The appearance of deterge nt powder plays an importa nt role in con sumer perception of powder effectiveness for cleaning applications. In this study, we investigated the influence of numerous formulation and processi...The appearance of deterge nt powder plays an importa nt role in con sumer perception of powder effectiveness for cleaning applications. In this study, we investigated the influence of numerous formulation and processing conditions on product discoloration. Product color was scrutinized using the L*a*b* color space, and in particular, L* and b*. Particle size, the method for introducing the optical brightener, and the raw material grade were very important in con trolling the optical properties of detergent granules. As the particle size decreased, the light reflected to the observer appeared brighter and bluer. This was observed as increased whiteness from L*= 84.03 with a particle size of >841 μm to L*= 90.59 with a particle size of <250 μm. Reducing the level of impurities found in the raw materials by changing the material source also improved color definition. A key finding is that the optical brightener should be applied by spraying and prepared by dispersion rather than dissolution. This improves the distribution within the granules and increases the whiteness when compared with pouring the brightener into the agglomeration vessel. Additional spray applications highlighted that brightener on the granule surface influenced whiteness more than embedded brightener. In addition, we report on the effects of the drying temperature and mixer impeller speed on powder color.展开更多
We examined the applicability of the pumice aggregate on the concrete formed by considering the reactive powder concrete mixture ratios, for the rigid superstructure concrete road pavement and building construction. T...We examined the applicability of the pumice aggregate on the concrete formed by considering the reactive powder concrete mixture ratios, for the rigid superstructure concrete road pavement and building construction. The natural pumice aggregate in fibrous and non-fibrous concrete samples was used in the production of concrete by fracturing in 0.1-0.6 mm dimensions in rotor mill. The concreted formed in this way is named after the pumice powder concrete(PPC). The PPC samples produced were taken 7 days as 20 ℃ standard water cure, 28 days as 20 ℃ standard cure and 9 different types of combined cures. The combined cures were applied different temperatures in different durations. PPC samples were subjected to some pressure and flexural tests at the end of the standard water and combined cures. The highest compressive and flexural strengths of PPC samples were obtained after the combined cures: 3 days in 20 ℃ as standard water curing + 2 days in 180 ℃ in drying-oven. The highest compressive strength of PPC samples without any fiber was found to be 47.27 MPa, as for the highest flexural strength, it is found to be 5.23 MPa, in the end of the study. The highest compressive strength of fibrous PPC samples was 51.12 MPa, while flexural strength was 6.57 MPa.展开更多
This research explores the prospect of fabricating a face-centered cubic(fcc) Ni-base alloy cladding(Inconel 690) on an fcc Fe-base alloy(316 L stainless-steel) having improved mechanical properties and reduced sensit...This research explores the prospect of fabricating a face-centered cubic(fcc) Ni-base alloy cladding(Inconel 690) on an fcc Fe-base alloy(316 L stainless-steel) having improved mechanical properties and reduced sensitivity to corrosion through grain boundary and microstructure engineering concepts enabled by additive manufacturing(AM) utilizing electron-beam powder bed fusion(EPBF). The unique solidification and associated constitutional supercooling phenomena characteristic of EPBF promotes[100] textured and extended columnar grains having lower energy grain boundaries as opposed to random, high-angle grain boundaries, but no coherent {111} twin boundaries characteristic of conventional thermo-mechanically processed fcc metals and alloys, including Inconel 690 and 316 L stainless-steel.In addition to [100] textured grains, columnar grains were produced by EPBF fabrication of Inconel 690 claddings on 316 L stainless-steel substrates. Also, irregular 2–3 μm diameter, low energy subgrains were formed along with dislocation densities varying from 108 to 109 cm2, and a homogeneous distribution of Cr23C6 precipitates. Precipitates were formed within the grains(with 3 μm interparticle spacing),but not in the subgrain or columnar grain boundaries. These inclusive, hierarchical microstructures produced a tensile yield strength of 0.527 GPa, elongation of 21%, and Vickers microindentation hardness of 2.33 GPa for the Inconel 690 cladding in contrast to a tensile yield strength of 0.327 GPa, elongation of 53%, and Vickers microindentation hardness of 1.78 GPa, respectively for the wrought 316 L stainlesssteel substrate. Aging of both the Inconel 690 cladding and the 316 L stainless-steel substrate at 685?C for50 h precipitated Cr23C6 carbides in the Inconel 690 columnar grain boundaries, but not in the low-angle(and low energy) subgrain boundaries. In contrast, Cr23C6 carbides precipitated in the 316 L stainless-steel grain boundaries, but not in the low energy coherent {111} twin boundaries. Consequently, the Inconel6展开更多
Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and ...Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores.展开更多
Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully ...Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully dense samples were successfully printed using the 3 D systems – ProX 300 printing machine. The ductility and tensile yield strength were almost two and three times higher compared to those of ASTM cast’s alloy. Honey comb like nano-cellular structure with different orientation was observed in the fine grains(~4μm) due to fast cooling rate. In addition, the formation of martensite phase in random grains is also a contributor to the strengths. Furthermore, negative residual stresses in the build and horizontal directions were detected and assisted further increase in the tensile strength. Fractography revealed the ductile feature of plastic deformation and the crack openings at unmelted particles or pores.展开更多
One of the bottleneck issues for commercial scale-up of Ti additive manufacturing lies in high cost of raw material, i.e. the spherical Ti powder that is often made by gas atomization. In this study, we address this s...One of the bottleneck issues for commercial scale-up of Ti additive manufacturing lies in high cost of raw material, i.e. the spherical Ti powder that is often made by gas atomization. In this study, we address this significant issue by way of powder modification & ball milling processing, which shows that it is possible to produce printable Ti powders based on ultra- low cost, originally unprintable hydrogenation-dehydrogenation (HDH) Ti powder. It is also presented that the as-printed Ti using the modified powder exhibits outstanding mechanical properties, showing a combination of excellent fracture strength (~895 MPa) and high ductility (~19.0% elongation).展开更多
This study determined the optimal concentration of titanium diboride (TiB2) particles for the development of in situ titanium– titanium boride (Ti–TiB) metal matrix composites (MMCs) prepared by a conventional powde...This study determined the optimal concentration of titanium diboride (TiB2) particles for the development of in situ titanium– titanium boride (Ti–TiB) metal matrix composites (MMCs) prepared by a conventional powder metallurgy route to be used for industrial applications. The effect of concentration of TiB2 particles was studied by reinforcing TiB2 powder in different mass fractions (2wt%, 5wt%, 10wt%, and 20wt%) into pure Ti powder during the fabrication process. The MMCs were sintered at high temperatures under vacuum. The transmission electron microscopy (TEM) results revealed the formation of needle-shaped TiB whiskers, indicating that in situ reaction occurred during vacuum sintering of the powder compacts. All the composite samples had a high sintered density, and the hardness of the composites increased with an increase in the mass fraction of reinforcement. Mechanical and tribological properties such as flexural strength, impact, and wear properties were determined and found to be dependent on the mass fraction of the reinforcement. However, the mechanism for the in situ reaction needs further investigation by high-energy in situ X-ray diffraction techniques.展开更多
The development and function of the third-party testing platform and the evaluation of detergent products by domestic professional third-party evaluation organizations were summarized. The evaluation methods and index...The development and function of the third-party testing platform and the evaluation of detergent products by domestic professional third-party evaluation organizations were summarized. The evaluation methods and indexes of hand washing dish detergent and fabric detergent by different third-party evaluation organizations were also concluded. The influence of third-party evaluation on the development of detergent products in China is presented.展开更多
Bi-2223 precursor powders are prepared by both oxalate co-precipitation(CP) and spray pyrolysis(SP) methods.The influence of fabrication methods on the superconducting properties of Bi-2223 tapes are systematically st...Bi-2223 precursor powders are prepared by both oxalate co-precipitation(CP) and spray pyrolysis(SP) methods.The influence of fabrication methods on the superconducting properties of Bi-2223 tapes are systematically studied. Compared to the CP method, SP powder exhibits spherical particle before calcination and smaller particle size after calcinations with more uniform chemical composition, which leads to a lower reaction temperature during calcination process for Bi-2223 tapes. Meanwhile, the non-superconducting phases in SP powder are more uniformly distributed with smaller particle sizes. These features result in finer homogeneity of critical current in large-length of Bi-2223 tape, higher density of filaments and better texture after heat treatment. Therefore,the SP method could be considered as a better route to prepare precursor powder for large-length Bi-2223 tape fabrication.展开更多
BACKGROUND Gastrointestinal (GI) bleeding is a common indication for endoscopy. For refractory cases, hemostatic powders (HP) represent “touch-free” agents. AIM To analyze short term (ST-within 72 h-) and long-term ...BACKGROUND Gastrointestinal (GI) bleeding is a common indication for endoscopy. For refractory cases, hemostatic powders (HP) represent “touch-free” agents. AIM To analyze short term (ST-within 72 h-) and long-term (LT-within 30 d-) success for achieving hemostasis with HP and to directly compare the two agents Hemospray (HS) and Endoclot (EC). METHODS HP was applied in 154 consecutive patients (mean age 67 years) with GI bleeding. Patients were followed up for 1 mo (mean follow-up: 3.2 mo). RESULTS Majority of applications were in upper GI tract (89%) with following bleeding sources: peptic ulcer disease (35%), esophageal varices (7%), tumor bleeding (11.7%), reflux esophagitis (8.7%), diffuse bleeding and erosions (15.3%). Overall ST success was achieved in 125 patients (81%) and LT success in 81 patients (67%). Re-bleeding occurred in 27% of all patients. In 72 patients (47%), HP was applied as a salvage hemostatic therapy, here ST and LT success were 81% and 64%, with re-bleeding in 32%. As a primary hemostatic therapy, ST and LT success were 82% and 69%, with re-bleeding occurring in 22%. HS was more frequently applied for upper GI bleeding (P = 0.04) CONCLUSION Both HP allow for effective hemostasis with no differences in ST, LT success and re-bleeding.展开更多
