Polymerization of ethyl methacrylate,methyl methacrylate,and vinyl acetate using sulfonated polystyrene as the initiator

Polymerization of ethyl methacrylate (EMA) and methyl methacrylate (MMA) was achieved in glass dilatometers, at 86°C, using polystyrene sulfonate (Na⁺ and H⁺ forms) as initiators. The conversion of EMA to PEMA and MMA to PMMA increased with the time of polymerization, quantity of initiator, and size of dilatometer but decreased with volume of water. The polymer yield was higher for the Na⁺ than for the H⁺ form of the resin initiator. The average degree of polymerization increased with increase in the volume of water, but decreased with the quantity of initiator. Vinyl acetate could not be polymerized using either the Na⁺ or H⁺ forms of the polystyrene sulfonate as the initiator under the conditions of EMA or MMA polymerization.     

Further experimental evidences of the compatibility of poly(vinyl acetate) with poly(ethyl methacrylate) and its dependence on the ratio of the molecular weight of the two homopolymers

Using various fractions of poly(ethyl methacrylate) (PEMA) and poly(vinyl acetate) (PVAc) of very narrow molecular weight distribution, a very wide range of 2–120 of molecular weight ratio M¯_ν PEMA/M¯_ν PVAc, (M¯_ν)_r was obtained. Studies of some tensile mechanical properties of films of the blends produced from solution on mercury confirmed strong dependence of the improvements of PVAc properties for blend with 18% PEMA on (M¯_ν)_r, especially in the range 5 ≤ (M¯_ν)_r < 100. The density of the films of the blend was much higher than those of the individual polymers and increased monotonically with (M¯_ν)_r. Optical micrographs of the films of the blends showed interactions between the two polymers with 18% PEMA composition, which appears to be more intimate as (M¯_ν)_r increases, as further evidence of compatibility and miscibility of the two polymers.     

Application of pretreatment methods on agricultural products prior to frying: a review

Frying is one of the methods of processing foods, which imparts flavour, taste, colour and crispness in the fried foods. In spite of an increase in the demand for fried foods by consumers all over the world, the danger posed by consuming too much fat is still a challenge. Many researchers have put forward many ideas on how to reduce the oil uptake and improve the nutritional and organoleptic qualities of foods during frying. Several pretreatment techniques applied to food materials prior to frying have been investigated by researchers in a bid to reduce the oil uptake and improve the quality parameters of fried foods. Therefore, this review focuses on the various pretreatment methods and the recent novel methods like ultrasound, infrared, superheated steam drying, microwave technique and pulsed electric field applied to foods prior to frying and its effects on the qualities of fried foods. © 2017 Society of Chemical Industry     

Optimization of oil extraction from locust bean using response surface methodology

Optimization of oil extraction from locust beans (Parkia biglobosa) using central composite rotatable design of RSM was carried out. Independent variables were roasting temperature (90, 100, 110, 120, 130°C) and roasting duration (5, 10 15, 20, 25 min), while the responses were oil yield (OY), free fatty acid (FFA), color (CO), stability, anisidine value (AV), and specific gravity (SG). Data obtained from this study were analyzed using ANOVA and regression analysis. OY, FFA, CO, oil stability, AV, and SG of the oil ranged between (19.0–22.5%), (0.65–3.1%), (37.9–199.9 mg/L), (3.6–6.4%), (11.4–59.9 mg/L), (0.7–0.9), respectively. Roasting conditions significantly influenced all dependent variables at p<0.05. Coefficients of determination (R²) of the generated models ranged from 0.49 to 0.98. Optimum roasting condition was 108°C for 10 min. This gave 22.3% OY, 1.7% FFA, 54.9 mg/L CO, 4.1% stability, 16.5 mg/L AV, and 0.9 SG. Desirability of 0.8 was obtained for optimum conditions. Practical applications: Generally, African locust bean is fermented to give condiment. It has not been used for commercial oil production despite its richness in oil, but soybean with a similar oil content of about 18–20% has been used both for condiment and commercial oil production. Research into the potential of locust bean as a source of edible oil is desirable. Roasting is among pre‐treatment methods employed in vegetable oil industry. Information on degree of influence of these parameters on quantity and quality of oil recovered oil from African locust benefits both entrepreneur and researchers. Also, the developed mathematical expression for OY, FFA, CO, oil stability, AV, and SG, as influenced by roasting temperature and duration is an effective tool in predicting these parameters. The research output has both immediate and potential application.     

