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The study has been depicted the current advances in desalination batteries considering the understanding of concept of desalination batteries. Secondary data collection method has been used in this study based on peer reviewed journals and thematic data analysis process has been conducted in this study. Seawater desalination has been conducted with the implication of desalination batteries including the different methods such as reverse osmosis, membrane process, micro grid process has been highlighted here. PBAs implication regarding the longevity of the desalination batteries also has been discussed over here. Purification of water according to the demand of water considering the increasing population has been depicted here to analyze the process of seawater desalination. Environmental sustainability along with business sustainability also has been focused by the sweater desalination including use of desalination batteries. Advantages of the desalination batteries use have been highlighted in the study to determine the objectives of the study. Keyword : Desalination Batteries, PBAs, Water

The major focus of the study is the impact of waste management policies and use of green energy sources to reduce environmental pollution in the global business market atmosphere and all the insights have been gathered from valid and authentic sources. At the beginning of the study, a brief introduction has been served over the following topic. In the following sections, the concept of waste management policies, the types of waste management policies, the benefits have been discussed with elaboration and then, the concept of green energy sources has been made in a certain manner. After the clarification of the concept, the objectives have been constructed by depending on the subject matter. The objectives which have been made are quite relevant with the subject matter. Then, the required materials and methods have been showcased. In the following study, the secondary data has been collected by following the qualitative method. After selecting the methods, the impact of waste management policies over the global business market atmosphere which helps to reduce the environmental pollution has been depicted and the use of green energy sources has been depicted in a successive manner. Also, the impact of CSR activities with the green energy sources has been discussed in an illustrated manner. Lastly, the study has been executed with a valid conclusion over the subject matter. Keyword : CSR, environmental pollution, green energy source, waste management.

Despite extensive research on CeO2 in diverse fields, studies on dielectric, conductivity behaviours due to intentional impurity-induced structural and microstructural changes are not well established. We show that structural changes arising due to Gd3+ in nano-CeO2 and the temperature affect the dielectric and conductivity characteristics. Highly crystalline nano-CeO2 and Ce1-xGdxO2-δ (GDC) (x = 0.02–0.1) are synthesized by self-sustained high-temperature synthesis. The dependence of conductivity on dopant concentration is examined over a wide-frequency (20 Hz to 10 MHz) and temperature (200–800 °C) range using a precision impedance analyzer. The conductivity reaches maximum at x = 0.06 for Ce1-xGdxO2-δ at 600 °C beyond which conductivity decreases. There is dependence of conductivity at lower frequencies, increases with increasing frequency, and gets saturated at higher frequencies. The optimum concentration (x = 0.06) found is the lowest for the Ce1-xGdxO2-δ system reported. The observed behaviour is discussed in terms of interaction between oxygen vacancies and defect associates.

A series of Ce4+ (0-25 mol%) doped ceria nanoparticles were prepared by low temperature combustion process using the fuel oxalyldihydrazide (ODH). Crystallographic information, formation of phase and micro structural details of prepared samples was obtained by using powder X-ray diffraction (PXRD) technique, Fourier transmission infrared (FTIR) spectroscope and field emission scanning electron microscope (FESEM) technique respectively. The size (10–30 nm) of self-doped ceria nanoparticles are evaluated by transmission electron microscope (TEM). PXRD studies confirm the fluorite structure of nanoceria with JCPDS card No. 034-0394. Conductivity and dielectric studies for self-doped ceria nanoparticles were performed in the applied frequency from 20 Hz to10 MHz and at different temperatures (200-560 °C). The temperature and frequency dependence of the conductivity and dielectric properties of prepared samples showed major effect of the dopant concentration. Dielectric constant and tangent loss of prepared samples decreased sharply with increasing frequency.

In this research paper, two novel (n, n) secret image sharing schemes are proposed in which all share images are used for reconstruction of secret image(s) instead of threshold number of share images. The first proposed (n, n) secret image sharing scheme shares single secret image whereas multiple secret images are used for sharing in the second proposed scheme. The random images are generated by applying circular shift operations. The share images are generated by applying Boolean Exclusive-OR (XOR) operations on random images and secret image(s). The XOR operations improve contrast and circular shift operations improve security of the secret image(s). The proposed schemes are suitable for gray-scale and color images. The experimental simulation results and comparison with existing schemes provide consistency and feasibility of proposed schemes.

