Screening of lactic acid bacteria from the gut of Chrysichthys nigrodigitatus for use as probiotics in aquaculture production

Lactic and bacteria (LAB) namely Lactobacillus plantarum l and L. pentosus were isolated from the gut of Chrysichthys nigrodigitatus using Bergey's manual of determinative bacteriology (API- 50 CHL, BioMerieux). They are beneficial and safe organisms that improves disturbances of the indigenous microflora and host's immune system. Gut removed from fish samples were dissected and divided into 3 regions: fore gill, mid gut and hind gut. Lactobacillus plantarum l and L. pentosus were isolated from these regions using MRS (de Man, Rogosa and Sharpe) agar and broth after subsequent culture and sub culture to obtain discrete colonies. They were characterized as gram-positive, non-motile, catalase negative and non-sporulating bacteria

Process modeling and optimization of magnetic field pretreatment of sweet pepper and fluted pumpkin leaf

Modeling and optimization of magnetic field (MF) pretreatment of sweet pepper (SP) and fluted pumpkin leaf (FPL) were done with Response Surface Methodology. Three pretreatment factors combined were: types of MF (static, pulse and alternating), MF strength (5 - 30 mT) and pretreatment time (5 - 25 min). All the MF pretreated, control (blanched) and fresh samples were dried at 50 ˚C and analyzed for fibre, vitamin C, potassium, microbial load and colour; data obtained were used for modeling and optimization of the process. Results showed that the selected 30 developed model equations reliably described the characteristics of the process with adequate precision values of greater than four (4) and significant probability values (P ≤ 0.05) in all cases. The best optimized process conditions for the MF pretreatment process are Static MF at 14.31 mT magnetic field strength and 16.40 min pretreatment time for SP and Alternating MF at 10.42 mT magnetic field strength and 9.96 min pretreatment time for FPL. Magnetic field (non-thermal) pretreatment was able to achieve all the optimization goals better than blanching (thermal) pretreatment

Mathematical Modeling of Sun and Solar Drying Kinetics of Fermented Cocoa Beans

In this study, thin layer drying experiments were conducted to compute drying characteristics of fermented cocoa beans in open sun and indirect natural convection solar dryer. The drying experiments were conducted at the same time for comparison. Three different thin layers drying of the fermented beans were examined under field conditions for Akure, Nigeria. The drying process took place only in the falling rate period. The drying curves obtained from the experimental data were fitted to thirteen (13) different thin layer mathematical models. All the models were compared according to three evaluation parameters. These include coefficient of determination (R2), Root mean square error (RMSE) and Chi-square (X2).The results showed that increasing drying air temperature resulted to shorter drying times. The Vermal et al. model was found to be the most suitable for describing the drying curve of the convective indirect solar drying process of cocoa beans with R2 = 0.9562, X2=0.0069 and RMSE=0.0067; while, the Midilli and Kucuk model, best described the drying curve of fermented cocoa beans under open sun with R2 = 0.9866, X2=0.0024 and RMSE=0.0023

Analysis of Physical and Chemical Composition of Sweet Orange (Citrus sinensis) Peels

Sweet orange is one of the most common fruits in the World. The waste generated from the fruits needs to be put into a beneficial use. In this study some physical and chemical properties of the primary waste of sweet orange was investigated. The result showed sweet orange rinds (peels) as the major waste and contains 45-50% of the total mass of sweet orange fruits. The chemical analysis showed sweet orange rinds to be rich in protein of 7.15% and crude fibre of 12.79% which can be used as ingredients in processed food. These uses will promote sustainable disposal of orange rinds

Mechanical and durability properties of recycled aggregate concrete with ternary binder system and optimized mix proportion

