Properties and Applications of Biodegradable Polymers

Biodegradable materials are one of the major discussable matters in the modern world. To keep and produce environment-friendly products for our daily usage the utilization of degradable materials is increasing at a high rate. The modern world wants sustainable products which will not bring about any harm to the environment. Products made from plastics are sustainable but they cause great harm to our environment due to lack of degradation property. After the end of our usage, these materials can sustain for a long time without any degradation which causes a supreme level of loss to our environment. But if we can produce products by using biodegradable raw materials, they will be degraded by the action of bio-organisms hence our environment will be protected from a great loss. So, it has become a crying need for us to use biodegradable raw materials in our products. The materials which are not biodegradable cause a great pollution especially soil pollution. To protect the world from the cruel humiliation of waste, it has become an overwhelming necessity to manufacture biodegradable products, which can quickly be degraded in the environment, from our daily useable items. The materials contain almost all the properties which are suitable for our environment. Already these materials have been using in several sectors and showing their applications for their friendly properties

Design optimisation of additively manufactured titanium lattice structures for biomedical implants

A key advantage of additive manufacturing (AM) is that it allows the fabrication of lattice structures for customised biomedical implants with high performance. This paper presents the use of statistical approaches in design optimisation of additively manufactured titanium lattice structures for biomedical implants. Design of experiments using response surface and analysis of variance were carried out to study the effect design parameters on the properties of the AM lattice structures such as ultimate compression strength, specific compressive strength, elastic modulus, and porosity. In addition, the lattice dimensions were optimized to fabricate a diamond cellular structure with properties that match human bones. The study found that the length of a diamond-shaped unit cell strut is the most significant design parameter. In particular, the porosity of the unit cell increases as the strut length increases, while it had a significant reverse effect on the specific compressive strength, elastic modulus and ultimate compression strength. On the other hands, increasing the orientation angle was found to reduce both the specific compressive strength and modulus of elasticity of the lattice structure. An optimised lattice structure with strut diameter of 0.84 mm, length of 3.29 mm and orientation angle of 47° was shown to have specific compressive strength, elastic modulus, ultimate compression strength and porosity of 37.8 kN.m/kg, 1 GPa, 49.5 MPa and 85.7%, respectively. A cellular structure with the obtained properties could be effectively applied for trabecular bones replacement surgeries

Utilization of watermelon rinds and sharlyn melon peels as a natural source of dietary fiber and antioxidants in cake

AbstractThe aim of this work was to evaluate some physical and chemical properties of watermelon rind and sharlyn melon peel powders and its utilization as partially, substituted of wheat flour at levels of 2.5%, 5.0% and 7.5% or fat at levels of 5.0%, 10% and 15% in cake making. Watermelon rinds had higher moisture, ash, fat, protein and carbohydrates 10.61%, 13.09%, 2.44%, 11.17% and 56.00%, respectively as compared to sharlyn melon peels. On the other hand, sharlyn melon peels had higher content crud fiber (29.59%) than in watermelon rinds (17.28%). The water absorption capacity (WAC) and oil absorption capacity (OAC) of sharlyn melon peels was higher than that of watermelon rinds being 7.7, 7.13 (g water/g) and 2.24, 1.65 (g oil/g), respectively. Watermelon rinds showed significantly greater free radical scavenging activity and β-carotene (39.7% and 96.44%), respectively compared to sharlyn melon peels. It contained different types of phenolic compounds, the most abundant one was 4-hydroxybenzoic acid (958.3μg/g dw) followed by vanillin (851.8μg/g dw), while the lowest phenolic compound was coumaric acid (8.8μg/g dw). On the other hand four phenolic compounds were identified in sharlyn melon peels namely, 4-hydroxybenzoic acid, vanillin, chlorgenic acid, and coumaric acid. The incorporation of WMR and SMP powders in cakes batter at all the studied levels enhanced the volume and specific volume of the baked cakes to overcome, those of the control. These materials also retard staling of cakes and inhibition the lipids oxidation and free fatty acids formation during storage. It is revealed that, substitution of 5% flour and 10% fat with watermelon rinds and sharlyn melon peels produced acceptable cakes which were not significantly different with the control

IR, 1H-NMR, UV-Vis and thermal studies on the Rhodamine 6G charge-transfer complexes

Charge-transfer (CT) complexes formed between Rhodamine 6G (Rh6G) as donor with iodine, CLA and PA as acceptors have been studied spectrophotometrically. The synthesis and characterization of Rhodamine 6G CT-complexes of iodine, [(Rh6G)2]I+.I3ˉ, chloranilic acid (CLA), [(Rh6G)(CLA)] and picric acid (PA) [(Rh6G)(PA)] were described. These complexes are readily prepared from the reaction of Rh6G with I2, CLA and PA with CHCl3 solvent. Mid and far IR, 1H-NMR, UV-Vis techniques, elemental analyses (CHN) and thermal studies, characterize the three new Rhodamine 6G charge-transfer complexes. Modified Benesi-Hildebrand method was applied to the determination of association constant and molar extinction coefficient.KEY WORDS: Rhodamine 6G, Charge transfer complexes, Picric acid, Chloranilic acid, Iodine, Thermal studies Bull. Chem. Soc. Ethiop. 2011, 25(1), 137-146