This paper proposes a compact, Fork Shaped stub to enhance the isolation between 2×2 MIMO antenna in Ultra- Wide Band. The overall size of the antenna is 28×20×1.6mm3. The proposed antenna was designed with Multiple-input -multiple-output (MIMO) and operated at a frequency of 5.1GHz for Wireless Communication. This MIMO having two antenna elements placed side by side to each other. A Fork shaped stub is placed in between two antenna elements to reduce mutual coupling. This Stub reduces the electromagnetic interferences in between MIMO elements and enhances the isolation. The proposed antenna was designed with Characteristic mode analysis for a better understanding of physical insight of structure. The dominant mode of the proposed antenna can find out easily with Characteristic Mode Analysis without applying the feed and excitation. The proposed antenna maintain good isolation more than 22dB entire UWB spectrum and Envelop correlation coefficient is (ECC)

The Indian mesosphere–stratosphere–troposphere (MST) radar is the prominent atmospheric radar that provides the atmospheric movements’ information. The radar data is analyzed to obtain the wind parameter that requires the power spectral estimation. At higher altitudes, the estimation of Doppler spectrum is found to be unsatisfactory using both parametric and nonparametric methods for spectral estimation. In this article, the hyperparameter-free, weighted sparse iterative covariance-based estimation (SPICE) method has been considered. Unlike existing SPICE method, a different hyperparameter–free, weighted SPICE method has been derived using a gradient approach with different step sizes. The two versions of SPICE algorithm, i.e., SPICEa and SPICEb, are applied to the practical MST radar data collected at National Atmospheric Research Laboratory, Gadanki (13.5°N, 79.2°E). The obtained results are evaluated with the existing atmospheric data processor results which use the basic periodogram method. The proposed method shows the significant enhancement in signal-to-noise ratio even at elevated heights.

Tumor is defined as uncontrollable and indefinite growth of cells in the brain. Diagnosis should be earlier and proper treatment of tumors is essential to prevent permanent damage to the brain or even patient death. Manual detection of brain tumor from MRI images is most critical and takes more time. In this research letter a novel optimization technique has been proposed which overcome the problems of previous existing techniques.This paper presents automatic brain tumor detection, where image is segmented and classification is carried out on brain MRI images using genetic algorithm that is meta-heuristic optimization technique and support vector machine.

NB-IoT is a predominant 3GPP standard for 5G Low Power Wide Area Networks. This paper presents two significant facets of NB-IoT, namely the link power budget and effective SNR.

This paper proposes the notion of developing new algorithm for denoising of atmospheric radar signal based on Multi-band wavelet transform. The development of this method is a tool for cleaning the Doppler spectrum, detection and estimation of wind velocity parameters like zonal (U), meridional (V) and wind speed (W). The effectiveness of the proposed algorithm (Multi-Band Discrete Wavelet Transform) is demonstrated via denoising comparisons on MST radar data with existing method DWT (Discrete Wavelet Transform). This algorithm is self-consistent in detecting wind speeds at low signal-to-noise ratio (SNR) conditions i.e., at higher altitudes. The experimental results of the radar data have been validated with the global positioning system (GPS) radiosonde data.

To extract information from remotely sensed images for wide range of applications, visual analysis and interpretation are required. In this paper, the denoising of remotely sensed images based on Fast Discrete Curvelet Transform (FDCT) has been proposed. The Fast Discrete Curvelet Transform via Wrapping(WRAP) and Unequally-Spaced Fast Fourier Transform (USFFT) has been discussed. With its optimal image reconstruction capabilities, the curvelet outperforms the wavelet technique in terms of both visual quality and Peak Signal to Noise Ratio (PSNR). This paper focuses on the analysis of denoising the Linear Imaging Self Scanning Sensor III (LISS III) images, Advanced Very High Resolution Radiometer (AVHRR) images from National Oceanic and Atmospheric Administration 19 (NOAA 19), METOP satellites for the Tirupati region, Andhra Pradesh, India. Numerical illustrations demonstrated that this method is highly effective for denoising the satellite images.

