Entry into force of the UN Watercourses Convention: why should it matter?

The United Nations Watercourses Convention entered into force on 17 August 2014, following a long and complex journey that dates back to 1970 when the UN referred the matter to its legal arm, the International Law Commission. This article follows the Convention through that long and turbulent road, examines its main provisions and analyses the reasons for the delay of its entry into force. It concludes by answering the question of why entry into force of the Convention should indeed matter.     

Deep-piRNA: Bi-Layered Prediction Model for PIWI-Interacting RNA Using Discriminative Features

Piwi-interacting Ribonucleic acids (piRNAs) molecule is a well-known subclass of small non-coding RNA molecules that are mainly responsible for maintaining genome integrity, regulating gene expression, and germline stem cell maintenance by suppressing transposon elements. The piRNAs molecule can be used for the diagnosis of multiple tumor types and drug development. Due to the vital roles of the piRNA in computational biology, the identification of piRNAs has become an important area of research in computational biology. This paper proposes a two-layer predictor to improve the prediction of piRNAs and their function using deep learning methods. The proposed model applies various feature extraction methods to consider both structure information and physicochemical properties of the biological sequences during the feature extraction process. The outcome of the proposed model is extensively evaluated using the k-fold cross-validation method. The evaluation result shows that the proposed predictor performed better than the existing models with accuracy improvement of 7.59% and 2.81% at layer I and layer II respectively. It is anticipated that the proposed model could be a beneficial tool for cancer diagnosis and precision medicine.     

Influence of fine ceramic aggregates on the residual properties of concrete subjected to elevated temperature

The residual properties of concrete subjected to elevated temperature are of importance to assess the stability of the structure. This paper investigates the performance of concrete containing white ware ceramic sand exposed to elevated temperature. Concrete mixes containing 0%, 50%, and 100% ceramic sand were prepared. The specimen were exposed to elevated temperatures of 200°C, 500°C, and 800°C for a duration of 60 minutes. Their residual mechanical properties (compressive strength, split tensile strength), ultra sonic pulse velocity, and mass change for different cooling regimes were investigated and compared among specimen. The results showed that incorporation of ceramic sand in concrete mixes improved the resistance against elevated temperature of hardened concrete.     

Pollen morphological investigations of family Cactaceae and its taxonomic implication by light microscopy and scanning electron microscopy

The family Cactaceae is the diversified group of angiosperm plants whose pollen statistics has been used for taxonomic identification. In this article, we present the pollen morphology of eight species belong to seven taxonomically complex genera of Cactaceae including Astrophytum, Cylindropuntia, Echinocereus, Echinopsis, Mammillaria, Opuntia, and Thelocactus using light and scanning electron microscopy. The pollen grains were acetolyzed, measured, described, and electron photomicrographs were taken. Cactaceae can be characterized by presenting different palynomorphological features including pollen type, sculpturing, polar and equatorial diameter, aperture orientation, exine thickness, P/E ratio, and echini features. Four types of pollen shapes, that is, prolate spheroidal (three species), subprolate (two species), prolate (two species), and oblate spheroidal in Echinocereus reichenbachii were observed. The polar and equatorial diameter observed maximum in O. ficus indica 116.95 and 112.27 μm while minimum in M. compressa 38.42 and 21.05 μm. Pollen of two types, tricolpate in members of subfamily Cactioideae and pantoporate in the Opuntioideae were examined. The fertility percentage has been observed maximum in Opuntia macrocentra (83.84%) and minimum in Opuntia ficus‐indica (57.89%). Exine sculpturing showing great variations such as granulate, reticulate, granulate perforate and micro‐echinate foveolate ornamentation was examined only in Echinopsis eyriesii. A key to species, based on pollen micromorphological attributes, has been constructed for correct identification of complex cactus species.     

Geothermal and solar energy–based multigeneration system for a district

In this study, parabolic trough collector with an integrated source of geothermal water is used with regenerative Rankine cycle with an open feedwater heater, an electrolyzer, and an absorption cooling system. The absorption fluids used in the solar collectors were Al₂O₃‐ and Fe₂O₃‐based nanofluids. Detailed energetic and exergetic analyses are done for the whole system including all the components. A comparative analysis of both the used working fluids is done and plotted against their different results. The parameters that are varied to change the output of the system are ambient temperature, solar irradiance, the percentage of nanofluids, the mass flow rate of the geothermal well, the temperature gradient of the geothermal well that had an effect on the net power produced, and the outlet temperature of the solar collector overall energetic and exergetic efficiencies. Other useful outputs by this domestic integrated multigeneration system are the heating of domestic water, space heating (maintaining the temperature at 40°C‐50°C), and desalination of seawater (flash distillation). The hydrogen production rate for both the fluids diverges with each other, both producing average from 0.00490 to 0.0567 g/s.     