This study aimed to investigate the mechanical and durability properties of recycled aggregate concrete with a ternary binder system and optimized mix proportion. Two concrete batches were developed using a densified mix design approach (DMDA) to evaluate the required mix proportions. Batch I have GGBS content varied at 0%, 10%, 20%, 30%, 40% and 50% at constant w/b ratio of 0.45, while batch II concrete mix have varied water/binder ratios: 0.3, 0.35, 0.4, 0.45 and 0.5 at constant GGBS replacement level of 30%. The fine aggregate (river sand) of the two batches was blended with fly ash at optimum loose packing density (FA + Sand) and superplasticizer (SP) was incorporated in the mix at a constant level of 1.4%. A control mix comprising of natural aggregate was also developed. The results obtained showcased the feasibility of producing structural concrete with recycled aggregates using GGBS and fly ash. The mechanical and durability properties were best at 30% GGBS content and 0.35 water/binder ratio. The DMDA for mix proportion adopted for RAC contributed significantly to improving its properties when compared to NAC, especially at the optimum observed RAC mix with compressive strength of 52 MPa. Also, the mix demonstrated good permeability resistance in terms of chloride-ion ingress and capillary water absorption

Reinforced concrete deterioration caused by contaminated construction water: An overview

Over the years, there were cases of building failures in most developing countries of the world that have led to the loss of lives and property. Yet, most investigations conducted on the causes of building failures have suggested poor design, inadequate supervision, and the use of inferior materials as the factors responsible for the failures. However, not so much emphasis has been placed on concrete mixing water as a contributing factor to the failures. Therefore, this review summarizes the effect of the type and composition of mixing water on the properties of concrete. Different sources of water that can be used to mix concrete were explored, alongside with the effect on fresh and hardened properties of concrete. The fresh properties of concrete, such as setting time and slump, were examined, while the hardened properties focused on the strength and durability of the concrete. A brief statement on the available regulation and standards for mixing water was also reported. This review shows the viability of using water from different sources, such as wastewater, to mix concrete successfully. However, the treatment of some types of water might be required to ensure that excellent strength and durability properties are achieved while preventing any threat to human life and the environment. Area for future research was also suggested, which, among other procedures, could help proffer solutions to the challenge of building failures in developing countries

Effect of Storage Temperature on Some Ogi Properties

Abstract: The study aimed at investigating the effect of storage temperatures on some quality properties of Ogi putting into consideration the peculiar situation of power supply in Nigeria. Ogi was processed using traditional method and stored at different temperatures (27±3, 5 ±2, -10±3 and -20±3ºC) for a period of 12 weeks. Proximate, pH, total titrable acidity, pasting characteristics and sensory evaluation were carried out. The total titratable acidity (Lactic acid based) began to decrease as from week 2 and throughout the period of storage in ogi samples stored at ambient temperature of 27±3ºC. A similar observation was noticed in the ogi stored at 5 ±2ºC, while ogi stored at -10±3 and -20±3ºC maintained the total titrable acidity when compared with the fresh ogi. The mean values of pH were significantly different (p<0.05) in all the storage conditions, while high pH values of 3.61±0.25 and 3.65±0.05 were recorded at week 12 of ogi stored at ambient temperature and 5±2ºC respectively. There was significant difference (p<0.05) in moisture content throughout the period of storage. There was significant difference in proximate composition (p<0.05) in all the storage conditions and throughout the storage period. The peak viscosity and final viscosity of ogi stored under the ambient temperature witnessed a noticeable reduction throughout the period of storage compared with the fresh sample of ogi. Storage at 5±2,-10±3 and -20±3ºC conditions maintained the hold strength (hot paste viscosity). The range of pasting temperature for ogi samples throughout the period of storage was between 76 and 80ºC. There was no significant difference (p<0.05) in multiple comparison results of sensory evaluation and the values for consistency were 2.7 and 2.75 at weeks 8 and 10 respectively for ogi stored at ambient temperature. The acceptability results for consistency and colour showed a significant difference (p<0.05). Ogi stored at low temperatures (-10±3 and -20±3ºC) were preferred

