Open Access Original Research Article

Numerical Analysis of Semiconductor PN Junctions Using MATLABTM

Hamid Fardi

Journal of Scientific Research and Reports, Page 84-98
DOI: 10.9734/JSRR/2015/14434

The purpose of this project is to develop a functional PN semiconductor device simulator that is modular in nature in order to allow for flexibility during programming and to allow for future development with relative ease. In addition, the program’s main goal is to provide a tool that can supplement device modeling and the standard course material covered in a basic college level introduction, semiconductor device physics, course or and numerical analysis course and to construct basic PN semiconductor devices which can be studied using standard numerical analysis techniques. A device modeling program is developed using the basic MATLAB tools necessary to understand the operation of the program and allow future developments as necessary. MATLAB’s capability and inherent nature of handling matrices and matrix operations makes this approach an excellent technique to develop numerical analysis algorithms.
The program solution will be used to examine device parameters such as carrier statistics, device potential, and internal electric fields. The device solution is compared to analytical approximations in order to further strengthen the understanding between theory and exact numerical solutions and how those solutions are obtained.

Open Access Original Research Article

Test of Host Sanction Hypothesis in Soybean Plants Co-inoculated with Nitrogen Fixing and Non-fixing Bradyrhizobium japonicum

Diana E. Marco , Chouhra Talbi, Eulogio J. Bedmar

Journal of Scientific Research and Reports, Page 99-108
DOI: 10.9734/JSRR/2015/15510

Aims: We tested the proposed mechanism for potential sanctions, that the plant would reduce viability of non-fixing rhizobia inside nodules, performing viable Bradyrhizobium japonicum counts from co-occupied and single-occupied nodules in co-inoculated soybean plants.
Study Design: Plants were co-inoculated with two strains of B. japonicum, a highly efficient nitrogen fixing wild-type strain BJD321, and the non-fixing, nifH mutant derivative A3, to produce co-occupied nodules as well as single-occupied nodules. Strain A3 lacks nitrogenase activity but shows similar infection and nodule formation levels respect to the wild-type. As the strains used are equivalent in competitive and nodulation abilities and only differ in the nitrogen fixation ability (by nitrogenase inactivation), and share the same plant, root and even nodule, we can assert that the mechanism being tested is plant host sanction, and no other proposed mechanisms like partner choice.
Place and Duration of Study: Nitrogen Metabolism Lab, Department of Soil Microbiology and Symbiotic Systems at Zaidín Experimental Station (CSIC State Agency, Granada, Spain). 2010-2011.
Methodology: Axenic seedlings of soybean (Glycine max) cultivar Williams were inoculated with 2 ml of bacterial suspension of BJD321 or A3 strains, alone or in 1:1 mixture and supplied with sterilized N free nutrient solution. Four weeks after inoculation plants of each inoculation treatment (BJD321 + A3, BJD321 only, A3 only) were harvested, nodules were counted and weighed and plated to determine rhizobial strain occupation and population. In the aerial part of plants, determinations of weight, N and C content were done.
Results: Co-inoculated plants and plants only inoculated with the BJD321 strain showed a similar nitrogen fixation since they did not differ in dry weight, total N content and total C content. Plants with different inoculation treatments (BJD321 + A3, BJD321 only and A3 only) did not differ in nodule number. In co-inoculated plants, nodule occupation did not differ from the expected among strains (about 33% BJD321 + A3, BJD321 only and A3 only), and the weight of nodules occupied by both strains, BJD321 or A3 alone did not differ. In co-inoculated plants rhizobial viability did not differ between BJD321 and A3 strains, either comparing co-occupied nodules or single-occupied nodules. Nodule size and CFU of rhizobia inside nodules were not correlated, either in co-inoculated plants or plants inoculated with BJD321 strain alone.
Conclusion: We can conclude that in the soybean-B. japonicum system, plants facing the presence of fixing and non-fixing rhizobial strains do not sanction cheating and can perform as well as plants inoculated with the fixing strain alone.

Open Access Original Research Article

Heavy Metal Concentration in the Soil and Sediment of Kotur Industrial Area Hyderabad, India

E. I. Okoyeh , N. N. Murthy , R. K. Mohan , K. A. Krishna

Journal of Scientific Research and Reports, Page 124-132
DOI: 10.9734/JSRR/2015/15858

Heavy metal accumulations in the environment are major sources of pollution and contamination. Soil samples were collected from Kotur industrial area and analysed for heavy metal concentration such as Vanadium, Chromium, Nickel, Cobalt, Copper, Zinc, Barium, Lead, Rubidium, Strontium, and Zircon using inductively coupled mass spectrometer (ICP-MS) instrument. The ranges of concentration obtained for these metals are V (60.96-111 mg/kg), Cr (68.22–141.03 mg/kg), Ni (33.18-68.74 mg/kg), Co (10.16-17.67 mg/kg), Cu (26.35-47.59 mg/kg), Zn (49.95-183.23 mg/kg) and Pb (30.98-79.91 mg/kg). The analytical data revealed concentration above the background values. The assessment of the contamination level of the area was based on geoacummulation index (Igeo), enrichment factor (EF) and anthropogenic input. The result also showed enrichment associated with anthropogenic input for the heavy metals such as Cr, Ni, Pb, and Cu in the study area. The calculated Igeo values ranges from 1.19 to 1.43. The EF values for Cr, Ni and Pb range from 0.80 to 3.08, 0.68 to 3.07 and 0.82 to 20.6 respectively indicating moderate enrichment. The coefficient values of 0.90, 0.66, 0.62 and 0.58 observed between V and Co, Cu and between Pb with Y and Zr indicate input from similar sources.

