, Additive manufactured (AM) 316L steel samples, an investigation was undertaken to ascertain the root cause. Welding diagrams, taking into account composition and process parameters, could not generally account for the experimental observations of non-cracked versus cracked AM 316L samples. EBSD phase maps in all three AM samples exhibited a fully austenitic microstructure not only in the bulk sample but also near-surface. Analysis of microcracked regions in the AM samples showed the presence of local enrichment of Ni, Cu and P. Automated SEM/EDS analysis on feedstock powder samples prepared for cross-section examination revealed a fine, foreign particulate contaminant, expected to arise from NiCrCuP alloy cross-contamination during atomization, to be completely embedded in a 316L powder particle. This type of contamination would not have been revealed on examination of powder mounted onto a SEM stub, a common approach to assess powder quality. Based on this analysis, it is recommended to consider including automated SEM/EDS analysis on powder cross-sections in any standardization protocol for quality control of powders, to increase the chances of detection and identification of fine cross-contaminants. It is also recommended that atomization of NiCrCuP alloy should no longer precede atomization of 316L alloy