|Author(s): Hana Khazal, Hussain. J. Mohammed|
|Pages: 1-7||Paper ID:143104-5959-IJCEE-IJENS||Published: August, 2014|
Abstract:A spectrophotometric method was developed for the determination of Cu(II). The method was based on the formation of Fe (II), Ni(II) 2-[(4-antipyl azo )]orcinol(APAO) complex. The complex have been characterized by spectroscopic methods such as UV-Visible ,FT-IR,molar conductivity measurements ,melting points . The maximum absorbance of complexe is at 474 nm with molar absoptivity of (0.55x104) L.mol-1.cm-1of Cu(II). Mole ratio of the complex which is formed between Cu(II) with APAO is 1:1 which was calculated by both the mole ratio and continuous variation methods. The absorbance of the complex obeys Beer?s law in the concentration range of (0.1-3.0)µg.ml for Cu(II). The stability constant of the complex under optimized conditions and at room temperature was (0.13x 107)L.mol-1 for Cu(II). This procedure can be carried out in the presence of many cations and anions in the presence or absence of the masking agents. The method was successfully applied to the determination of Cu(II) ion in analytical and fly ash samples .
|Keywords: 2-(4`- antipyriylazo ) orcinol, Copper (II) determination, spectrophotometry.|
|Full Text (.pdf) | 698 KB|
|Author(s): Nabaa karim saeed, Hussain. J. Mohammed|
|Pages: 8-15||Paper ID:143204-1818-IJCEE-IJENS||Published: August, 2014|
Abstract: A new, simple, sensitive and rapid spectrophotometric method is proposed for the determination of trace amount of palladium (II). The method is based on the formation of a 2:1 complex with 3-(4'- antipyriylazo) Salicylic acid (APASA) as a new reagent is developed. The complex has a maximum absorption at 540 nm and emax of 1.2×105 L. mol-1. cm-1. A linear correlation (0.1 – 4µg. ml-1) was found between absorbance at λmax and concentration. The accuracy and reproducibility of the determination method for various known amounts of palladium (II) were tested. The results obtained are both precise (RSD was better than0.77 % ) and accurate (relative error was better than 0.7 %). The effect of diverse ions on the determination of palladium (II) to investigate the selectivity of the method were also studied. The stability constant of the product was 3×109 L. mol-1. The proposed method was successfully applied to the analysis of synthetic mixtures and raw milk without any preliminary concentration or separation.
|Keywords: Palladium (II) determination, spectrophotometry, antipyriylazo Salicylic acid, Biological sample.|
|Full Text (.pdf) | 757 KB|
|Author(s): Inuwa Ibrahim Ibrahim, Saiva Daniel, Alkizim Ahmad|
|Pages: 16-25||Paper ID:146804-7373-IJCEE-IJENS||Published: August, 2014|
Abstract:This study investigated Nigerian indigenous contractors (NICs) involvement, performance, project planning challenges and application of project planning techniques in building project procurement systems in Nigeria. Explanatory method was used through a collective case study of building projects files. Fifteen contractors were evenly selected from a population of 69 NICs in the three geo-political zones of northern Nigeria through a Stratified random sampling technique. The documents for the case study satisfies the external and internal criticism techniques test for validity and reliability. Bloom’s hierarchy taxonomy and descriptive statistics was used to analyse data. Result reveals that NICs: are involved in both traditional and non-traditional procurement systems and their frequency of involvement is lower in the non-traditional procurement systems, underperformed in project cost and time, experience project planning challenges, and inappropriately apply project planning techniques in project procurement systems in Nigeria. This study recommends NICs to employ competent personnel, embark on continuous training, adopt project management methodology; projects clients and consultants should adhere to project management procedures; and the standard form of contract used in Nigeria should be reviewed to include a clause enforcing contractors to apply the appropriate planning techniques. Adherence to the recommendations will enhance the NICs project management performance to meet construction best practice.
|Keywords: Indigenous contractors, Nigeria, Performance, Procurement systems, Project planning.|
|Full Text (.pdf) | 459 KB|