OBJECTIVE: To evaluated the benefits of oral administration of arsenic-containing Qinghuang Powder(QHP)compared with decitabine for patients with high/very-high(H/VH) risk myelodysplastic syndrome(MDS) according to th...OBJECTIVE: To evaluated the benefits of oral administration of arsenic-containing Qinghuang Powder(QHP)compared with decitabine for patients with high/very-high(H/VH) risk myelodysplastic syndrome(MDS) according to the Revised International Prognostic Score System. METHODS: The OS(mOS) rate, annual OS rate and progression to acute myeloid leukemia(AML) in patients with H/VH MDS treated with QHP(QHP group, n = 27) and decitabine(decitabine group, n = 20) were retrospectively analyzed. The effects of prognostic factors of age, proportion of bone marrow blast,peripheral blood cell count, karyotype and Charlson Comorbidity Index(CCI) on OS were further analyzed. RESULTS: The m OS rate of QHP group(29 months) was signi?cantly longer than that of the decitabine group(18 months)(P = 0.043). The OS rates of 1, 2, and 3 years were signi?cantly higher in the QHP group(88.9%, 59.3%, 29.6%) than that in the decitabine group(70%, 25%, and 5%)(P = 0.01). There was no signi?cant difference of 5-year OS rate between the 2 groups(P = 0.133).The effects of prognostic factors on mOS were further analyzed, and it was found that there was no signi?cant difference of m OS rate between the QHP group(29 months) and the decitabine group(21 months) in the patients with age 65 years old(P = 0.673). The mOS rate was signi?cantly longer in QHP group(28.5 months) than that in decitabine group(18 months) in the patients with age of < 65 years old(P = 0.04). The proportions of bone marrow blast cells with 10% or < 10% had no signi?cant effects on the mOS rate of patients in the 2 groups(P = 0.429, P = 0.183). In patients with HGB 80 g/L, mOS rate was signi?cantly longer in the QHP group(57 months) than that in the decitabine group(21 months)(P = 0.047), while in patients with HGB < 80 g/L, there was no signi?cant difference of mOS rate between the 2 groups(P = 0.265). In the patients with PLT < 50×10~9/L, the mOS rate was signi?cantly longer in the QHP group(33 months) than that in the decitabine group(16 months)(P = 0.028). In the patients wi展开更多
The improvement of mechanical properties must be achieved by designing and constructing more suitable microstructure,such as hierarchical microstructure.In order to significantly enhance the creep resistance of titani...The improvement of mechanical properties must be achieved by designing and constructing more suitable microstructure,such as hierarchical microstructure.In order to significantly enhance the creep resistance of titanium matrix composites(TMCs),two-scale network microstructure was constructed including the first-scale network(<150μm)with micro-TiB whisker(TiBw)reinforcement and the second-scale network(<30μm)with nano-Ti5Si3 reinforcement by powder metallurgy and in-situ synthesis.The results showed that the creep rate of the composite was remarkably reduced by an order of magnitude compared with the Ti6Al4V alloy at 550℃,600℃,650℃ under the stresses between 100 MPa and 350 MPa.Moreover,the rupture time of the composite was increased by 20 times,compared with that of the Ti6Al4 Valloy at 550℃/300 MPa.The superior creep resistance could be attributed to the hierarchical microstructure.The micro-TiBw reinforcement in the first-scale network boundary contributed to creep resistance primarily by blocking grain boundary sliding,while the nano-Ti5Si3 particle in the second-scale network boundary mainly by hindering phase boundary sliding.In addition,the nano-Ti5Si3 particle was dissolved,and precipitated with smaller size than the primary Ti5Si3.This phenomenon was attributed to Si element diffusion under high temperature and external stress,which could further continuously enhance the creep resistance.Finally,the creep rate during steady-state stage was significantly decreased,which manifested superior creep resistance of the composite.展开更多
In this study,we developed a powder extruder system that can extrude and deposit powder mixtures to overcome the reported limitations of conventional dualpore scaffold manufacturing methods.To evaluate the extrusion a...In this study,we developed a powder extruder system that can extrude and deposit powder mixtures to overcome the reported limitations of conventional dualpore scaffold manufacturing methods.To evaluate the extrusion and deposition capability of the powder extruder system,3D tissue-engineering scaffolds with dual-pore characteristics were fabricated with a PCL/PEO/NaCl(polycaprolactone/polyethylene oxide/sodium chloride)powder mixture.In addition,to evaluate the fabricated scaffolds,their compressive modulus,morphology,and in-vitro cell activity were assessed.Consequently,it was confirmed that the proposed powder extruder system can fabricate dual-pore scaffolds with well-interconnected pores as well as arbitrary 3D shapes shown by the fabrication of a 3D femur-shape scaffold similar to the femur model.The results of the cell proliferation and Cell Counting Kit-8(CCK-8)assays,DNA content analysis and viability assays confirm that the dual-pore scaffold fabricated by the powder extruder system improves cell attachment,proliferation,and viability.展开更多
