Reactivity of industrial wastes as measured through ICP-OES: A case study on siliceous Indian biomass ash

An untapped source of amorphous SiO₂, industrially generated Indian biomass ash (SA)—90% amorphous, with composition of ~60% SiO₂ and ~20% unburnt carbon—can be used to produce cementitious and alkali-activated binders. This study reports dissolution of amorphous Si from SA in 0.5 mol/L and 1 mol/L aqueous NaOH, with and without added Ca(OH)₂, at SA:Ca(OH)₂ wt% ratios of 100:0, 87.5:12.5, and 82.5:17.5. Monitoring of elemental dissolution and subsequent/simultaneous product uptake by ICP-OES offers an effective process for evaluating utility of industrial wastes in binder-based systems. After 28 days in solution, up to 68% of total Si is dissolved from SA in 1 mol/L NaOH, with values as much as 38% lower in the presence of Ca(OH)₂, due to the formation of tobermorite-like C-S-H. FTIR, ²⁹Si MAS-NMR, and XRD are used to characterize solid reaction products and observe reaction progress. Product chemistries calculated from ICP-OES results and verified by selective dissolution in EDTA/NaOH—namely, Ca/Si of 0.6-1 and Na adsorption of 1-2 mmol/g—are found to be consistent with those indicated by aforementioned techniques. This indicates the efficacy of ICP-OES in estimating product chemistry via such a methodology.     

Efficient prediction of drug–drug interaction using deep learning models

A drug–drug interaction or drug synergy is extensively utilised for cancer treatment. However, prediction of drug–drug interaction is defined as an ill‐posed problem, because manual testing is only implementable on small group of drugs. Predicting the drug–drug interaction score has been a popular research topic recently. Recently many machine learning models have proposed in the literature to predict the drug–drug interaction score efficiently. However, these models suffer from the over‐fitting issue. Therefore, these models are not so‐effective for predicting the drug–drug interaction score. In this work, an integrated convolutional mixture density recurrent neural network is proposed and implemented. The proposed model integrates convolutional neural networks, recurrent neural networks and mixture density networks. Extensive comparative analysis reveals that the proposed model significantly outperforms the competitive models.Inspec keywords: cancer, learning (artificial intelligence), drugs, recurrent neural nets, convolutional neural nets, drug delivery systemsOther keywords: drug synergy, drug–drug interaction score, drug–drug interaction prediction, deep learning, cancer treatment, machine learning, convolutional mixture density recurrent neural network     

Effect of hook characteristics on the fracture behaviour of dissimilar friction stir welded aluminium alloy and mild steel sheets

ABSTRACT

Under tensile shear loading, fracture modes of dissimilar lap welds produced by friction stir scribe technology were studied. Three fracture modes were observed. For zone A fracture, the initial crack was restrained, and the joint ultimately fractured in the base mild steel. For zone B fracture, the initial crack progressed through the aluminium sheet just above the Al/steel interface. For zone C fracture, the initial crack proceeded along the steel hook to the aluminium sheet surface. Fracture mode and joint strength were greatly influenced by steel hook size, and the steel hook size was affected by welding parameters and tool scribe height. In this study, the experimental joint strength achieved the calculated joint load limit.     

The limits of the analogy between boiling and gas evolution at electrodes

The processes of gas evolution at electrodes in electrochemical reactors and of boiling belong to strongly different fields in chemical engineering and for a long time were investigated separately. Nonetheless, they exhibit numerous common features. The analogies of both processes have been made use of giving rise to transfer findings obtained in one field to the other one. However, the analogy is limited, and the limitations have not yet attracted sufficient interest. A brief review on the analogies is given. The discrepancies in the fields of initial nucleation, the upper bound of operation and the different mechanisms controlling the transport of substance and of heat in both processes are discussed.     

Synthesis and characterization of waterborne and phosphorus-containing flame retardant polyurethane coatings

Phosphorus-containing flame retardant water-dispersed polyurethane coatings were produced by incorporating different amounts of a phosphorus compound onto the polyurethane main chain. The novel phosphorus containing compound (phosphorus phenyl dihydroxy) was synthesized in three steps using benzaldehyde, pentaerythritol, phenyl phosphonic dichloride, and acetic acid. The addition of phosphorus phenyl dihydroxy to the main chain of polyurethane, in which NCO/OH ratio was kept constant at 1.5 and the amount of dimethylolpropionic acid (DMPA) at 3.5 wt%, increased the hardness and abrasion resistance, but only slightly decreased the gloss values of the polyurethane paints. All the samples showed superior impact resistance and flexibility. Moreover, increasing the phosphorus content increased the char yield, and the maximum fire retardancy was reached at 1.5% P content with a limiting oxygen index (LOI) value of 29. Kimya B?lümü, 06531 Ankara, Turkey.     

