الحاوية العلمية الوحدة: College of Engineering in Al-Kharj

CHARACTERISTICS OF K+ AND NH4+ ADSORPTION AND DESORPTION BY NATURAL BENTONITE AND ZEOLITE MINERALS MINERALS

Sat, 01 Jan 2005 00:00:00 GMT

العنوان: CHARACTERISTICS OF K+ AND NH4+ ADSORPTION AND DESORPTION BY NATURAL BENTONITE AND ZEOLITE MINERALS MINERALS

المؤلفون: M. AI-Sewailem; Falatah, A

ملخص: Zeolite mineral group is one of the tectosilicates that characterized by three dimensional framework structure with cation exchange capacity (CEC) more than phyllosilicates such as bentonite mineral. The behaviour of K+ and NH4+ with these minerals are important for increasing fertilizer efficiency of K and N.The main objective of this research was to study the sorption characteristics of K+ and NH4+by bentonite and five zeolite minerals (i.e.analcime, chabazite, phillipsite. and clinoptilolite 1 and 2). Results indicated that K sorption followed the Langmuir equation at two stages. The 1st staged at low concentrations up to 600 ppm K while the 2nd stage at 800-1600 ppm range. Binding energy (kd) at the 1st stage range from (2.7-14.66)10-2 l mg-1 and the maximum adsorption (b) in the range of 2.23-30.3 mg g-1. At the 2nd stage kd value ranged from (1.3-7.41)10-3 and b value from 18.52¬59.17 mg g-1. The highest b value was obtained with phillipsite followed by chabazite, bentonite and clinoptilolite 1 and 2. Data of sorbed K indicated that the amount of K extracted decreased with the repeat of the extraction. Phillipsite showed the highest amount of extracted K+, while the lowest amount was found with clinoptilolite. Amonium sorption data followed the Freundlich equation where bentonite, chabazite and phillipsite minerals showed more ability to adsorp NH+4. Desorption data indicated that most of the sorbed amonium was extracted in the 1 sI extraction by KCI. Analcime mineral was capable to retained NH+4in the nonexchangeable form followed by phillipsite and clinoptilolite 1 and 2. We concluded that the ability of zeolites to retain K+ and NH+4was high and there were differences between the studied minerals in sorption and desorption characteristics. On the other hand bentonite, the most common clay mineral in arid and semiarid regions, showed an intermediate ability between the studied zeolite minerals for K+ and NH+ 4 sorption.

1. Phytocidal Activity of Diclofop-methyl, Tralkoxydim and Orbencarb to Wheat Plants

Sun, 01 Jan 1995 00:00:00 GMT

العنوان: 1.Phytocidal Activity of Diclofop-methyl, Tralkoxydim and Orbencarb to Wheat Plants

المؤلفون: Tag-EL-Din; ; D. H. AL-Rajhi; M. O. Ramdoun

ملخص: Phytotoxic effects of the herbicides : Diclofop-methyl ( DCL ), Tralkoxydim (TRL) and Orbencarb ( ORB ) to wheat plants were evaluated in water culture and in potted soil . The tests included effects of several concentrations and rates of the herbicides on the seed germination ( SG ), seedling emergence ( SE ), shoot length (SL), root length ( RL ), rootlets number ( RN ), plant height ( PH ) and fresh and dry weights ( FW and DW respectively ) . The results showed that, ORB at 500 ppm caused non-significant reduction in the RN, whereas RL and SL were significantly inhibited with 0.5 and 12.5 ppm respectively . Significant reductions in each of FW and DW occurred with 0.5L ORB / ha, and its ED50 value for the SE was 1.2L/ ha . RL and SL were significantly decreased by 2.5L TRL / ha, and the respective value of each of FW and DW was 3.5 / ha . DCL affected RL at 5 ppm and each of SG and SL at 50 ppm ; its 2.5L / ha rate decreased the pH, FW and DW . In general, ORB was less effective on the SG than either TRL or DCL, and each of the latter two, at 25 ppm caused less than 50% decrease in the SG . Values of SL were gradually decreased with the increase of each of DCL and TRL concentrations, but the decrease of TRL was sharper than that of DCL, which in turn showed sharper decrease in the SL than ORB .

Tractor Repair And Maintenance In Saudi Arabia

Fri, 01 Jan 1999 00:00:00 GMT

العنوان: Tractor Repair And Maintenance In Saudi Arabia

المؤلفون: S. A. Al-Suhaibani

ملخص: Work orders for 40 tractors collected by Hail Agricultural Development Company, Saudi Arabia, were used in this study. Data for more than 1670 work orders were classified as repairs or maintenance and the relationship between tractor age and power on repair and maintenance costs was investigated. Fifty-one percent of the work orders were classified as repair work while 49% were maintenance. Repair mean total costs were significantly higher than maintenance costs. Repair and maintenance mean total costs were directly related to tractor working life (age) and tractor power.

Progressive image transmission using edge detection

Tue, 01 Jan 2002 00:00:00 GMT

العنوان: Progressive image transmission using edge detection

المؤلفون: Al-Asmari, Awad Kh.

ملخص: In this paper, a progressive image compression and transmission using edge detection scheme is adopted. The image is decomposed into two (primary and secondary) components. Canny method is adopted to detect the edges of the encoded image. These edges are replaced with a pre-designed nine basis nameplates. Then, the Macro edge detection technique is used to reduce the number of these nameplates and keep only the edges that are necessary for visual quality.Eight directional predictions and interpolation technique will be performed on the encoded edges to reconstruct the first layer of the primary component at both receiver and transmitter sides. This is called the 1st stage reconstructed image, which is subtracted from the original to have the 1st stage smooth component. Then, this process will be repeated for the 2nd and the 3rd stage components.The 3rd stage smooth component is filtered using an optimal decomposition filter and then decimated by a factor of 2. The decimated component is encoded using VQ. The decoded result of the smooth image is added to the three layers that form the primary component to have the reconstructed image. An excellent reconstructed images are found at an average of 0.179 bpp (compression ratio 45:1) and with an average PSNR of 39.45 dB. This algorithm is found to be of lower bit rate than existing image compression techniques.