This paper presents a manufacturing cost constrained topology optimization algorithm considering the laser powder bed additive manufacturing process.Topology optimization for additive manufacturing was recently extens...This paper presents a manufacturing cost constrained topology optimization algorithm considering the laser powder bed additive manufacturing process.Topology optimization for additive manufacturing was recently extensively studied,and many related topics have been addressed.However,metal additive manufacturing is an expensive process,and the high manufacturing cost severely hinders the widespread use of this technology.Therefore,the proposed algorithm in this research would provide an opportunity to balance the manufheturing cost while pursuing the superior structural perfonnance through topology optimization.Technically,the additive manufacturing cost model for laser powder bed-bascd process is established in this paper and real data is collected to support this model.Then,this cost model is transformed into a level set function-based expression,which is integrated into the level set topology optimization problem as a constraint.Therefore,by properly developing the sensitivity result,the metallic additive manufocturing part can be optimized with strictly constrained manufacturing cost.Effectiveness of the proposed algorithm is proved by numerical design examples.展开更多
[Objectives] The study aimed to protect the good germplasm resources of Himalayan Leycesteria formosa Wall. and produce a large number of L. formosa plants used in Tibetan garden landscape.[Methods] In the intelligent...[Objectives] The study aimed to protect the good germplasm resources of Himalayan Leycesteria formosa Wall. and produce a large number of L. formosa plants used in Tibetan garden landscape.[Methods] In the intelligent solar greenhouse, the effects of different concentrations of ABT2 rooting powder on the cutting propagation of L. formosa twigs were studied, and the effects of different matrices on the growth of the cutting seedlings were analyzed.[Results] The effect of different concentrations of ABT2 rooting powder on the rooting rate of L. formosa is as follows: 200 mg/L>300 mg/L>100 mg/L, and the rooting rate is as follows: 61%>59%>57%. The rooting rate of L. formosa in the control group (CK) was 54%. The average number of roots and the average length of main root of L. formosa in the three treatments with ABT2 rooting powder were significantly different, while the average number of primary roots, average number of new branches, and average number of new leaves of L. formosa treated with 100 mg/L ABT2 rooting powder had no significant difference. There were significant differences between 200 and 300 mg/L ABT2 root powder treatments in the three growth indicators of L. formosa , and the promotion effects of 200 mg/L ABT2 rooting powder on the five indicators of L. formosa cuttings were better. The effects of different transplanting matrices on the indoor survival rate of L. formosa cutting seedlings were very obvious, and the survival rate of L. formosa cutting seedlings in matrix C was the highest, up to 96%. Different substrates had different effects on the growth of ground diameter of L. formosa cutting seedlings, and the promotion effect of matrix C was better.[Conclusions] In the rapid cutting propagation of good L. formosa , 200 mg/L ABT2 rooting powder can be selected. For indoor transplanting, matrix C (sandy soil+perlite+humus soil) should be used.展开更多
Earthworms are important invertebrates that have been widely used as food and traditional medicine sources for thousands of years. Not only have researchers proven that earthworms are rich in proteins and other nutrie...Earthworms are important invertebrates that have been widely used as food and traditional medicine sources for thousands of years. Not only have researchers proven that earthworms are rich in proteins and other nutrients, they have also taken a keener interest in their unique pharmaceutical properties. Recent research has successfully discovered some beneficial functional components of earthworms due to the rapid development of biological technologies in the past decades. Therefore, earthworms could be a novel dietary supplement for human consumption. This review aims to summarize the current research about nutritional and therapeutic values of earthworms;and present a matured earthworm-derived product from Bocom Pharmaceuticals (USA) Corp as an example of its incorporation into a dietary supplement.展开更多
文摘The appearance of deterge nt powder plays an importa nt role in con sumer perception of powder effectiveness for cleaning applications. In this study, we investigated the influence of numerous formulation and processing conditions on product discoloration. Product color was scrutinized using the L*a*b* color space, and in particular, L* and b*. Particle size, the method for introducing the optical brightener, and the raw material grade were very important in con trolling the optical properties of detergent granules. As the particle size decreased, the light reflected to the observer appeared brighter and bluer. This was observed as increased whiteness from L*= 84.03 with a particle size of >841 μm to L*= 90.59 with a particle size of <250 μm. Reducing the level of impurities found in the raw materials by changing the material source also improved color definition. A key finding is that the optical brightener should be applied by spraying and prepared by dispersion rather than dissolution. This improves the distribution within the granules and increases the whiteness when compared with pouring the brightener into the agglomeration vessel. Additional spray applications highlighted that brightener on the granule surface influenced whiteness more than embedded brightener. In addition, we report on the effects of the drying temperature and mixer impeller speed on powder color.
