Enhancement the crystallization and electro-magnetic properties of BaO-Al2O3-B2O3 glass ceramics doped with Nd2O3-rare earth.

In the present study, a novel glass system containing Neodymium(III) oxide with BaO, Al2O3, and B2O3 were created via a popular melt-quenching technique. Nd2O3 were added, in different concentrations, instead of B2O3 to study its impact on the crystallization, and electro-magnetic behaviors of the prepared poly-crystalline materials. Thermal characteristics via DTA, XRD and SEM techniques were involved to explore the crystallization and structural properties. The magnetic parameters of the prepared glass-ceramics were studied by VSM measurements. As well the electric properties were also explored. BaB2O4 and Al(BO3) phases were firstly crystallized then Ba3Nd(BO3)3 phase was incompletely precipitated instead of BaB2O4 phase owing to Nd2O3 additions. As well, the internal structure was modified from coarse crystals to fine grain microstructure. The crystallization study proved that the addition of neodymium improved the crystallization process of the BaO-Al2O3-B2O3 glass system. The VSM and conductivity analysis for the crystalline materials proved that the Nd2O3/B2O3 substitutions led to an increase in the electrical and magnetic parameters of the investigated materials. The data obtained from the prepared crystalline specimen showed that these materials are with a distinct and promising ferro-electrical property for use in diverse modern applications.

XRD, FTIR and ultrasonic investigations of cadmium lead bismuthate glasses.

Cadmium lead bismuthate glasses in the system xCdO-(1-x)[0.5PbO + 0.5Bi2O3](40 mol% ≤ x ≤ 90 mol%) were successfully prepared by melt-quenching method. The structural and elastic properties have been investigated using XRD, FTIR and ultrasonic pulse-echo techniques. The XRD patterns confirmed the amorphous nature of the samples prepared. Density and ultrasonic velocity data were used to evaluate various elastic properties. Addition of CdO gave rise to decreased density and molar volume and increased elastic moduli, micro-hardness, and Debye temperature. The FTIR analysis revealed that increasing CdO content enhances the BiO6 octahedral sites at the expense of the BiO3 and PbO4 units. This results in the formation of Pb-O-Bi(6) and Bi(3)-O-Bi(6) linkages in the glass network, which stiffen the structure and improve the elastic properties. A correlation between elastic and compositional parameters was achieved on the basis of theories and approaches in the field.

Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.

Defect formation of gamma irradiated MoO3-doped borophosphate glasses.

Borophosphate glasses of the basic composition (50P2O5, 30B2O3, 20Na2O mol%) containing different doping molybdenum oxide percents (0.16-0.98) were prepared by melting and annealing method. Infrared and UV-visible absorption spectroscopic measurements before and after gamma irradiation were carried out. The base undoped borophosphate glass reveals strong UV absorption bands but with no visible bands and these UV bands are related to unavoidable trace iron impurities contaminated within the raw materials used for the preparation of this glass. The introduction of MoO3 (in doping ratio) into this glass produces an additional UV band and a broad visible band and their intensities increase with the MoO3 content. These additional bands are related to both Mo(6+) and Mo(5+) ions. The base undoped borophosphate glass shows retardation effect towards gamma irradiation. Gamma irradiation produces marked changes in the UV-visible spectra of Mo-O3-doped glasses. Such changes can be related to the production of induced defects from photochemical reactions and the generation of positive holes. Infrared absorption spectrum of the undoped borophosphate glass reveals complex vibrational bands due to the presence of both phosphate groups beside borate groups with triangular and tetrahedrally coordinated units. The introduction of MoO3 causes some limited variations in the FTIR spectra. Gamma irradiation produces minor changes in the intensities of some IR bands. Such changes are related to the changes in the bond angles and/or bond lengths of few structural groups upon irradiation while the main structural groups remain unchanged in their number and position.

Optical and infrared absorption spectra of 3d transition metal ions-doped sodium borophosphate glasses and effect of gamma irradiation.

Undoped and transition metals (3d TM) doped sodium borophosphate glasses were prepared. UV-visible absorption spectra were measured in the region 200-900nm before and after gamma irradiation. Experimental optical data indicate that the undoped sodium borophosphate glass reveals before irradiation strong and broad UV absorption and no visible bands could be identified. Such UV absorption is related to the presence of unavoidable trace iron impurities within the raw materials used for preparation of this base borophosphate glass. The TMs-doped glasses show absorption bands within the UV and/or visible regions which are characteristic to each respective TM ion in addition to the UV absorption observed from the host base glass. Infrared absorption spectra of the undoped and TMs-doped glasses reveal complex FTIR consisting of extended characteristic vibrational bands which are specific for phosphate groups as a main constituent but with the sharing of some vibrations due to the borate groups. This criterion was investigated and approved using DAT (deconvolution analysis technique). The effects of different TMs ions on the FTIR spectra are very limited due to the low doping level (0.2%) introduced in the glass composition. Gamma irradiation causes minor effect on the FTIR spectra specifically the decrease of intensities of some bands. Such behavior is related to the change of bond angles and/or bond lengths of some structural building units upon gamma irradiation.

Microstructural dependence on relevant physical-mechanical properties on SiO2-Na2O-CaO-P2O5 biological glasses.

Bioactive glasses of the system SiO2-Na2O-CaO-P2O5 have been prepared by the normal melting and annealing technique. The elastic moduli, attenuation, Vickers hardness, fracture toughness and fracture surface energy have been obtained using the known method at room temperature. The temperature dependence of elastic moduli and attenuation measurements have been extended over a wide range of temperature from 150 to 500 K. The SiO2 content dependence of velocities, attenuation, elastic moduli, and other parameters show an interesting observation at 45 wt% of SiO2 by exhibiting an anomalous behaviour. A linear relation is developed for Tg, which explores the influence of Na2O on SiO2-Na2O-CaO-P2O5 bioactive glasses. The measured hardness, fracture toughness and fracture surface energy show a linear relation with Young's modulus. It is also interesting to note that the observed results are functions of polymerisation and the number of non-bridging oxygens (NBO) prevailing in the network with change in SiO2 content. The temperature dependence of velocities, attenuation and elastic moduli show the existence of softening in the glass network structure as temperature increases.

Hypospadias repair using a modified Foley catheter (hole-end catheter).

PURPOSE: The aim of this study was to test the effectiveness of a modified Foley catheter for improving the results of hypospadias repair by decreasing the incidence of obstruction. MATERIALS AND METHODS: Seventy-two patients (age 3 to 21 years) with variable types of hypospadias were treated. Bladder drainage was performed by urethral catheter insertion. The patients were divided equally into two groups of 36 patients each, according to the type of catheter used. In the first group of patients, a Foley catheter was inserted; in the second group, a modified Foley catheter (hole-end catheter) was introduced for urine drainage. RESULTS: Fourteen patients (19.4%) required secondary surgical repair: 8 (22.2%) in the first group and 6 (16.7%) in the second group. The rate of complications was lower in the second group than in the first group (25% and 50%, respectively). In the first group, 4 patients (11.1%) had urethral catheter obstruction: one was relieved by catheter flushing using sterile normal saline and three by suprapubic diversion. In the second group, urine retention was recorded in 2 patients (5.5%) and relieved by saline wash. CONCLUSION: The hole-end catheter provides better bladder drainage with the ability to easily dislodge precipitations.