Nutritional and anti-nutritional components in Pachyrhizus erosus L. tuber

Tuber of Pachyrhizus erosus L., an underutilized crop, was analyzed to determine its proximate chemical composition, vitamin, mineral, and amino acid contents, and enzymatic activity. The anti-nutritional factors were also determined. The tuber had a high level of moisture, appreciable amounts of carbohydrate, crude fibre and protein and negligibly low amount of lipid. The total caloric value corresponded to 39 kcal/100 g. The amino acid profile was deficient compared to the [FAO/WHO (1973). Energy and Protein Requirements. Technical Report Series (Vol. 52, pp. 1–118). Switzerland, Geneva: WHO.] recommended pattern. The micro- and macro-nutrient analysis revealed the tuber to be potential source of potassium, sodium, phosphorus, calcium and magnesium. The tuber contained a significant amount of ascorbic acid. Thiamine, riboflavin, pyridoxine, niacin and folic acid were also detected. Very negligible contents of anti-nutrient components were observed. Comparison of these data to those of several other commonly consumed local tubers revealed that P. erosus tuber could be included in dietary formulae for man or monogastric animals, especially in those areas where carbohydrate is in short supply.     

Hafnium Diboride as a saturable absorber for Q-switched lasers

Hafnium diboride (HfB₂) is used in hypervelocity re-entry vehicles (such as intercontinental ballistic missile (ICBM) or ICBM heat shields), nuclear reactors and aerodynamic leading edges because of its strong tensile strength and high thermal resistance. HfB₂ is an ultra-high-temperature ceramic (UHTC) with a melting point of 3250°C. In this paper, we study the performance of HfB₂ as a saturable absorber in Q-switched lasers. HfB₂ has a non-saturable absorptance of 2.5?dB/µm, a saturable absorptance of 0.8?dB/µm and a saturation fluence of 12?µJ/cm². In addition, the saturation lifetime is estimated as 989.3?ps, while the recovery lifetimes are estimated as 254.9 and 22.1?ps. As a saturable absorber in our Q-switched laser, we observed pulses with durations between 880 and 2000?ns. With the addition of an acousto-optic modulator, we have observed Q-switching mode-locking, with pulses as low as 250?ns. HfB₂ can potentially work at very high power, since its damage fluence is no less than 361?mJ/cm².     

Interfacial properties of phosphate glass fibres/PLA composites: Effect of the end functionalities of oligomeric PLA coupling agents

Polylactic acid (PLA) oligomers as coupling agents have shown higher interfacial shear strength in phosphate based glass fibres/PLA composites. To influence bonding on the glass fibre surface, short chain PLA oligomers with different end groups were used as coupling agents. The low molecular weight PLA with a sodium salt terminal group, a carboxylic acid end group and also with one, two and five hydroxyl groups were produced and applied on the fibre surface through a condensation reaction. Mechanical properties of the sized fibres/PLA composites were found to be increased. XPS and TG analyses showed the presence of the coupling agents on the fibres surface. SEM analysis further confirms the presence of the agents.     

Push-out testing of SiC monofilaments with a TiC based functionally graded coating

Metal matrix composites consisting of SiC monofilaments in Ti-based matrices show great promise for aerospace applications. This work is on a novel graded coating system for SiC monofilaments used to reinforce Ti matrices. SiC Sigma monofilaments were coated with a functionally graded (FG) TiC-based coating (SiC_f/C/(Ti,C)/Ti) using close field un-balanced magnetron sputtering. The coated fibres were incorporated into Ti matrices using hot isostatic pressing. The interfacial properties of the bulk composites were then evaluated using pushout testing of thin composite samples, in order to asses the effect of the graded coating. The tests were repeated on the same samples after heat treatment. The samples were subsequently analysed using scanning electron microscopy (SEM) equipped with both secondary and backscattered electron analysis modes to identify the region of failure. The test results indicate that the FG coating offers an improvement on composite fracture toughness over the un-coated fibres by approximately 70% before heat treatment, approximately 35% after heat treatment.     

The NIP Genes in Sugar Beet: Underlying Roles in Silicon Uptake and Growth Improvement

Silicon - Silicon (Si) can stimulate plant growth and stress resistance. This study aimed at elucidating the physiological responses and molecular characterization of different NIP (nodulin 26-like...     

