Defect engineering for improved photocatalytic performance of reduced lead titanate (PbTiO3) under solar light irradiation

Lead titanate (PbTiO3) nanoparticles were prepared successfully by template free hydrothermal  method. Size, crystallinity, morphology and phase determination of the nanoparticles were made by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM). FESEM results had shown that all nanoparticles were in the range between 20 to 40 nm size and found in the form of agglomerates. The average crystallite size of PbTiO3 nanoparticles was calculated to be nearly 35 nm. PbTiO3 nanoparticles were reduced by hydrogenation at high temperature to make the material active for visible light. Furthermore, optical absorbance of PbTiO3 nanoparticles was determined by applying ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. By using Davis-Mott model, the direct optical band gap of 2.65 eV was acquired. Methyl orange (MO) was used as pollutant to check the photocatalytic activity of reduced PbTiO3 nanoparticles under solar light irradiation. Photocatalytic activity of reduced PbTiO3 nanoparticles increased 2.6 times more than that of pure PbTiO3 nanoparticles for methyl orange (MO) under solar light irradiation.               KEY WORDS: Lead titanate (PbTiO3), Photocatalytic performance, Hydrothermal growth, Solar light, Irradiation Bull. Chem. Soc. Ethiop. 2019, 33(2), 373-380.DOI: https://dx.doi.org/10.4314/bcse.v33i2.1

Synthesis, structural and photo-physical studies of transition metal complexes with Mannich bases derived from 2-mercaptobenzimidazole

Two Mannich base ligands, [1-(di-n-butylamine-N-methyl)mercapto-1H-benz-imidazole] (L1) and [1-(diphenylamine-N-methyl)mercapto-1H-benzimidazole] (L2)have been synthesized and further reacted with Co(II), Ni(II), Cu(II) and Zn(II) ionsto afford their respective complexes. The progress of the reaction was monitored by thin layer chromatography. The structural elucidation of Mannich base ligands and their metal complexes was done by Fourier Transform Infrared (FTIR), UV-Visible, Nuclear Magnetic Resonance spectroscopy (1H NMR & 13C NMR) and Atomic absorption spectroscopy (AAS) / Inductively coupled plasma emission spectroscopy (ICPES). FTIR and NMR studies supported the monoanionic bidentate coordination mode of L1 and L2 while tetrahedral geometries of metal complexes were proposed on the basis of AAS/ICP, magnetic moment and electronic spectroscopic data. The synthesized compounds were also investigated for their luminescent behavior which exhibited broad emission bands indicating charge transfer nature of the involved transitions.               KEY WORDS: Metal complexes, Mannich bases, 2-Mercaptobenzimidazole, Luminescence Bull. Chem. Soc. Ethiop. 2018, 32(3), 481-490.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

Laboratory and field investigations in granular soils to correlate relative density, relative compaction and grain size

An attempt has been made to correlate relative density and relative compaction based on laboratory and field test data. In this investigation, 185 sandy soil samples were tested in the laboratory. The experimental investigations include classification tests, maximum and minimum density tests, and standard and modified Proctor and in-situ density tests. The values of the dry unit weight of these samples obtained by performing different tests fall between 14.7 kN/m(3) and 20.8 kN/m(3). Based on these results, linear and multivariate regression analyses were carried out to (a) relate relative compaction and relative density, (b) relate maximum (e(max)) and minimum void ratios (e(min)), and (c) express e(max) and e(min) in terms of median grain size (D-50) and uniformity coefficient (C-u). Experimental and predicted values varied +/- 5%, with a 95% confidence interval for the relation between relative compaction and relative density, and for other relations the variation was +/- 10%. The proposed equations were validated using a new data set which had not been used for the development of the correlations. Proposed equations were also compared with equations presented by various other researchers. Validation of the proposed equations suggests that these equations may be used for future prediction of the respective variables

Synthesis, Characterization and Biological Properties of Anions of Bivalent Transition Metal [Co(II) and Ni(II)] Complexes With Acylhydrazine Derived ONO Donor Schiff Bases

Some acylhydrazine derived ONO donor Schiff bases and their Co(II) and Ni(II) complexes have been prepared having the same metal ion (cation) but different anions. These synthesized metal(II) complexes have been characterized on the basis of their elemental analyses, magnetic moment, molar conductance, and IR and electronic spectral data. All of the Schiff base ligands function as tridentates and the deprotonated enolic form is preferred for coordination. In order to evaluate the effect of anions on the bactericidal activity, these synthesized complexes, in comparison to the uncomplexed Schiff bases have been screened against bacterial species., Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa and the results are reported

Band gap engineering for improved photocatalytic performance of CuS/TiO2 composites under solar light irradiation