Open Access Original Research Article

Open Access Original Research Article

Novel Edible Coating of Fresh-cut Fruits: Application to Prevent Calcium and Vitamin D Deficiencies in Children

Rosa Raybaudi-Massilia, Florangel Vásquez, Ana María Reyes, Graciela Troncone, María Soledad Tapia

Journal of Scientific Research and Reports, Page 142-156
DOI: 10.9734/JSRR/2015/15964

Aims: To enrich fresh-cut tropical fruits such s papaya, guava and banana with calcium and Vitamin D by applying based-alginate edible coatings, and to evaluate its adequacy levels in the daily requirements of children in school age, and as well as, to study both their physicochemical and microbiological stability during storage.
Study Design: Analysis of variance (ANOVA) with multiple range test (MRT) applying the Fisher´s method of the least significant difference (LSD) were used to determine significant statistically differences (P < 0.05) for physicochemical and sensory properties. Microbiological behavior and shelf-life were modeled by the modified Gompertz’s equation.
Methodology: Each fresh-cut fruit was dipped in a solution of sodium alginate (2%) enriched with vitamin D (0.0002%), then drained and dipped in another calcium lactate solution (8%) and ascorbic acid (2%; only added in the case of bananas). Finally, the samples were dried, packaged and stored at 5°C for 15 days until analysis. Calcium was determined by the volumetric method of permanganometry. Vitamin D was determined by the method of high performance liquid chromatography (HPLC). Physicochemical (titratable acidity, soluble solids, pH, firmness and color) and microbiological (mesophiles, psychrophiles, molds and yeasts counts) analyses were conducted by standard methods. Sensory analysis was performed in 60 children using a hedonic scale based on gestures.
Results: The results showed that the enrichment of fresh-cut fruit with vitamin D and calcium provides a contribution of 32-50% of the daily requirement of calcium and 83.2% of the daily requirement of vitamin D recommended for children in school age. An extended microbiological and physicochemical shelf-life was reached with those coated fresh-cut fruits in comparison with uncoated fresh-cut fruits. Sensory evaluation showed that coated fresh-cut fruits and enriched with calcium and vitamin D were well accepted by children.
Conclusion: The consumption of fresh-cut fruits coated with enriched edible coatings could be a novel alternative to prevent deficiencies of calcium and vitamin D in children allergic to milk or lactose intolerant.

Open Access Original Research Article

Heavy Metals Pollution of Water and Sediment in Mada River, Nigeria

Tukura Bitrus Wokhe

Journal of Scientific Research and Reports, Page 157-164
DOI: 10.9734/JSRR/2015/14803

Sediment acts as a sink for heavy metals, which may be remobilized into the water column. The research was carried out to assess seasonal distribution and impact of heavy metals (Zn, Mn, Ni, Fe, Cu, Cr, Cd) concentrations in sediment on the overlying water. Water and bed sediment samples were collected from Mada River during rainy and dry seasons and analyzed for the heavy metal concentrations, using atomic absorption spectrophotometer (AAS). Metal levels in water were higher during the dry season, except for the decrease in Fe (3.79±0.94 mg/L) and Mn (0.20±0.12 mg/L) concentrations. Metal levels in sediment decreased during the dry season, however, Zn (0.25±0.02 mg/kg) and Ni (0.025±0.02 mg/kg) showed an increase in concentrations. Metal levels were higher in water and sediment during dry and rainy seasons respectively. Sediment contained higher metal concentrations compared to water. Partition coefficients (Kd) values during the dry season were less than 1 except for Mn (1.35), but greater than 1 during rainy season, excluding Zn (0.39) and Ni (0.77). Correlations between metal concentrations in sediment and water were positively strong for Cu (0.7825) and Mn (0.9428). Cr, Fe and Mn levels in water and sediment were significantly different (P = .05) for both seasons. Remobilization of metals from sediment surfaces onto overlying water might account for the low Kd values and higher metal levels in water during the dry season.

Open Access Original Research Article

Fully Implicit Hybrid Block –Predictor Corrector Method for the Numerical Integration of y″' = f(x, y, y', y''), y(xο)= ηο, y'(xο) = η1, y''(xο) = η3

Bolarinwa Bolaji

Journal of Scientific Research and Reports, Page 165-171
DOI: 10.9734/JSRR/2015/14822

A fully implicit hybrid Block- Predictor Corrector method for the numerical integration of initial value problems of third order ordinary differential equations is presented in this paper. We adopted the approach of collocation approximation in the derivation of the scheme to generate a scheme with continuous coefficients, from where additional schemes were developed. The implementation strategy involves combination of the main scheme and other additional schemes as simultaneous Integrator to initial value problems of third order ordinary differential equations. Properties analysis of the block method showed that it is consistent, convergent, zero stable and absolutely stable. Numerical examples were given.

Open Access Review Article

Literature Review of 3D Vibration Control in Rotors of Turbo-Generators

Sunday Okerekehe Okpighe

Journal of Scientific Research and Reports, Page 109-123
DOI: 10.9734/JSRR/2015/12203

Review of 3D vibration control on turbo-generators is reported. Vibration has been identified as the symptoms of likely deadly and life threatening potential problems affecting Turbo-generators which eventually lead to their degradation. The causes and consequences of vibration in rotors of turbo-generators have been identified. The methods and instruments for measuring and evaluating the vibrations have been enumerated. Decision Criteria for identifying excessive vibration (that is jump-out-of-control) has been specified. The Risk Based Inspection (RBI) and Reliability Centred Maintenance (RCM) have been identified as veritable tools that ensure the Integrity Operating Window of the Turbo-generators.