Brittle–ductile transition of double network hydrogels: Mechanical balance of two networks as the key factor

Tough double network (DN) hydrogels are a kind of interpenetrating network (IPN) gels with a contrasting structure; they consist of a rigid and brittle 1st network with dilute, densely cross-linked short chains and a soft and ductile 2nd network with concentrated, loosely cross-linked long chains. In this work, we focus on how the brittle gel changes into a tough one by increasing the amount of ductile component. By comparing the molecular structures of the individual first network and second network gels, we found that the true key mechanical factor that governs the brittle–ductile transition is the fracture stress ratio of the two networks, σ_f,2/σ_f,1. This ratio is related to the density ratio of elastically effective polymer strands of the two networks, ν_e,2/ν_e,1, where the inter-network topological entanglement makes dominant contribution to ν_e,2. When ν_e,2/ν_e,1 < k = 3.8−9.5, the second network fractures right after the fracture of the first network, and the gels are brittle. When ν_e,2/ν_e,1 > k, only the first network fractures. As a result, the brittle first network serves as sacrificial bonds, imparting toughness of DN gels. The study also confirms that the load transfer between the two networks is via inter-network topological entanglement. This result provides essential information to design tough materials based on the double network concept.     

Design and in vitro evaluation of interpolymer complex bound metformin sustained release tablet

Metformin hydrochloride shows high solubility and incomplete absorption in biological system. To control the release pattern of such a drug, interpolymer complexes (IPCs) have a greater advantage over the individual polymers. In view of that, hydrophilic chitosan and hydroxypropyl methylcellulose (HPMC K4M) IPCs are developed at different ratios (1 : 1, 1 : 2, 1 : 3, and 1 : 4) and characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, and X‐ray diffraction studies. Different formulations (F1–F10) are developed using individual polymers and IPCs of hydrophilic polymers. Addition of hydrophobic shellac and beeswax to IPCs extends the release rate of metformin. The physical properties and drug content values of the tablets were determined and found to be within the standard limits. Based on the results of dissolution study, it is found that formulation F10 containing 1 : 4 IPC and beeswax has shown good sustained release for a period of more than 10 h. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41018.     

Graft polycondensation of microfibrillated jute cellulose with oligo(L‐lactic acid) and its properties

In order to improve the compatibility with different polymer matrices, microfibrillated jute cellulose (MFJC) was surface grafted by oligo(l ‐lactic acid) (OLA) via graft polycondensation reaction catalyzed by Sn(Oct)₂ in toluene medium. The effects of the OLA concentration, Sn(Oct)₂ concentration, reaction time, temperature, and pressure on the progress of the graft polycondensation were investigated. Maximum grafting was found 44% at optimum reaction condition. The observation was confirmed by Fourier transform infrared spectroscopy, ¹³C‐NMR spectrometry, and X‐ray photoelectron spectroscopy. The morphology and crystalline structure of the graft copolymer (MFJC‐g‐OLA) were examined by scanning electron microscopy and wide angle X‐ray diffraction, respectively. Measurements showed that initial morphological integrity of MFJC changed due to incorporation of amorphous OLA onto MFJC surface, as a result decreases crystallinity. Extracted MFJC‐g‐OLA was also characterized by thermo‐gravimetric analysis. Results reflect the enhanced hydrophobicity and thermal stability of the MFJC as a consequence of this modification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40139.     

Study of sintering behavior of vapor forms of 1-octanethiol coated copper nanoparticles for application to ink-jet printing technology

Sub-50 nm copper nanoparticles coated with sub-5 nm 1-octanethiol layer for oxidation inhibition were examined to confirm the 1-octanethiol removal temperature as the sub-50 nm copper nanoparticles are sintered. As a result, 1-octanethiol Self-Assembled Multi-layers (SAMs) on sub-50 nm copper nanoparticles were successfully removed before sintering of copper nanoparticles so that a high density of copper line could be obtained. Finally, the line resistivity was measured and compared to verify the effect of sintering in different atmospheres. As a result, electrical resistivity of the copper pattern sintered in hydrogen atmosphere was measured at 6.96 x 10(-6) ohm-cm whereas that of the copper pattern sintered in mixed gas atmosphere was measured at 2.62 x 10(-5) ohm-cm. Thus, sintering of copper patterns was successfully done to show low electrical resistivity values. Moreover, removal of 1-octanethiol coating after sintering process was confirmed using X-ray photoelectron spectroscopy (XPS) analysis. By showing no sulfur content, XPS results indicate that 1-octanethiol is completely removed. Therefore, the vapor form of 1-octanethiol coating layers can be safely used as an oxidation inhibition layer for low temperature sintering processes and ink-jet applications.