Lactic acid fermentation of anthocyanin-rich sweet potato (Ipomoea batatas L.) into lacto-juice

Sweet potato (SP) is an important root crop grown all over the world and consumed as a vegetable, boiled, baked or often fermented into food and beverages. The grated SP roots [non- boiled and fully boiled (boiled in water at 100 °C for 15 min) were treated with 0.05% of commercial pectinase enzyme (Pectinex, Novoenzyme) in order to extract the juice. The fresh juice was inoculated with Lactobacillus plantarum MTCC 1407 culture at 28 ± 2 °C for 48 h to produce lacto-juice (LJ). The anova analysis of analytical data revealed that there was significant effect of boiling conditions (fully boiled and non-boiled) on pH [ F (1, 4) = 220.5, P  < 0.001), TA [ F (1, 4) = 78.89, P  < 0.01], starch [ F (1, 4) = 26.63, P  < 0.01), total sugar [ F (1, 4) = 61.36, P  < 0.01) and anthocyanin [ F (1, 4) = 32.86, P  < 0.01) but not on reducing sugar [ F (1, 4) = 2.48, P  = 0.19). Sensory evaluation rated the SP LJ acceptable based on texture, taste, aroma, flavour and after taste. LJ prepared from fully boiled roots with 10% cane sugar was most preferred by a consumer's panelist based on Linear Discriminant Analysis. Principal component analyses (PCA) reduced the seven original analytical variables to three independent components (factors), which accounted for 99.9% of the total variations. Similarly, six original sensory variables were reduced to two independent components, which accounted for 65.7% of the total variations.     

Vitamin A requirements assessed by plasma response to supplementation during pregnancy

The intestinal parasitic helminth infections of man in Bonny and Isiokpo communities were studied between May 1992 and March 1994. Of the 2008 stool samples examined from Bonny community, 503 (25.0%) were infected. 305 (26.7%) of these infections were males while 198 (22.9%) were females. Ascaris lumbricoides (24.1%) occurred most frequently, followed by Hookworms (18.0%), Trichuris trichiura (17.3%,) Strongyloides stercoralis (10.1%) and Enterobius vermicularis (0.1%). Peak infection (41.7%) was recorded for the males in (10-14) years age bracket. The use of bush as a toilet facility had the highest parasitic infection (38.3%), followed by that of shoreline (35.3%), pit (33.3%), Bucket (27.8%) and of water closet (7.5%). Degree of infection relative to source of drinking water showed that well water was associated with highest infection (43.3%) while the pipe borne water was the lowest (18.0%). From Isiokpo community 2,462 stool samples were examined for intestinal parasites 1,633 (66.3%) people were infected consisting of 862 (64.8%) males and 771 (68.2%) females. Higher parasitic infection of females in this community was attributed to the cultural and occupational factors. Frequency of occurrence of individual helminth was as follows: A-lumbricoides (64.5%), T. trichiura (59.4%), Hookworms (58.8%), S. stercoralis (25.1%), Hymenolepsis nana (2.9%) and E. vermicularis (0.3%). Prevalence of infection was significantly higher in Isiokpo than in Bonny because the climatic and edaphic factors were conducive to larval development and infectivity. On the contrary, the saline soil and surface water of Bonny community constituted harsh environmental conditions inimical to larval development and infectivity. Observations on parasitic infections in relation to toilet facilities and source of drinking water were similar to those made in Bonny. The study therefore demonstrated that the provision of pipe borne water and water closet facilities in rural Niger Delta communities could reduce helminth infections of man.     

Investigation of failures in stainless steel orthopaedic implant devices: pit-induced stress corrosion cracking

Journal of Materials Science Letters -     

A simple implicit scheme for stress response computation in plasticity models

In this work, the authors propose an efficient numerical method for evaluating the plastic response of a material for the applied load. Focus is confined to plasticity models using a yield surface and to small strains. The main advantage of the method is that there is no iteration need be done for the yield surface drift correction and applies a single point integration. To compute the response of a material for a particular loading, the incremental constitutive equation is derived from the plasticity model used and then it is numerically integrated. Since finite increments are used in the numerical integration procedure, computational errors crop up and accumulate causing inconsistencies in the response calculation. This is usually seen in the form of a yield surface drift. To alleviate this problem, the quantities updated have to be corrected appropriately so that the yield condition is satisfied. The authors propose a method here which corrects implicitly the quantities updated to avoid the yield surface drift. No iterations are involved. The discrete consistency condition is used in the proposed model. The authors have shown in this work that the method can be applied easily to several yield conditions and hardening rules. A numerical study is performed to evaluate the performance of the model compared to the other methods to show the efficiency of this method in the response calculations for yield surface models.     