The change of phase composition in kaolinite- and illite-rich clay-based ceramic bodies

Raw material for ceramics consists mainly of kaolinite, illite, quartz and feldspar. Three representative clays, a high kaolinitic (HB), illitic- and quartz-rich (KW) and naturally mixed kaolinite–illite (P1) clays of Westerwald area, were chosen for this study [Kromer, H., 1980. Tertiary clays in the Westerwald area. Geol. Jb. D. Rhei D Hanover, 69–84]. The largest and oldest clay mining area of Germany is in the Westerwald area. These clays were mixed with each other and also with K, and Ca–Na feldspar. The high temperature phases of the mixed bodies were of three groups: crystalline phase, amorphous/glassy phase and porosity.The aim of this study was to determine: (1) the effect of kaolinite–illite–quartz ratios, (2) the effect of heat treatment and (3) the effect of feldspar on the fired mineralogy of the fired products. The crystalline phases are cristobalite, mullite, quartz, hematite and anatase. The bodies consist of crystalline phases such as quartz, mullite and cristobalite in a composite structure where crystals and pores are often embedded in amorphous/glassy phase. The formation of mullite and cristobalite is very distinctive in kaolinitic clay, and the structure is dominated by the spiky primary mullite. In the illite/sericite-rich mixtures, the high K content causes a large amount of melt superimposed on the mullite formation. The cristobalite formation is completely suppressed in illite/sericite-rich bodies. After dehydroxylation, metakaolinite and illite/sericite anhydride structures are formed. The persistence of illite/sericite anhydride peaks above 950 °C in KW clay indicates the presence of sericite/muscovite mineral. The disappearance temperatures and firing behaviour of K and Ca–Na feldspar observed within the XRD patterns of mixed bodies are different. K feldspar lines disappear earlier in HB bodies than in KW bodies, but Ca–Na feldspar shows a reverse behaviour. While Ca–Na feldspar peak intensity gradually decreases but persists at 1150–1250 °C, K feldspar suddenly disappears at 1150 °C.     

Radiochemical neutron activation analysis of zinc isotopes in human blood, urine, and feces for in vivo tracer experiments

Enriched stable isotopes are being increasingly used for study of trace element nutrition in humans who cannot be studied by use of in vivo radioactive tracers (e.g., subjects under age 18 and pregnant women). Zinc metabolism in these subjects can be evaluated by administration of Zn enriched to 65% in the minor isotope, 70Zn (0.6% natural abundance). The enhanced 70Zn is detected later in red blood cells, plasma, urine, and feces by measuring 70Zn/64Zn or 70Zn/68Zn ratios. Stable isotope concentrations are measured by neutron activation of the samples and observation of their products: 244-day 65Zn, 14-h 69mZn, and 4-h 71mZn. Zinc-65 can be observed in these samples without chemical separations 3 weeks after irradiations, but large amounts of 24Na and other short-lived species preclude direct observation of the short-lived Zn activities. Preirradiation chemistry was developed to remove most interferences, the major steps being to place the sample on Chelex resin, elute alkali metals and alkaline earths from it, and irradiate the resin containing the Zn. gamma-Rays of 69mZn can be observed on the irradiated resin, but additional precipitation and solvent extraction steps are needed to remove 56Mn and 64Cu for clear observation of 71mZn and 65Zn within hours after irradiation. Yields for pre- and postirradiation separations are typically 85% and 70%, respectively. The stable isotope tracer method was validated by simultaneous in vivo tracing with radioactive 65Zn in four subjects.     

Economic comparison of current electricity generating technologies and advanced nuclear options

This analysis compares the cost of various electric grid scenarios at the national level over a one-year period. Scenarios include high renewable, zero nuclear, zero carbon, and deployment of advanced nuclear. Additionally, several carbon tax scenarios are explored in the model to further assess the cost generation if the current nuclear fleet retired. The cheapest scenarios were those that involved less reliance on conventional nuclear reactors and more molten salt reactors, renewables, or natural gas.     

Wind energy status and its assessment in Turkey

The increase in negative effects of fossil fuels on the environment has forced many countries, especially the developed ones, to use renewable energy sources. Currently the fastest developing energy source technology is wind energy. Because wind energy is renewable and environment friendly, systems that convert wind energy to electricity have developed rapidly. Wind energy is an alternative clear energy source compared to the fossil fuels that pollute the lower layer of atmosphere. Because wind energy will be used more and more in the future, its current potential, usage, and assessment in Turkey is the focus of this study.