基金the Scientific Research Projects Department of Bitlis Eren University(No.BEBAP-2016.07).
文摘We examined the applicability of the pumice aggregate on the concrete formed by considering the reactive powder concrete mixture ratios, for the rigid superstructure concrete road pavement and building construction. The natural pumice aggregate in fibrous and non-fibrous concrete samples was used in the production of concrete by fracturing in 0.1-0.6 mm dimensions in rotor mill. The concreted formed in this way is named after the pumice powder concrete(PPC). The PPC samples produced were taken 7 days as 20 ℃ standard water cure, 28 days as 20 ℃ standard cure and 9 different types of combined cures. The combined cures were applied different temperatures in different durations. PPC samples were subjected to some pressure and flexural tests at the end of the standard water and combined cures. The highest compressive and flexural strengths of PPC samples were obtained after the combined cures: 3 days in 20 ℃ as standard water curing + 2 days in 180 ℃ in drying-oven. The highest compressive strength of PPC samples without any fiber was found to be 47.27 MPa, as for the highest flexural strength, it is found to be 5.23 MPa, in the end of the study. The highest compressive strength of fibrous PPC samples was 51.12 MPa, while flexural strength was 6.57 MPa.
基金Support for this project was provided by US Department of Energy grant DE-SC0011826.
文摘This research explores the prospect of fabricating a face-centered cubic(fcc) Ni-base alloy cladding(Inconel 690) on an fcc Fe-base alloy(316 L stainless-steel) having improved mechanical properties and reduced sensitivity to corrosion through grain boundary and microstructure engineering concepts enabled by additive manufacturing(AM) utilizing electron-beam powder bed fusion(EPBF). The unique solidification and associated constitutional supercooling phenomena characteristic of EPBF promotes[100] textured and extended columnar grains having lower energy grain boundaries as opposed to random, high-angle grain boundaries, but no coherent {111} twin boundaries characteristic of conventional thermo-mechanically processed fcc metals and alloys, including Inconel 690 and 316 L stainless-steel.In addition to [100] textured grains, columnar grains were produced by EPBF fabrication of Inconel 690 claddings on 316 L stainless-steel substrates. Also, irregular 2–3 μm diameter, low energy subgrains were formed along with dislocation densities varying from 108 to 109 cm2, and a homogeneous distribution of Cr23C6 precipitates. Precipitates were formed within the grains(with 3 μm interparticle spacing),but not in the subgrain or columnar grain boundaries. These inclusive, hierarchical microstructures produced a tensile yield strength of 0.527 GPa, elongation of 21%, and Vickers microindentation hardness of 2.33 GPa for the Inconel 690 cladding in contrast to a tensile yield strength of 0.327 GPa, elongation of 53%, and Vickers microindentation hardness of 1.78 GPa, respectively for the wrought 316 L stainlesssteel substrate. Aging of both the Inconel 690 cladding and the 316 L stainless-steel substrate at 685?C for50 h precipitated Cr23C6 carbides in the Inconel 690 columnar grain boundaries, but not in the low-angle(and low energy) subgrain boundaries. In contrast, Cr23C6 carbides precipitated in the 316 L stainless-steel grain boundaries, but not in the low energy coherent {111} twin boundaries. Consequently, the Inconel6
基金by National Natural Science Foundation of China (51875310)National Key R&D Program of China (2017YFB1103300).
文摘Zn based metals have exhibited promising prospects as a structural material for biodegradable applications. Pure Zn porous scaffolds were produced by laser powder bed fusion(LPBF) based on data files of designing and CT scanning. Massive Zn evaporation during laser melting largely influenced the formation quality during LPBF of Zn metal. The metal vapor in processing chamber was blown off and suctioned out efficiently by an optimized gas circulation system. Numerical analysis was used to design and testify the performance of gas flow. The surface of scaffolds was covered with numerous particles in different sizes. Processing pores occurred near the outline contour of struts. The average grain size in width was8.5m, and the hardness was 43.8 HV. Chemical plus electrochemical polishing obtained uniform and smooth surface without processing pores, but the diameter of struts reduced to 250 αm from the design value 300 m. The poor surface quality and processing pores were resulted by the splashing particles included spatters and powders due to the recoil force of evaporation, and the horizontal movement of liquid metal due to overheating and wetting. The insufficient melting at the outline contour combined with good wetting of Zn liquid metal further increased the surface roughness and processing pores.