In this paper, a (k, n)visual secret sharing scheme using Boolean and shift operations that provides high security to the secret image is designed. An algorithm is proposed to encode the original secret image to generate n share images using simple Boolean XOR and circular shift operations. The secret data cannot be revealed with any k − 1 or less number of share images. The security is provided to the original secret by encrypting this secret with a random image and distinct authentication id used for each share during generation of shares. The size of generated share images is same as that of original image and requires no pixel expansion. The proposed scheme eliminates security issues observed in the related techniques. Experimental results confirm the feasibility and security of the proposed technique.

Bromo-2-hydroxy-3-methoxybenzaldehyde-p-hydroxybenzoichydrazone reacts with Cu(II) forming brown coloured soluble complex in aqueous dimethyl formamide in the pH range 3.0-8.0. It has a λmax at 405 nm. Studies were carriedout at pH-5.0. The method obeys Beer's law in the range 0.317 to 3.81 μg /ml. The molar absorptivity is 1.412×10 4 L mol -1 cm -1 and Sandell's sensitivity is 0.0045μg/cm 2 . The standard deviation of the method for ten determinations of 1.59μg/m l o f Cu(II) i s 1.22×10 -3 . T h e correlation coefficient (γ) of the calibration equation of the experimental data is 0 . 9 999. The effect of various diverse ions is studied. The formula of the complex is 1:1 and its stability constant is 3.13×10 5 . Based on the above , a rapid, simple, sensitive and selective direct visible spectrophotometric method has been developed. The method developed was used for the determination of copper(II) in alloy ,fruit, leaf and biological samples. The results are in good agreement with the certified values.

The cepstrum thresholding approach for variance reduction is applied to estimate the spectrum of mesosphere-stratosphere-troposphere radar data, which are complex. Unlike in a real data case, where the cepstral values are real, for complex signals, cepstral values will be complex. We propose two different thresholding approaches: 1) applying a threshold independently for real and imaginary values of cepstral estimates and 2) threshold application to the modulus of cepstral estimates. Reductions of the total variance of the estimated spectra using the aforementioned two threshold approaches have been tested with simulated data. Finally, the algorithm has been applied to the practical atmospheric radar data to estimate the wind parameters through the computation of Doppler shift. Results have been validated using simultaneous Global Positioning System sonde data.

A rapid and sensitive spectrophotometric method is developed for the determination of Copper (II) in aqueous DMF medium. The metal ion forms a light greenish yellow coloured complex with 5-bromo salicylaldehyde thiosemicar- bazone (5-BSAT) in acidic medium. The complex shows absorption maximum at 390nm. Beer's law is obeyed in the range 0.31 - 6.35 � gml -1 of Copper (II). The molar absorptivity (� ) and Sandell's sensitivity are found to be 1.08 X 10 4 l mole -1 cm -1 and 0.062 � gcm -2 respectively. A method for the determination of copper by third derivative spectrophotome- try is also proposed. The methods have been employed successfully for the determination of copper in grape leaves and aluminum based alloy samples.

The analytical properties of 1-phenyl-1,2-propanedione-2-oxime thiosemi-carbazone (PPDOT) are described for the first time. The reagent gives colour reactions with copper(II) and nickel(II) in sodium acetate-acetic acid buffer medium. The copper complex shows maximum absorbance at 465 nm while the nickel complex at 395 nm. Therefore, these colour reactions have been advantageously used for the simultaneous spectrophotometric determination of copper(II) and nickel(II) in synthetic mixture and also in edible oils and seeds.

A novel, sensitive and highly selective first derivative spectrophotometric method is proposed for the determination of vanadium(V) and iron(III) metal ions separately and simultaneously in a mixture. 2-Hydroxy-1-naphthaldehyde benzoylhydrazone (OHNABH) reacts with vanadium(V) and iron(III) in sodium acetate–acetic acid buffer medium (pH 5.0) forming yellow and yellowish brown colored soluble complexes, respectively. The first derivative curves of these colored solutions show maximum derivative amplitudes at 465 nm (V(V)) and 540 nm (Fe(III)) obeying Beer's law in the range 0.12–2.50 μg ml–1 and 0.14–4.20 μg ml–1, respectively. Large number of foreign ions do not interfere in the present method. A very simple and accurate simultaneous first derivative method is also reported for the determination of V(V) and Fe(III) in mixtures without solving simultaneous equations. The method is applied for the analysis of various natural samples, food and biological materials.