Engineering performance of metakaolin based concrete

The sustainable development goal (SDG) 14 of the 2030 Agenda for Sustainable Development aims at protection, conservation, and management of coastal ecosystems and resources, including by strengthening their resilience, to avoid significant adverse impacts. Coastal/marine structures are exposed to aggressive environmental con- ditions, such as chloride laden environment. Deterioration of reinforced concrete structures located in a coastal/ marine setting can influence the safety, economic and sustainability aspects of the society. Hence, there is an increased need for sustainable materials with the ability to reduce the effects of chloride attack in concrete. This experimental study aims to investigate the engineering properties of metakaolin (MK) based concrete exposed to chloride attack. The investigation was conducted for different w/b ratios of 0.54–0.61. The MK, utilised as cementitious material, was varied from 0 to 20% with an increment of 5% and ages of concrete from 7 to 56 days were considered. The effects of the above-mentioned parameters on the various properties of concrete such as workability, compressive and flexural strength, durability, resistance to chloride attack and microstructure properties of the concrete samples were investigated. From the favourable strength and durability results that were observed during the experimental study (optimum compressive strength of 49.8 MPa for 10% MK and optimum flexural strength of 8.35 MPa for 5% MK), it can be concluded that MK is a feasible supplementary cementitious material for combatting chloride attack in coastal/marine concrete structures. The obtained results, in combination with the lack of carbon dioxide CO2 released during the MK manufacturing process, further highlights the positive influence of MK on improving the serviceability and sustainability states of coastal/marine structures

Mechanical and durability properties of recycled aggregate concrete with ternary binder system and optimized mix proportion

tThis study aimed to investigate the mechanical and durability properties of recycled aggre-gate concrete with a ternary binder system and optimized mix proportion. Two concretebatches were developed using a densified mix design approach (DMDA) to evaluate therequired mix proportions. Batch I have GGBS content varied at 0%, 10%, 20%, 30%, 40% and50% at constant w/b ratio of 0.45, while batch II concrete mix have varied water/binder ratios:0.3, 0.35, 0.4, 0.45 and 0.5 at constant GGBS replacement level of 30%. The fine aggregate(river sand) of the two batches was blended with fly ash at optimum loose packing density(FA + Sand) and superplasticizer (SP) was incorporated in the mix at a constant level of 1.4%.A control mix comprising of natural aggregate was also developed. The results obtainedshowcased the feasibility of producing structural concrete with recycled aggregates usingGGBS and fly ash. The mechanical and durability properties were best at 30% GGBS content and 0.35 water/binder ratio. The DMDA for mix proportion adopted for RAC contributed sig-nificantly to improving its properties when compared to NAC, especially at the optimumobserved RAC mix with compressive strength of 52 MPa. Also, the mix demonstrated goodpermeability resistance in terms of chloride-ion ingress and capillary water absorption

Effect of Drying Parameters on the Physical Properties of Extruded Fish Feed

Commercial catfish feed is sometimes manufactured through extrusion, usually are of high moisture content which cannot be stored or transported without it being damaged, hence, the need for effective drying of fish feed. Fish feed was formulated, mixed, extruded (single screw extruder), dried (mechanical convective dryer) and evaluated upon to examine the impact of the drying parameters (air drying temperature and air-drying velocity) and some physical properties of the fish feed. Five levels of drying air temperature (40 ͦC, 50 ͦC, 60 ͦC, 70 ͦC and 80 ͦC) and three levels of drying air velocity (1.0 m/s, 1.5 m/s and 2.0 m/s) were used during the drying experiments. The final moisture content reduces with increase in drying air temperature and drying air velocities. The drying temperature does not significantly affect the unit density and porosity. Bulk density reduces with increased drying air temperature and drying air velocity. The extrudate porosity increases with drying air temperature. The drying air velocities does not significantly affect the sinking velocity and porosity. The optimum floatation time is from the feed dried at 1.5 m/s drying air velocity and 80oC drying air temperature