基金A*STAR Industrial Additive Manufacturing Facilities with the research grant number 142680088.
文摘Achieving not only high mechanical strengths but also high ductility is recently established using an additive manufacturing technique called selective laser melting. In the present study, stainless steel 304 L fully dense samples were successfully printed using the 3 D systems – ProX 300 printing machine. The ductility and tensile yield strength were almost two and three times higher compared to those of ASTM cast’s alloy. Honey comb like nano-cellular structure with different orientation was observed in the fine grains(~4μm) due to fast cooling rate. In addition, the formation of martensite phase in random grains is also a contributor to the strengths. Furthermore, negative residual stresses in the build and horizontal directions were detected and assisted further increase in the tensile strength. Fractography revealed the ductile feature of plastic deformation and the crack openings at unmelted particles or pores.
基金Shenzhen Science and Technology Innovation Commission (No. ZDSYS201703031748354)National Science Foundation of Guangdong Province (No. 2016A030313756)+1 种基金the Pico Center at SUSTech with support from the Presidential fund and Development and Reform Commission of Shenzhen Municipality (No. 2016-726)the Humboldt Research Fellowship for Experienced Researchers.
文摘One of the bottleneck issues for commercial scale-up of Ti additive manufacturing lies in high cost of raw material, i.e. the spherical Ti powder that is often made by gas atomization. In this study, we address this significant issue by way of powder modification & ball milling processing, which shows that it is possible to produce printable Ti powders based on ultra- low cost, originally unprintable hydrogenation-dehydrogenation (HDH) Ti powder. It is also presented that the as-printed Ti using the modified powder exhibits outstanding mechanical properties, showing a combination of excellent fracture strength (~895 MPa) and high ductility (~19.0% elongation).
基金partially supported by the Titanium Technologies New Zealand (TiTeNZ) Programme funded by the Ministry of Business Innovation and Employment (MBIE), New Zealand.
文摘This study determined the optimal concentration of titanium diboride (TiB2) particles for the development of in situ titanium– titanium boride (Ti–TiB) metal matrix composites (MMCs) prepared by a conventional powder metallurgy route to be used for industrial applications. The effect of concentration of TiB2 particles was studied by reinforcing TiB2 powder in different mass fractions (2wt%, 5wt%, 10wt%, and 20wt%) into pure Ti powder during the fabrication process. The MMCs were sintered at high temperatures under vacuum. The transmission electron microscopy (TEM) results revealed the formation of needle-shaped TiB whiskers, indicating that in situ reaction occurred during vacuum sintering of the powder compacts. All the composite samples had a high sintered density, and the hardness of the composites increased with an increase in the mass fraction of reinforcement. Mechanical and tribological properties such as flexural strength, impact, and wear properties were determined and found to be dependent on the mass fraction of the reinforcement. However, the mechanism for the in situ reaction needs further investigation by high-energy in situ X-ray diffraction techniques.
文摘The development and function of the third-party testing platform and the evaluation of detergent products by domestic professional third-party evaluation organizations were summarized. The evaluation methods and indexes of hand washing dish detergent and fabric detergent by different third-party evaluation organizations were also concluded. The influence of third-party evaluation on the development of detergent products in China is presented.
文摘Bi-2223 precursor powders are prepared by both oxalate co-precipitation(CP) and spray pyrolysis(SP) methods.The influence of fabrication methods on the superconducting properties of Bi-2223 tapes are systematically studied. Compared to the CP method, SP powder exhibits spherical particle before calcination and smaller particle size after calcinations with more uniform chemical composition, which leads to a lower reaction temperature during calcination process for Bi-2223 tapes. Meanwhile, the non-superconducting phases in SP powder are more uniformly distributed with smaller particle sizes. These features result in finer homogeneity of critical current in large-length of Bi-2223 tape, higher density of filaments and better texture after heat treatment. Therefore,the SP method could be considered as a better route to prepare precursor powder for large-length Bi-2223 tape fabrication.