Mo-doped zinc oxide layers (MZO) have been prepared on cleaned glass substrates by chemical spray pyrolysis technique by varying Mo-doping concentration in the range, 0 – 5 at. %. The X-ray diffraction studies revealed that all the as prepared layers were polycrystalline in nature and exhibited wurtzite structure. The layers prepared with lower Mo-doping concentration ( 2 at. %), the films showed the (002) plane as the dominant peak. The optical analysis indicated that all the layers had an average optical transmittance of 80% in the visible region and the evaluated band gap varied in the range, 3.28 - 3.50 eV.

A simple and sensitive spectrophotometric method is developed for the determination of titanium in aqueous medium. The metal ion forms a reddish brown coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 1-7. The complex shows two absorption maxima, one at 430 nm and the other at 500 nm. The reagent shows appreciable absorbance of 430 nm and negligible absorbance at 500 nm at pH 1.5. Beer's law is obeyed in the range 0.09 to 2.15 mug ml(-1) of titanium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 1.35 x 10(4) 1 mol(-1) cm(-1) and 0.0049 mug cm(-2), respectively. A method for the determination of titanium by first-order derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of titanium in several alloy and steel samples.

This paper discusses the application of complex wavelet transform (CWT) which has significant advantages over real wavelet transform. CWT is a form of discrete wavelet transform, which generates complex coefficients by using a dual tree of wavelet filters to obtain their real and imaginary parts. In this paper we implement Selesnick's idea of dual tree complex wavelet transform where it can be formulated for standard wavelet filters without special filter design. We examine the behavior of 1 dimensional signal and implement the method for the analysis and synthesis of signal in frequency domain. Analysis and synthesis of a signal is performed on a test signal to verify the CWT application on 1D signal. The same is implemented for the MST radar signal. In this paper, CWT with custom thresholding algorithm is proposed for cleaning the spectrum. The proposed algorithm is self-consistent in detecting wind speeds up to a height of 20 km, in contrast to existing methods, which estimates the spectrum manually and failed at higher altitudes.

Rain attenuation studies especially in tropical countries assume significance due to sparse measurements and variability in rain rates and drop size distributions. Conventional techniques are not very significant in dealing with the attenuation due to melting layer and vertical structure of rainfall. The MST radar located at Gadanki, India, is an excellent state of the art system for atmospheric studies. Earlier studies have demonstrated that VHF radars like MST can also be used for precipitation studies. The VHF Radar operating at 53 MHz with a peak power of 2.5 MW is able to provide details of melting layer and drop fall velocities. However, identification of precipitation echo from the clear echo is quite challenging, as 53 MHz is not attenuated by rain. Nevertheless studies have clearly demonstrated in identifying the two echoes. Present Paper deals with new algorithms based on the wavelet analysis techniques (time series data (I & Q)) to deal with the problem. The technique has been used for SNR impr...

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, Andhra Pradesh, India Manuscript received 1 April 2004, revised 27 October 2005, accepted 28 November 2005 A simple and sensitive spectrophotometric method has been developed for the determination of nickel(ll) in aqueous medium.The metal ion forms an yellow coloured soluble complex with 2,4-dihydroxy benzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) at pH 6.0 with λmax at 400 nm. Beer's law is obeyed in the range of 0.059-1.17 μg ml-1 of NiII.The molar absorptivity and the Sandell's sensitivity of the method are 4.00 x 104 L mol-1 cm-1 and 0.0015 μg cm-2 respectively. The interference of various diverse ions has been studied.The complex has a 1 : 1 [NiII : 2,4-DHBINH] stoichiometry. A method for the determination of nickel(II) by first order derivative spectrophotometry has also been proposed. &nbsp

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Manuscript received 23 April 2003, accepted 24 November 2004 A simple, sensitive and selective spectrophotometric method has heen developed for the determination of iron(lll) in aqueous solution. The metal ion forms yellowish-brown coloured, soluble complex with 2,4-dihydroxy benzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) at pH 3.0 with λmax at 400 nm. Beer's law is obeyed in the range 0.07-2.20 µg/ml-1 of FeIII. The molar absorptivity and the Sandell's sensitivity of the method are 1.75 ± 0.025 x 104 L mol-1 cm-1 and 0.0034 µg cm2 at 400 nm respectively. The interference of various ions has been studied. The complex has a 1 : 1 [FeIII : 2,4-DHBINH] stoichiometry. A method for the determination of FeIII by first order derivative spectrophotometry has also been proposed.