Combined influence of throughflow and Soret effect on the onset of Marangoni convection

The onset of Marangoni convection with throughflow and the Soret effect in a top-free and bottom-rigid horizontal fluid layer is studied using the normal mode method for different types of thermal and solutal boundary combinations. The bottom surface is either conducting or insulating to temperature and solute concentration perturbations. The resulting eigenvalue problem is solved exactly by assuming that stationary convection is exhibited at the neutral state. It is found that the destabilizing behavior of a small amount of throughflow described by Nield (J Fluid Mech 185:353–360, 1987) becomes more significant in the presence of Soret effect for some boundary combinations. The results are consistent with the existing results in the literature.     

Effect of salt concentration on poly (vinyl chloride)/poly (acrylonitrile) based hybrid polymer electrolytes

Hybrid, solid polymer electrolyte films consisting of poly (vinyl chloride) (PVC), poly (acrylonitrile) (PAN) and, propylene carbonate (PC) with different concentrations of LiClO₄ are prepared by means of a using solvent-casting technique. The structure and complex formation are studied by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The temperature dependence of the ionic conductivities of the polymer films is explained in terms of a free volume model. The conductivities of PVC–PAN–LiClO₄–PC complexes are determined at different salt concentrations. The highest ionic conductivity (8.35 × 10⁻⁵ S cm⁻¹) is obtained for 8 wt.% LiClO₄ in the polymer complex at 304 K. The thermal stability of the electrolyte is examined by thermogravimetric/differential thermal analysis (TG/DTA).     

Cue-based networking

In this paper we present a new approach called cue-based networking that uses hints or cues about the physical environment to optimize networked application behavior. We define the notion of cues and describe how cues can be obtained using wireless sensor networks as the underlying platform. We identify both the research and system challenges that need to be addressed to realize benefits of the approach under a target application of video delivery over IP networks. In the process, we identify key challenges of wireless sensor networks, namely timeliness and robustness. We design an adaptive algorithm that balances the tradeoff between them satisfying both timeliness and robustness requirements. Through an implementation of the video delivery application using the proposed algorithm in a real home environment, we highlight the practical benefits of the proposed approach.     

Close-range blast loading on empty recyclable metal beverage cans for use in sacrificial cladding structure

This article deals with the experimental and numerical blast study on a single empty recyclable metal beverage can. The idea is to make a macro-foam (sacrificial cladding structure) out of these cans to protect the main load bearing members of civil engineering structures from the air blast load. Close-range free air blast tests have been conducted to understand the crushing behaviour and the energy absorption of a single empty beverage can in detail. To conduct such an air blast test a special small-scale test set-up was designed and manufactured. The effect of skin plate surface area and its nature on the blast parameters is studied. Furthermore, the effect of inertia of the skin plate on the crushing performance of the beverage can is evaluated. Tests have been conducted with different plates (made of aluminium and sandwich composite materials) with different masses which represent the skin plate of the proposed sacrificial structure. The measured blast parameters from the experimental tests were compared with ConWep predicted data. Furthermore, the influence of the finite surface area of the skin plate on the clearing of the reflected pressure waves was also studied. The deformation behaviour and the corresponding energy absorption of empty beverage cans were captured. During the experimental blast tests it was observed that a part of the total reflected impulse (∼30%) was lost before it transfers to the non-sacrificial structure. Hence, in order to investigate this phenomenon Eulerian-Lagrangian coupled analyses were conducted using Hydrocodes. The results from these analyses showed that the diffraction and ground reflected pressure wave caused the loss in impulse. The results from the numerical studies have been compared and validated with the experimental results.