文摘BACKGROUND Gastrointestinal (GI) bleeding is a common indication for endoscopy. For refractory cases, hemostatic powders (HP) represent “touch-free” agents. AIM To analyze short term (ST-within 72 h-) and long-term (LT-within 30 d-) success for achieving hemostasis with HP and to directly compare the two agents Hemospray (HS) and Endoclot (EC). METHODS HP was applied in 154 consecutive patients (mean age 67 years) with GI bleeding. Patients were followed up for 1 mo (mean follow-up: 3.2 mo). RESULTS Majority of applications were in upper GI tract (89%) with following bleeding sources: peptic ulcer disease (35%), esophageal varices (7%), tumor bleeding (11.7%), reflux esophagitis (8.7%), diffuse bleeding and erosions (15.3%). Overall ST success was achieved in 125 patients (81%) and LT success in 81 patients (67%). Re-bleeding occurred in 27% of all patients. In 72 patients (47%), HP was applied as a salvage hemostatic therapy, here ST and LT success were 81% and 64%, with re-bleeding in 32%. As a primary hemostatic therapy, ST and LT success were 82% and 69%, with re-bleeding occurring in 22%. HS was more frequently applied for upper GI bleeding (P = 0.04) CONCLUSION Both HP allow for effective hemostasis with no differences in ST, LT success and re-bleeding.
基金National Natural Science Foundation of China(81673821)National Natural Science Foundation of China(81774142)+1 种基金Central Level Research Institute of Public Welfare Research Funds(ZZ10-016)National TCM Clinical Research Base Business Construction Second Batch of Scientific Research Projects(JDZX2015264).
文摘OBJECTIVE: To evaluated the benefits of oral administration of arsenic-containing Qinghuang Powder(QHP)compared with decitabine for patients with high/very-high(H/VH) risk myelodysplastic syndrome(MDS) according to the Revised International Prognostic Score System. METHODS: The OS(mOS) rate, annual OS rate and progression to acute myeloid leukemia(AML) in patients with H/VH MDS treated with QHP(QHP group, n = 27) and decitabine(decitabine group, n = 20) were retrospectively analyzed. The effects of prognostic factors of age, proportion of bone marrow blast,peripheral blood cell count, karyotype and Charlson Comorbidity Index(CCI) on OS were further analyzed. RESULTS: The m OS rate of QHP group(29 months) was signi?cantly longer than that of the decitabine group(18 months)(P = 0.043). The OS rates of 1, 2, and 3 years were signi?cantly higher in the QHP group(88.9%, 59.3%, 29.6%) than that in the decitabine group(70%, 25%, and 5%)(P = 0.01). There was no signi?cant difference of 5-year OS rate between the 2 groups(P = 0.133).The effects of prognostic factors on mOS were further analyzed, and it was found that there was no signi?cant difference of m OS rate between the QHP group(29 months) and the decitabine group(21 months) in the patients with age 65 years old(P = 0.673). The mOS rate was signi?cantly longer in QHP group(28.5 months) than that in decitabine group(18 months) in the patients with age of < 65 years old(P = 0.04). The proportions of bone marrow blast cells with 10% or < 10% had no signi?cant effects on the mOS rate of patients in the 2 groups(P = 0.429, P = 0.183). In patients with HGB 80 g/L, mOS rate was signi?cantly longer in the QHP group(57 months) than that in the decitabine group(21 months)(P = 0.047), while in patients with HGB < 80 g/L, there was no signi?cant difference of mOS rate between the 2 groups(P = 0.265). In the patients with PLT < 50×10~9/L, the mOS rate was signi?cantly longer in the QHP group(33 months) than that in the decitabine group(16 months)(P = 0.028). In the patients wi
基金financially supported by the National Key R&D Program of China (No.2017YFB0703100)the National Natural Science Foundation of China (NSFC) under Grant Nos. 51822103, 51671068 and 51731009the Fundamental Research Funds for the Central Universities (No. HIT.BRETIV.201902).
文摘The improvement of mechanical properties must be achieved by designing and constructing more suitable microstructure,such as hierarchical microstructure.In order to significantly enhance the creep resistance of titanium matrix composites(TMCs),two-scale network microstructure was constructed including the first-scale network(<150μm)with micro-TiB whisker(TiBw)reinforcement and the second-scale network(<30μm)with nano-Ti5Si3 reinforcement by powder metallurgy and in-situ synthesis.The results showed that the creep rate of the composite was remarkably reduced by an order of magnitude compared with the Ti6Al4V alloy at 550℃,600℃,650℃ under the stresses between 100 MPa and 350 MPa.Moreover,the rupture time of the composite was increased by 20 times,compared with that of the Ti6Al4 Valloy at 550℃/300 MPa.The superior creep resistance could be attributed to the hierarchical microstructure.The micro-TiBw reinforcement in the first-scale network boundary contributed to creep resistance primarily by blocking grain boundary sliding,while the nano-Ti5Si3 particle in the second-scale network boundary mainly by hindering phase boundary sliding.In addition,the nano-Ti5Si3 particle was dissolved,and precipitated with smaller size than the primary Ti5Si3.This phenomenon was attributed to Si element diffusion under high temperature and external stress,which could further continuously enhance the creep resistance.Finally,the creep rate during steady-state stage was significantly decreased,which manifested superior creep resistance of the composite.