Synthesis of Au/UiO-66-NH2/Graphene composites as efficient visible-light photocatalysts to convert CO2

The production of new solar fuel through CO₂ photocatalytic reduction has aroused tremendous attention in recent years because of the increased demand of global energy sources and global warming caused by the mass concentration of CO₂ in the earth's atmosphere. In this work, UiO-66-NH₂ was co-modified by the Au nanoparticles (Au-NPs) and Graphene (GR). The resultant nanocomposite exhibits a strong absorption edge in visible light owing to the surface plasmon resonance (SPR) of Au-NPs. More attractively, Au/UiO-66-NH₂/GR displays much higher photocatalytic activity (49.9 μmol) and selectivity (80.9%) than that of UiO-66-NH₂/GR (selectivity: 71.6%) and pure UiO-66-NH₂ (selectivity: 38.3%) for the CO₂ reduction under visible light. The enhanced photocatalytic performance is primarily dued to the surface plasmon resonance (SPR) of Au-NPs, which could enhance the visible light absorption. The GR sheets could play as an electron acceptor with superior conductivity and thus suppress the recombination of electrons and holes. Besides, the GR could also improve the dispersibility of UiO-66-NH₂ so as to expose more active sites and strengthen the capture of CO₂. The contact effect and synergy effect among different samples are strengthened in the ternary composites and the photocatalytic performance is therefore improved. This study demonstrates a MOF based hybrid composite for efficient photocatalytic CO₂ reduction, the findings not only prove great potential for the design and application of MOFs-based materials but also bring light to novel chances in the development of new high performance photocatalysts.     

Deterioration and Recovery of Metakaolin Blended Concrete Subjected to High Temperature

The deterioration and spalling frequency of metakaolin (MK) blended concrete subjected to high temperature is analyzed and compared with the equivalent silica fume (SF), fly ash (FA) and pure OPC concretes. Normal and high strength concrete mixes incorporating 0–20% MK were prepared and exposed to a series of high temperatures till 800°C. The residual compressive strength, porosity and pore size distribution were determined. It was found that after an increase in compressive strength at 200°C, the MK concrete suffered a more severe loss of compressive strength and permeability-related durability than the corresponding SF, FA, and pure OPC concretes at higher temperatures. Explosive spalling was observed in both normal and high strength MK concretes, and the frequency increased with higher MK contents. It is concluded that the dense micro-structure and low porosity are the main reasons of the poor performance of MK concrete at high temperature. The effect of post-fire curing on the strength and durability recovery of fire-damaged concrete was also investigated. The test results indicated that the post-fire curing, results in substantial strength and durability recovery, and its extent depends upon the types of concrete, exposure temperature, method, and duration of re-curing.     

Synergistic effect of salt ions and water-soluble amphiphilic compounds of acidic crude oil on surface and interfacial tension

This study investigated the effect of solubility of amphiphilic compounds of acidic crude oil in water on the surface and interfacial tension (IFT) with NaCl, MgCl₂, CaCl₂, and Na₂SO₄ salts. Accordingly, distilled water, along with the salts mentioned in zero ionic strength up to 2 mol were put in contact with crude oil to become saturated with amphiphilic compounds. The effects of these compounds were investigated on the properties of contact water by pH, total organic carbon (TOC), FTIR (Fourier transform infrared spectroscopy), water-air surface tension (ST), and water-n-decane IFT tests. The results showed that some of the organic components of crude oil, especially acidic and basic compounds, are present or soluble in water, which have a significant effect on reducing the surface and IFT. The IFT reduction of water-n-decane was greater than the water-air ST system. Also, the observations showed that for both NaCl and Na₂SO₄ salt water, with increasing ionic strength of water, there was an optimum salinity within the range of 0.1-0.25 mol/L for both salts with the amount of surface and IFT minimized at this point. In the other two salts, this point was delayed upon elevation of ionic strength and was observed at high salinity. In this case, divalent cations reduce tension rate compared to monovalent cations. Due to solubility of acidic and basic groups in water, pH of salt water illustrates an acidic trend. Results of the FTIR test confirmed solubility of these compounds as well.     

Mechanical Properties and Microstructure of a Metakaolin-Based Inorganic Polymer Mortar Reinforced with Quartz Sand

Silicon - The synthesis, mechanical behaviour, and microstructure of metakaolin-based geopolymer mortar reinforced with quartz sand are presented in this investigation. Fine sand (quartz sand)...