Sucrose Utilization for Improved Crop Yields: A Review Article

Photosynthetic carbon converted to sucrose is vital for plant growth. Sucrose acts as a signaling molecule and a primary energy source that coordinates the source and sink development. Alteration in source–sink balance halts the physiological and developmental processes of plants, since plant growth is mostly triggered when the primary assimilates in the source leaf balance with the metabolic needs of the heterotrophic sinks. To measure up with the sink organ’s metabolic needs, the improvement of photosynthetic carbon to synthesis sucrose, its remobilization, and utilization at the sink level becomes imperative. However, environmental cues that influence sucrose balance within these plant organs, limiting positive yield prospects, have also been a rising issue over the past few decades. Thus, this review discusses strategies to improve photosynthetic carbon assimilation, the pathways actively involved in the transport of sucrose from source to sink organs, and their utilization at the sink organ. We further emphasize the impact of various environmental cues on sucrose transport and utilization, and the strategic yield improvement approaches under such conditions.     

Influence of ultrasound pretreatments on diffusion coefficients,texture and colour of osmodehydrated sweet potato (Ipomea batatas)

The moisture and solute diffusivities, texture and colour of sweet potato pretreated in distilled water with ultrasound (UD), osmotic dehydration without ultrasound (OD) and osmotic dehydration with ultrasound (UOD) were investigated to determine the effects of ultrasound on osmodehydrated sweet potato. The moisture and solute diffusivities of all the pretreatments ranged from 2.89 to 4.95 × 10^?10 and 1.17 to 1.67 × 10^?10 m² s^?1, respectively. The moisture diffusivity of samples treated in UOD was significantly (P < 0.05) higher than that of OD and UD by 30.82% and 41.62%, respectively. Compared to the fresh sample, the firmness of samples treated in OD and UOD was reduced by 83.53% and 92.47%, respectively. UD increased the brightness (L*) and reduced the redness (a*) of sweet potato, while UOD enhanced the yellowness (b*) and chroma (C*) of sweet potato. The sweet potato samples treated in UOD had the highest total colour difference (ΔE).     

Genetic algorithm for effective open port selection for a web filter

As cyber security is a major challenge in the widespread deployment of the latest technologies, the importance of selecting the open ports for a given web filter cannot be overemphasized. A network administrator would want to select a combination of ports that would be most beneficial to the users and these ports would be treated as least vulnerable. However, this is not a trivial task and can be very time-consuming, O(n!), if brute force or other naïve approaches are used to select a given number of ports from 65,536 ports available. As genetic algorithms (GAs) are commonly used to obtain near-optimal solution for complex and time-consuming tasks, this paper proposes a GA for the selection of open ports for a web filter. The gene value for each port is based on the malicious issues associated with the port and the importance of the port to the client using the web filter. The proposed algorithm is implemented in Java, and the simulation results show that GA is very accurate in identifying open ports for a given web filter.     

Three-stage interaction of dimethyl phthalate,dibutyl phthalate,and poly(vinyl acetate) with poly(methyl methacrylate)

The interaction of dimethyl phthalate (DMP), n-dibutyl phthalate (DBP), and poly(vinyl acetate) (PVAc) with poly(methyl methacrylate) (PMMA) was studied. Changes in the tensile strength, elastic modulus, and percentage elongation at break of the PMMA-additive films produced were followed using the Instron testing machine. The three additives produced (1) an initial plasticization, with a decrease in tensile strength and modulus and a possible increase in elongation; (2) an antiplasticization, with accompanying increase in tensile strength and modulus and an anomalous increase in elongation; and (3) a final plasticization, with a marked decrease in tensile strength and modulus and a definite increase in elongation of PMMA. The three effects were influenced by the molecular weight of the PMMA. A spacer effect by the interposition of the molecules of the additives between those of PMMA is proposed for the initial plasticization, while for the final plasticization, a lubrication action of the plasticizers on PMMA is suggested. Antiplasticization is explained by the formation of secondary bonds between the antiplasticizer and the PMMA molecules.