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Manuscript received 25 March 2003. revised 6 February 2004. accepted 18 March 2004 A first order derivative spectrophotometric method is employed for the determination of molybdenum(VI) and simultaneous determination of molybdenum(VI) and titanium(IV). Molybdenum(VI) gives a golden yellow colour with 2,4-dihydroxy benzaldehyde isonicotinoyl hydrazone (DHBINH)' in the pH range 1-3. The first derivative spectrum shows maximum amplitude at 490 nm. Beer's law is obeyed the range 0.19 to 6.0 µg-ml-1 of MoVI at 495.5 nmwhere there is no interference from TiIV. Molybdenum(Vl) and titanium( IV) are determined simultaneously by measuring the derivative amplitudes at 495.5 nm and 580 nm in the concentration ranges 0.2 to 6.0 µg ml-1 and 0.05 to 2.40 µg ml-1 respectively, without using simultaneous equations. The method is applied for the analysis of alloy and steel samples for the molybdenum and titanium content with good accuracy.

Department of Chemistry, Jawaharlal Nehru Technological University, College of Engineering, Anantapur-515 002, India Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Fax : 91-08554-29043 Manuscript received 18 December 2001, revised 17 March 2003, accepted 7 May 2003 Diacetylmonoxime benzoyl hydrazone (DMBH) reagent has been used for the determination of Nill and Cull by spectropho­tometric method. The reagent provides intense yellow colour reaction with NiIIand Cull in basic medium. The maximum colour intensity is observed in pH range 8.0-10.0. The compositions of nickel and copper complexes of DMBH as determined by Job's and molar ratio methods are 1 : 2 and 1 : 1 (M : L) respectively. Simultaneous spectrophotometric determination of NiIIand Cull was carried out by measuring the peak-base line technique at 422.5 and 450 mm respectively. Beer's law is obeyed in the range 0.12-2.4 and 0.125-2.5 µg/mI of NiII and CuII respectively. The method is carried out without the need for employing simultaneous equation in the determination of NiII and Cull in synthetic mixtures and alloys.

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Manuscript received 16 June 1999, revised 11 February 2003, accepted 12 March 2003 A simple and sensitive spectrophotometric method is developed for the determination of cobalt in aqueous DMF medium. The metal ion forms a brown coloured complex with 5-bromosalicylaldehydethiosemicarbazone (5-BSAT) in acidic medium. The complex shows absorption maximum at 410 nm. Beer's law is obeyed in the range 0.29-5.89µg ml-1 of cobalt(ll). A method for the determination of cobalt by third derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of cobalt in steel samples.

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India E-mail : sku1@hyd.ap.nic.in Fax: 91-08554-55808 Manuscript received 20 February 2002, revised 8 July 2002, accepted 16 July 2002 Electrochemical behavior of 5-bromosalicylaldehyde isonicotinoylhydrazone has been studied at dropping mercury and glassy carbon electrodes by employing DC polarography and cyclic voltammetry in Britton-Robinson buffers (pH 2-10). The compound exhibits two polarographic waves in solutions of pH 2-10. In cyclic voltammetric studies, the hydrazone exhibits two cathodic peaks in acid solutions (pH 4.0) and one cathodic peak in alkaline solutions (pH 8.0). The electrode reactions are attributed to the reductive cleavage of =N-N- linkage and the reduction of amide formed in the cleavage.

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Fax : 91-08554-55244 Manuscript received 7 February 2000, revised 20 February 2001, accepted 19 May 2001 2-Hydroxy-1-naphthaldehydebenzoylhydrazone (OHNABH) reacts with Vv and CuII at pH 5.0 forming respectively yellow and green coloured soluble complexes in 30% DMF. The first derivative amplitude measurements show that Beer's law is obeyed in the range 0-7.5 µg ml-1 for V at 465 nm and 0-4.5 µg ml-1 for Cu at 443 nm. The sensitivity of the method is greater than the zero order method, and foreign ions like UVI, ThIV, CrVI' which interfere in zero order method, do not interfere even in large excess. Vanadium and copper present in a mixture are simultaneously determined without solving the simultaneous equations by measuring the first derivative amplitudes at 412.6 and 430.2 nm for V and Cu, respectively. The method is applied for the determination of Cu in food materials, V in alloy steels, and both V and Cu in chromium-vanadium steel.

