A hybrid homogeneously weighted moving average control chart for process monitoring

Several modifications and enhancements to control charts in increasing the performance of small and moderate process shifts have been introduced in the quality control charting techniques. In this paper, a new hybrid control chart for monitoring process location is proposed by combining two homogeneously weighted moving average (HWMA) control charts. The hybrid homogeneously weighted moving average (HHWMA) statistic is derived using two smoothing constants λ₁ and λ₂ . The average run length (ARL) and the standard deviation of the run length (SDRL) values of the HHWMA control chart are obtained and compared with some existing control charts for monitoring small and moderate shifts in the process location. The results of study show that the HHWMA control chart outperforms the existing control charts in many situations. The application of the HHWMA chart is demonstrated using a simulated data.     

Corrosion Inhibition of Mild Steel in Aqueous HCl using Bitter Leaf and Fenugreek Seed Oils

Protection of Metals and Physical Chemistry of Surfaces - Bitter leaf and Fenugreek seed oils were extracted from their parent seed plants for use as corrosion inhibitors for mild steel in HCl....     

Evaluation of Air Oven Moisture Content Determination Procedures for Pearl Millet (Pennisetum glaucum L.)

This study evaluated moisture content determination procedures for pearl millet using seven different air oven methods. The moisture content of the pearl millet samples varied from 11–41% (wet basis). The procedures included 130°C for 1 h; 130°C for 2 h; 105°C for 5 h; 105°C for 48 h; 105°C for 72 h; 130°C for 16 h; and 130°C for 20 h. Analysis of variance revealed that at high moisture content levels above 27% (wet basis), and the mean values of the moisture content determined were not significantly different (p > 0.05). Error analysis carried out showed that the moisture content determination methods were adequate to completely remove the moisture in pearl millet with moisture less than 35% (wet basis). Regression models were developed to predict the base moisture determination method (105°C for 72 h) as a function of other procedures.     

Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O(2) (-)) and hydrogen peroxide (H(2)O(2)) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.     

Chemical composition and nutritive value of leaf protein concentrate from leucaena leucocephala

Leaf protein concentrate (LPC) was prepared from Leucaena leucocephala leaf meal (LLM). The recovery of LPC was 7.6 % and analysis showed that the LPC contained 65.91 % crude protein compared with 29.15 % of the LLM, ash content was 17.56% while levels of essential amino acids-lysine, histidine, arginine, isoleucine and leucine—were 5.57, 2.34, 5.88, 5.42 and 10.8% on a dry matter basis, respectively. The LPC had higher in-vivo digestibility than the LLM with values being 63.20 and 48.82%, respectively. The LPC diet supported growth in rats but gave lower nutritive indices than the control diet of soya bean and Guinea corn.