The Experts below are selected from a list of 3759 Experts worldwide ranked by ideXlab platform

K A Khor - One of the best experts on this subject based on the ideXlab platform.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Y W Gu, P Cheang, K A Khor
    Abstract:

    Abstract Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO 2 )-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO 2 powders were heat treated at 700°C and 800°C for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO 2 -GICs. The effects of different volume percentages of HA/ZrO 2 powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO 2 -GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO 2 particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO 2 improved the mechanical properties of the HA/ZrO 2 -GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO 2 -GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO 2 -GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO 2 -GICs were found to be much better than those of HA-GICs because ZrO 2 has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO 2 does not dissolve with increasing soaking time.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Adrian U J Yap, P Cheang, K A Khor
    Abstract:

    Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.

P Cheang - One of the best experts on this subject based on the ideXlab platform.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Y W Gu, P Cheang, K A Khor
    Abstract:

    Abstract Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO 2 )-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO 2 powders were heat treated at 700°C and 800°C for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO 2 -GICs. The effects of different volume percentages of HA/ZrO 2 powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO 2 -GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO 2 particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO 2 improved the mechanical properties of the HA/ZrO 2 -GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO 2 -GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO 2 -GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO 2 -GICs were found to be much better than those of HA-GICs because ZrO 2 has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO 2 does not dissolve with increasing soaking time.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Adrian U J Yap, P Cheang, K A Khor
    Abstract:

    Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.

Y W Gu - One of the best experts on this subject based on the ideXlab platform.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Y W Gu, P Cheang, K A Khor
    Abstract:

    Abstract Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO 2 )-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO 2 powders were heat treated at 700°C and 800°C for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO 2 -GICs. The effects of different volume percentages of HA/ZrO 2 powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO 2 -GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO 2 particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO 2 improved the mechanical properties of the HA/ZrO 2 -GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO 2 -GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO 2 -GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO 2 -GICs were found to be much better than those of HA-GICs because ZrO 2 has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO 2 does not dissolve with increasing soaking time.

Adrian U J Yap - One of the best experts on this subject based on the ideXlab platform.

  • effects of incorporation of ha zro2 into glass ionomer cement gic
    Biomaterials, 2005
    Co-Authors: Adrian U J Yap, P Cheang, K A Khor
    Abstract:

    Glass ionomer cements (GICs) are a class of bioactive cements that bond directly to bone. In this paper, a new bioactive hydroxyapatite (HA)/zirconia (ZrO(2))-filled GIC composite was developed to improve the biocompatibility and bioactivity of the GICs with the surrounding bone and connective tissues. Nano-sized HA/30 wt% ZrO(2) powders were heat treated at 700 degrees Celsius and 800 degrees Celsius for 3 h to elucidate the influence of the crystallinity of composite powders on the performance of HA/ZrO(2)-GICs. The effects of different volume percentages of HA/ZrO(2) powders (4, 12, 28 and 40 vol%) substituted within GICs were investigated based on their microhardness, compressive strength and diametral tensile strength. The HA/ZrO(2)-GICs composite was soaked in distilled water for 1 day and 1 week before subjecting the samples to mechanical testing. Results showed that the glass and HA/ZrO(2) particles were distributed uniformly in the GIC matrix. The substitution of highly crystalline HA/ZrO(2) improved the mechanical properties of the HA/ZrO(2)-GICs due to the slow resorption rate for highly crystalline powders in distilled water. The mechanical properties of HA/ZrO(2)-GICs increased with increasing soak time due to the continuous formation of Aluminium Salt bridges, which improved the final strength of the cements. The compositions 4 and 12 vol% HA/ZrO(2)-GICs exhibited superior mechanical properties than the original GICs. The mechanical properties of HA/ZrO(2)-GICs were found to be much better than those of HA-GICs because ZrO(2) has the attributes of high strength, high modulus, and is significantly harder than glass and HA particles. Furthermore, ZrO(2) does not dissolve with increasing soaking time.

Augustine O. Ifelebuegu - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Aluminium Salt Dosing on Activated Sludge Settleability Indicators: A New Settleability Model Development
    Water, 2019
    Co-Authors: Peter Ojo, Augustine O. Ifelebuegu
    Abstract:

    There has been a significant rise in the use of Aluminium Salts (Al3+) for the chemical precipitation of phosphates in wastewater treatment plants due to growing stricter regulatory requirements for wastewater effluent release to the environment. The modelling of the settleability of the resultant Al3+ sludge in present engineering practice for design and optimisation are still based on conventional sludge settleability models. This paper describes a novel activated sludge settleability model which is designed to analyse the effects of Al3+ dosing on activated sludge settleability indicators, zone settling velocity (ZSV), and stirred specific volume index (SSVI). The impact of Al3+ dosing concentrations on ZSV and SSVI of full scale activated sludge plant were analysed in the laboratory over a three years’ period and the exponential form of the Vesilind equation was optimised and validated to include alum chemical dosing parameters. The proposed model equation was found to effectively describe the settleability of Al3+ dosed sludge for dosing concentrations range of 0 to 100 mg/L.

  • The Impact of Aluminium Salt Dosing for Chemical Phosphorus Removal on the Settleability of Activated Sludge
    Environments, 2018
    Co-Authors: Peter Ojo, Augustine O. Ifelebuegu
    Abstract:

    The use of metal Salts like Aluminium in the precipitation of phosphorus in activated sludge plants has increased considerably in recent years due to the need to achieve tighter discharge consents for phosphorus in treated wastewater effluent. The impact of Aluminium Salt (Al3+) dosing on the settleability of activated sludge as a function of zone settling velocity (ZSV) and stirred specific volume index (SSVI) were investigated in batch settleability tests over a three-year period. The results showed that ZSV increased with increasing dose of Aluminium Salt as SSVI decreased. This trend was observed for dosing concentrations of less than 100 mg/L. At a dose concentration >100 mg/L, the trend was reversed as ZSV decreased and SSVI increased. At dose concentrations of 100 mg/L of Al3+, the sludge settleability started to disintegrate due mainly to surface charge reversal linked to the formation of Aluminium hydroxides and the resultant disintegration of the activated sludge floc structure.