There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

A review on g-C3N4-based photocatalysts

/pdf/degradable-controlled-release-polymers-and-polymeric-1y322ha58z.pdf

Degradable Controlled-Release Polymers and Polymeric Nanoparticles: Mechanisms of Controlling Drug Release

Metals and sulphate removal from acid mine drainage in two steps via ferrite sludge and barium sulphate formation

Southern African clinoptilolite capability as an ion-exchanger with respect to Cu2+ and Co2+ was investigated in order to consider its possible application at removing metals from aqueous solutions. The column method was used in the cation-exchange processes with synthetic solution concentrations of 0.07 M (3.86 g/.), 0.33 M (19.31 g/.) and 0.66 M (38.63 g/.) of Cu2+ solution and 0.07 M (3.34 g/.), 0.33 M (16.69 g/.) and 0.66 M (33.37 g/.) of Co2+ solution. Synthetic non-mixed sulphate solutions of copper and cobalt recorded maximum cation uptakes of 79% and 63% with 0.02 M HCl-activated clinoptilolite respectively. From the Cu/Co mixed solutions, both cobalt and copper recorded a 79% uptake with 0.02 M HCl-activation. The 0.04 M HCl activation gave percentage removals of 79% and 77% for Co2+ and Cu2+ respectively. In the ion-exchange evaluation part of the study, it was found that in every concentration range, the adsorption mass ratio of clinoptilolite to metal concentration conformed to both Langmuir and Freundlich adsorption isotherms. However, the non-mixed aqueous solutions of Cu2+ and Co2+ fitted mainly the Langmuir equation. It was found that the adsorption process depends on the hydrated radius of the cation being exchanged, the concentration of the acid that activates the clinoptilolite and the concentration of the targeted cation in solution.

/pdf/removal-of-copper-and-cobalt-from-aqueous-solutions-using-3ns5w8hb0d.pdf

Removal of copper and cobalt from aqueous solutions using natural clinoptilolite

The problem of limited water supply in the Vhembe District (Limpopo Province, South Africa) is exacerbated by a preponderance of dissolved salts, which cause disagreeable taste and odour in the water as reported by the communities using this water for drinking. The water treatment plant that supplies the treated water to the communities in the District sources this raw water from the Nandoni Dam at the Luvuvhu river catchment. There are no scientific studies that have been reported in the literature that focused on determining the levels of water salinity from various water sources in the municipalities of the District. Water samples from various sites across the Nandoni Dam, a primary source of domestic water supply in the region, were collected through each season over a period of twelve months in order to ascertain the concentrations of dissolved salts in the dam. Onsite analyses of the water samples were conducted using the YSI ProDSS multimeter, while the laboratory water analyses were conducted using the spectroquant and atomic absorption spectrometers. Although salinity tests seem to indicate that the water sampled across most of the Nandoni Dam is brackish during all seasons of the year with the highest being 750 mg/L, water samples from the dam mid-outlet and the treatment plant are slightly below the World Health Organization (WHO) brackish water bracket of 500 mg/L with unfavourable taste for drinking. Results from this study indicate that the water sourced from the Nandoni Dam is not suitable for human consumption and therefore requires integrated water resource management, as well as robust and cost-effective water desalination treatment.

https://biblio.ugent.be/publication/8569778/file/8589290.pdf

Spectroscopic Determination of Water Salinity in Brackish Surface Water in Nandoni Dam, at Vhembe District, Limpopo Province, South Africa

Occurrence and spatial distribution of statins, fibrates and their metabolites in aquatic environments

A series of S/Gd3+-codoped TiO2 photocatalysts were synthesized by a modified sol-gel method. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM)/energy-dispersive spectroscopy (EDS). Laboratory experiments with Indigo Carmine chosen as a model for organic pollutants were used to evaluate the photocatalytic performance of S/Gd3+-codoped TiO2 under visible-light with varying concentrations of Gd3+ ions in the host material. XRD and Raman results confirmed the existence of anatase phase TiO2 with particle size ranging from 5 to 12 nm. Codoping has exerted a great influence on the optical responses along with red shift in the absorption edge. S/Gd3+-codoped TiO2 showed significant visible-light induced photocatalytic activity towards Indigo Carmine dye compared with S-TiO2 or commercial TiO2. TiO2-S/Gd3+ (0.6% Gd3+) degraded the dye (ka = 5.6 × 10−2 min−1) completely in 50 min.

/pdf/sulfur-gadolinium-codoped-tio-2-nanoparticles-for-enhanced-1l0kb6im51.pdf

Bhekie B. Mamba

Papers

Metals and sulphate removal from acid mine drainage in two steps via ferrite sludge and barium sulphate formation

Removal of copper and cobalt from aqueous solutions using natural clinoptilolite

Spectroscopic Determination of Water Salinity in Brackish Surface Water in Nandoni Dam, at Vhembe District, Limpopo Province, South Africa

Occurrence and spatial distribution of statins, fibrates and their metabolites in aquatic environments

Sulfur/Gadolinium-Codoped TiO 2 nanoparticles for enhanced visible-light photocatalytic performance