ABSTRACT. Nanoparticles of CuS, TiO2 and CuS/TiO2 composites were prepared by template free hydrothermal method. Prepared nanoparticles were characterized by X-ray diffraction (XRD) and electron dispersive X-ray spectroscopy to confirm the formation of nanoparticles. Field emission scanning electron microscopy (FESEM) was applied to investigate the morphology and particle size of the nanoparticles which were measured in the range of 30–40 nm. Photocatalytic performance of CuS, TiO2 and Cus/TiO2 were measured by degradation of methyl orange (MO) under solar light irradiation. Coupling of n-type TiO2 (3.2 eV) with p-type CuS (1.9 eV) showed efficient degradation of the contaminants under the solar light irradiation. Photocatalytic performance of CuS/TiO2 composite improves 1.4 times than CuS for the degradation of methyl orange (MO) under solar light irradiation.               KEY WORDS: CuS/TiO2 composites, Photocatalytic performance, Hydrothermal growth, Solar light, Irradiation Bull. Chem. Soc. Ethiop. 2019, 33(3), 561-571.        DOI: https://dx.doi.org/10.4314/bcse.v33i3.1

Cholistan and Cholistani Breed of Cattle

Cholistan, once a green and prosperous land with the source of water being the ancient Hakra River, was also the cradle of great Hakra Valley Civilization. It is sprawled at an area of 26,000 Km2, located between the latitudes 27º42´and 29º45´North and longitudes 69º52´and 75º24´East. The bioclimatic system of Cholistan falls under the category of “tropical desert” with very scanty rainfall. Geomorphologically, the soils of Cholistan are a complex blend of river alluvium and Aeolin sands. Based on topography, type of soil and vegetation, this desert is divided into two geomorphic regions: the Lesser Cholistan (the Northern 7,770 Km² region) and the Greater Cholistan (the Southern 18,130 Km² region). The primary source of water is rainfall which is utilized through natural depressions or man-made ponds called “Tobas” and “Dahars.” The secondary source is underground water which is brackish and salty and not fit for human/animal consumption. Two livestock production systems prevail under pastoralism in Cholistan viz. transhumanie and nomadic. Despite an uncertain, unpredictable rainfall, low humidity and extremes in temperatures, Cholistan has long been famous for raising different breeds of livestock, contributing a significant share to national milk, meat and wool output. The total livestock population estimated during 2006 was 12,09528, out of which 47% were cattle. Cholistani cattle are considered to be ancestor of the Sahiwal and are a thermo-tolerant, tick-resistant breed. Preliminary data on some productive and reproductive traits of Cholistani cows maintained at Govt. Livestock Station, Jugait Peer, Bahawalpur during the period 2005 to 2009 revealed the avergae values for the productive traits i.e. lactation length, lactation yield, dry period, service period and fat percentage in milk as 165 days, 1235 liters, 155 days, 121 days and 4.8%, respectively. Similarly, the average values for reproductive traits i.e. age at maturity, age at first calving, gestation period and calving interval were 1112, 1390, 278 and 422 days, respectively, which are at par with those of Sahiwal and Red Sindhi cattle. However, comprehensive data supported by research need to be analyzed to manipulate the potentials of this breed. Furthermore, gene mapping and Marker Assisted Selection (MAS) will open up new horizons to study performance traits of Cholistani cattle in detail

Anterior Tarsal Tunnel Syndrome With Thrombosed Dorsalis Pedis Artery: A Case Report

Introduction: The aanterior tarsal tunnel syndrome denotes the entrapment of the deep peroneal nerve under the inferior extensor retinaculum. Although various etiological factors have been reported to cause anterior tarsal syndrome, its occurrence with thrombosed dorsalis pedis artery has not been reported in the English literature. Case Presentation: A 40 -year-old male patient was presented with the history of persistent pain along the dorsal surface of right foot, which was aggravated with the activities. Conservative management was tried without much relief. Diagnosis of anterior tarsal tunnel syndrome was made and the patient was planned for surgery. Thrombosed dorsalis pedis artery was found along with two adjacent collateral vessels. Retinaculum was released and nerve was mobilized. Tight compartment got released. Postoperative period was uneventful. No recurrence was seen on follow-up. Conclusion: The anterior tarsal tunnel syndrome is a known disease. A high index of clinical suspicion is required while dealing with the chronic cases. A detailed history to rule out any traumatic event is necessary too. Timely investigations and surgical release give dramatic relief

Copper (II) Acylhydrazinates. Their Synthesis and Characterization

Acylhydrazine derived furanyl and thienyl Schiff bases and their Cu(II) complexes have been prepared and characterized on the basis of their physical, spectral and analytical data. The preferred enolic form of the Schiff base function as a tetradentate ligand during coordination to the metal ion yielding a square planar complex. The Schiff bases and their complexes with different anions were tested for their antibacterial activity against bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa andKlebsiella pneumonae