文摘In this study,we developed a powder extruder system that can extrude and deposit powder mixtures to overcome the reported limitations of conventional dualpore scaffold manufacturing methods.To evaluate the extrusion and deposition capability of the powder extruder system,3D tissue-engineering scaffolds with dual-pore characteristics were fabricated with a PCL/PEO/NaCl(polycaprolactone/polyethylene oxide/sodium chloride)powder mixture.In addition,to evaluate the fabricated scaffolds,their compressive modulus,morphology,and in-vitro cell activity were assessed.Consequently,it was confirmed that the proposed powder extruder system can fabricate dual-pore scaffolds with well-interconnected pores as well as arbitrary 3D shapes shown by the fabrication of a 3D femur-shape scaffold similar to the femur model.The results of the cell proliferation and Cell Counting Kit-8(CCK-8)assays,DNA content analysis and viability assays confirm that the dual-pore scaffold fabricated by the powder extruder system improves cell attachment,proliferation,and viability.
文摘This paper presents a manufacturing cost constrained topology optimization algorithm considering the laser powder bed additive manufacturing process.Topology optimization for additive manufacturing was recently extensively studied,and many related topics have been addressed.However,metal additive manufacturing is an expensive process,and the high manufacturing cost severely hinders the widespread use of this technology.Therefore,the proposed algorithm in this research would provide an opportunity to balance the manufheturing cost while pursuing the superior structural perfonnance through topology optimization.Technically,the additive manufacturing cost model for laser powder bed-bascd process is established in this paper and real data is collected to support this model.Then,this cost model is transformed into a level set function-based expression,which is integrated into the level set topology optimization problem as a constraint.Therefore,by properly developing the sensitivity result,the metallic additive manufocturing part can be optimized with strictly constrained manufacturing cost.Effectiveness of the proposed algorithm is proved by numerical design examples.
基金Supported by National Innovation Experimental Training Planning Project for University Students (201810693018): Cultivation and Screening of Excellent Single Plants of Himalayan Endemic Plant Leycesteria formosa Wall.Project of Garden Specialty Construction in Tibet Autonomous RegionKey Science and Technology Planning Project for the Collection and Utilization of Medicinal and Ornamental Plants in Tibet.
文摘[Objectives] The study aimed to protect the good germplasm resources of Himalayan Leycesteria formosa Wall. and produce a large number of L. formosa plants used in Tibetan garden landscape.[Methods] In the intelligent solar greenhouse, the effects of different concentrations of ABT2 rooting powder on the cutting propagation of L. formosa twigs were studied, and the effects of different matrices on the growth of the cutting seedlings were analyzed.[Results] The effect of different concentrations of ABT2 rooting powder on the rooting rate of L. formosa is as follows: 200 mg/L>300 mg/L>100 mg/L, and the rooting rate is as follows: 61%>59%>57%. The rooting rate of L. formosa in the control group (CK) was 54%. The average number of roots and the average length of main root of L. formosa in the three treatments with ABT2 rooting powder were significantly different, while the average number of primary roots, average number of new branches, and average number of new leaves of L. formosa treated with 100 mg/L ABT2 rooting powder had no significant difference. There were significant differences between 200 and 300 mg/L ABT2 root powder treatments in the three growth indicators of L. formosa , and the promotion effects of 200 mg/L ABT2 rooting powder on the five indicators of L. formosa cuttings were better. The effects of different transplanting matrices on the indoor survival rate of L. formosa cutting seedlings were very obvious, and the survival rate of L. formosa cutting seedlings in matrix C was the highest, up to 96%. Different substrates had different effects on the growth of ground diameter of L. formosa cutting seedlings, and the promotion effect of matrix C was better.[Conclusions] In the rapid cutting propagation of good L. formosa , 200 mg/L ABT2 rooting powder can be selected. For indoor transplanting, matrix C (sandy soil+perlite+humus soil) should be used.
文摘Earthworms are important invertebrates that have been widely used as food and traditional medicine sources for thousands of years. Not only have researchers proven that earthworms are rich in proteins and other nutrients, they have also taken a keener interest in their unique pharmaceutical properties. Recent research has successfully discovered some beneficial functional components of earthworms due to the rapid development of biological technologies in the past decades. Therefore, earthworms could be a novel dietary supplement for human consumption. This review aims to summarize the current research about nutritional and therapeutic values of earthworms;and present a matured earthworm-derived product from Bocom Pharmaceuticals (USA) Corp as an example of its incorporation into a dietary supplement.