Adaptive differential pulse-coded modulation with exponential tracking

This paper first investigates a companded differential pulse-coded modulator and. derives an expression for its SNR performance. Analysis and simulations show that, the coder has superior SNR and dynamic range performance over other coders of similar complexity. The companded modulator is then extended to an adaptive differential pulse-coded modulator with high SNR and dynamic range performance, and it is shown to be BIBO stable

EVALUATION OF ANTIOXIDANT ACTIVITY OF SOME SPICES AND THEIR APPLICATION IN CROISSANT AND FILLING CREAM

Natural antioxidants have gained considerable interest in recent years for their role in preventing the auto oxidation of fats, oils and fat containing food products. In this study, six spices containing natural antioxidants were evaluated for their re-tarding fat oxidation compared to butylated hy-droxyl toluene (BHT). The yield obtained from water extract of the tested spices ranged between 20% and 50 %. Carob gave the highest yield fol-lowed by anise and cinnamon, then caraway and fennel, while ginger gave the lowest yield .The free radical scavenging activities measured by 2-diphenyl-1-picryl-hydrazyl (DPPH) were 88.08%, 81.69%, 79.62% , 78.93% , 73.06% , and 71.50 % for cinnamon, anise, carob, caraway ginger, and fennel, respectively at concentration of 2250 μg/ml. Cinnamon showed higher antioxidant ac-tivity on linoleic acid oxidation than BHT fol-lowed by anise, carob and ginger. While, fennel and caraway recorded closely antioxidant activity to that of BHT at low concentration of 100 μg/ml. Total phenolic content of the tested spices varied ranging from 11.19 to 22.95 mg as gallic acid / gm dry extract in carob and caraway, respectively. Depending upon the sensory evaluation of crois-sant containing different levels of tested spices, a concentration of 1.5% of anise, caraway fennel and cinnamon was chosen, while the chosen con-centration of ginger was 2.5% and carob was 1% for testing their effectiveness against oxidation of lipid in croissant. However, a concentration of 2% of anise, fennel, ginger and carob was chosen while, the chosen concentration of caraway and cinnamon was 1% for testing their effectiveness against oxidation of lipid in filling cream. Addi-tion of tested spices gave an excellent antioxidant effect on croissant and filling cream compared with the effect of BHT. The increase in both per-oxide and acid values after 14 and 28 days respec-tively were lower than of control and BHT. Carob, ginger, caraway and cinnamon were more effec-tive in controlling lipid oxidation during storage. In conclusion addition of tested spices as sources of effective natural antioxidants retarded lipid oxi-dation and maintain the quality of croissant and filling cream during storage

Adaptive differential pulse-coded modulation with exponential tracking

This paper first investigates a companded differential pulse-coded modulator and. derives an expression for its SNR performance. Analysis and simulations show that, the coder has superior SNR and dynamic range performance over other coders of similar complexity. The companded modulator is then extended to an adaptive differential pulse-coded modulator with high SNR and dynamic range performance, and it is shown to be BIBO stable

Adaptive predictive power control for the uplink channel in DS-CDMA cellular systems

In this paper, we analyze the conventional closed-loop power-control system. We explain that the system behaves essentially as a companded delta modulator and then derive an expression for the power-control error in terms of the channel fading, which suggests methods for reducing the error variance. This is achieved by using a prediction technique for estimating the channel-power fading profile. The prediction module is combined with several proposed schemes for closed-loop power control. The resulting architectures are shown to result in improved performance in simulations

Utilization of corn gluten meal as a protein source in great sturgeon (Huso huso) diets in growth up stage

The utilization of corn gluten meal (CGM) was evaluated as a replacement for fish meal (FM) in practical diets for beluga Huso huso in growth up stage. Four experimental diets (isonitrogenus and isocaloric , 40 % protein and 18 kj/ g diet) were formulated. Fish meal was replaced by CGM at 0%, 20%, 40% and 60% being named as CGM0, CGM20, CGM40 and CGM60, respectively. Fingerlings great sturgeon with an initial body weight of ± 78.876.94gr (mean ±SD) were reared in 12 fiberglass tanks and fed with diets for10 weeks at 20.00± 2 oC. At the end of experiment, growth performance (final weight, body increase weight, specific growth rate) of fish fed CGM20 and CGM40 were significantly higher than fish fed control diet, While feed conversion ratio were lower than fish fed CGM40 and CGM60 compared with control diet. There were not significant difference in condition factor, protein efficiency ratio and body protein in different experimental groups , but body lipid increased as dietary gluten meal increased (P<0.05). Different levels of corn gluten meal did no significantly affect Aspartat amino transferas (AST), Alanin amino transferas (ALT) and Triglyceride, but amount of cholesterol in fish fed diets CGM40 and CGM 60 were significantly lower than control diet (P<0.05). The present study revealed that CGM is a suitable source as replacement with fish meal and might be included in great sturgeon commercial diet up to 60 % with no adverse effect on nutrition efficiency, liver enzymes and biochemical parameters

On the solvability of a nonlinear functional integral equations via measure of noncompactness in

Using the technique of a suitable measure of non-compactness and the Darbo fixed point theorem, we investigate the existence of a nonlinear functional integral equation of Urysohn type in the space of Lebesgue integrable functions Lp(RN). In this space, we show that our functional-integral equation has at least one solution. Finally, an example is also discussed to indicate the natural realizations of our abstract result