Department of Chemistry, Sri Krishnadevaraya University, Anantapur-515 003, India Manuscript received 23 May 1997, revised 28 December 1998, accepted 4 February 1999 2,4-Dihydroxybenzophenone benzoic hydrazone (DHBPBH) is employed as an analytical reagent for the spectrophotometric determination of copper and iron. The reagent forms 1 : 1 greenish yellow coloured complex with copper(II) at pH 4.0 and λmax 380 nm (E 1.55 x 104 dm3 mol-1 cm-1); Sandell's sensitivity 0.004 µg cm-2, and Beer's law range 0.31-2.2 µg ml-1.It results a brown coloured 2: 3 complex with iron(lll) at pH 5.0 and λmax 380 nm (E 2.8 x 104 dm3 mol-1 cm-1); Sandell's sensitivity 0.002 µg em-1 and Beer's law range 0.14-1.0 µg ml-1.The method has been applied for the determination of copper in soil and alloy samples and iron( Ill) in cement sample.

A simple and sensitive spectrophotometric method is developed for the determination of throium in aqueous medium. The metal ion forms yellow coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 2.0–8.0. The complex shows an absorption maximum at 390 nm. The absorbance of the complex is maximum at pH 5.5 Beer's law is obeyed in the range 0.30–7.00 μg/ml of thorium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 2.20· 104 l·mol−1·cm−1 and 0.0106 μg/cm−2, respectively. The interference of various ions was studied. The composition of the complex is 1:1 {Th(IV) : 2,4-DHBINH}. The first derivative spectrum of the complex shows a zero cross at 391.2 nm and maximum amplitude at 415 nm. Thus a sensitive derivative spectrophotometric method for the determination of Th(IV) is proposed.

o-Hydroxyacetophenone thiosemicarbazone has been synthesized and employed as a new reagent for the spectrophotometric determination of palladium(II), which forms two complex species with it in aqueous dimethylformamide at pH 6.0, these having 1:1 and 1:2 metal-ligand ratios. The Job and molar-ratio plots have an unusual shape that is due to the stepwise conversion of the 1:1 complex into the 1:2 species. The molar absorptivity at 370 nm is 9 × 103 l.mole−1.cm−1. Beer's law is obeyed over the range 0.42–10.6 μg/ml palladium.

A catalytic method has been developed for the determination of trace amounts of mercury(II) and silver(I) based on their catalytic effect on the rate of a ligand substitution reaction. The reaction studied involved the substitution of cyanide in hexacyanoferrate(II) by isonicotinoyl hydrazide and the reaction was monitored spectrophotometrically. Satisfactory results were obtained for the determination of mercury(II) in the range 0.12–0.48 µg ml–1 and silver(I) in the range 0.03–0.15 µg ml–1. The relative standard deviation for mercury(II) was 0.743% and for silver(I) 0.696%. The effect of foreign ions on the determination was studied.

Vanadium(IV) and vanadium(V) in the presence of 2-hydroxyacetophenone oxime were extracted quantitatively into chloroform in the pH ranges 3.6–4.5 and 2.7–4.1, respectively. The organic layer showed absorbance maxima at 345 and 350 nm for VIV and VV, respectively. Studies of the behaviour of VIV were also carried out at a wavelength of 350 nm. Vanadium(V) absorbed considerably beyond 380 nm whereas VIV had negligible absorbance in this region. The absorbance of the organic layer, for both VIV and VV, was unaltered, even after 4 d. The composition of the complexes formed was established to be 1 : 2 (metal : ligand) by Job's method. Interference studies were carried out for both VIV and VV and methods are suggested for eliminating interference by foreign ions. Both VIV and VV are extracted quantitatively at pH 4; this extraction was exploited successfully for the simultaneous determination of VIV in the range 1–3 µg ml–1 and VV in the range 1–6 µg ml–1 by measuring the absorbances at 350 and 400 nm, respectively.