A New Method for the Analysis of Soluble and Insoluble Oxalate in Pulp and Paper Matrices

A novel method has been developed for determining soluble and insoluble forms of oxalate in pulp and paper samples by ion chromatography. Methanesulphonic acid is used to dissolve insoluble oxalate, and total oxalate is then determined by ion chromatography with suppressed conductivity detection. Soluble oxalate is determined directly by ion chromatography, without prior chemical treatment. Insoluble oxalate is obtained by difference. The method was applied to samples of pulp, process liquors, filtrates, and scale deposits from kraft mills. In kraft mills, considerably higher levels of oxalate were found in the Eop samples compared to those in the brownstock and D₀ samples. In both brownstock and Eop samples, oxalate was mainly present in soluble form, whereas the D₀-stage contained relatively higher levels of insoluble oxalate.     

Potassium supplying capacity of some tropical alfisols in southwest Nigeria as measured by intensity,quantity and capacity factors

Experiments were conducted in the laboratory, greenhouse and on farmers’ fields to determine, the potassium (K) supplying capacity of some soils in Ogun State, Nigeria, using equilibrium parameters as measured by quantity, intensity and activity indices. The result showed that the potassium status of the soils varied widely. Total K varied from 14.2 to 104 cmol kg⁻¹ in the green house soils and 46.05 to 89.1 cmol kg⁻¹ in the field soils. On the average, exchangeable and solution K constituted 0.39 and 0.09% of the total K, respectively in the greenhouse soils. The potential buffer capacity (PBC), which measures the ability of the soil to maintain the intensity of K in the soil solution, varied from 12.24 to 39.25 (ML^−1/2). About 50% of the soils studied in the green house and in the field have high PBC indicating slow release of K to the soil solution. The specifically bonded K which constituted the bulk of the labile K (K_L) that is immediately available is generally low. It ranged from 0.10 to 0.29 cmol kg⁻¹ with a mean of 0.18 cmol kg⁻¹ in the greenhouse soils, and mean of 0.16 cmol kg⁻¹ in the field soils. These low values accounted for the appreciable responses to K application by soybean in most of the soils studied. The change in Gibb’s free energy (ΔG) values, which measures the intensity of exchangeable K relative to other cations, is moderate in most of the soils. Correlation analysis showed that all the forms of K correlated positively and significantly with soybean dry matter yield at the first cropping harvest. However, soybean K concentration in the first harvest was only positively correlated with available K, exchangeable K, solution K and fixed K (P < 0.01). The clay content of the soil is also positively and significantly correlated with K forms. The prediction equation showed that the soil’s clay content is a major determinant of labile K, equilibrium activity ration (EAR) and the potential buffering capacity. The EAR is also strongly determined by the ECEC and the K saturation (R ² = 0.990, 0.996, P < 0.01). The critical level of soil labile K, available K and specifically bonded K are 0.21, 0.35, and 0.19 cmol kg⁻¹, respectively. Thus, with the use of available K as the index of K fertility, about 50% of the soils are K deficient. Hence potassium fertilization is necessary for enhanced production of soybean in these sites.     

Conductivity of libob-based electrolyte for lithium-ion batteries

This work reports the use of mixtures of γ-butyrolactone (GBL) and ethyl acetate (EA), with and without ethylene carbonate (EC), as solvents for lithium bis(oxalato)borate (LiBOB) salt as potential electrolytes for Li-ion cells. The effects of salt concentration, ethylene carbonate (EC) content, and temperature on the conductivity and viscosity of the mixture are reported. Results indicate that the best electrolyte for high-temperature application is that which contains 1 kmol m⁻³ LiBOB in GBL + EA + EC of composition 1:1:0.1 (wt). For low-temperature applications, the best electrolyte is that which contains 0.7 kmol m⁻³ LiBOB in GBL + EA + EC of composition 1:1:0 (wt). The product of conductivity with viscosity was essentially independent of temperature but was dependent on solvent composition showing that at fixed salt concentration, the viscosity is the major criteria affecting electrolyte conductivity rather than dielectric constant.     

Microstructure,Hardness, and Wear Assessment of Spark-Plasma-Sintered Ti-xAl-1Mo Alloy

Metallurgical and Materials Transactions A - Alloys from the Ti-Al-Mo ternary system are of high importance in aerospace applications due to their excellent specific strength-to-density ratio,...     

In vitro monocyte adhesion and activation on modified FEP copolymer surfaces

The functional group content and the ionic state of functional groups present on a series of surface modified poly(tetrafluoroethylene/hexafluoropropylene) (FEP) copolymers were characterized by electron spectroscopy for chemical analysis (ESCA), contact angle, and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Additionally, after a protein was preadsorbed on these surfaces, in vitro cell (monocyte) adhesion and activation were analyzed. The two proteins in this study were fibrinogen and immunoglobulin-G (IgG). Four modified FEP surfaces were prepared with increasing concentration of carboxyl groups relative to amide groups; ESCA was used to quantify the functional group content. To characterize the ionic state of the functional groups at physiological pH (7.1), the ATR-FTIR spectra were collected at various pH levels. Collectively, the contact angle, ESCA, and ATR-FTIR results suggested that the amide groups were unprotonated and the carboxyl groups were ionized at the physiological pH. The results from the in vitro studies showed that on the fibrinogen preadsorbed surfaces, monocyte adhesion was higher and monocyte activation was lower on the three surfaces that contained carboxyl groups compared to the FEP surface that had only amide groups. Conversely, the results indicated that the surface chemistry had no significant effect on monocyte adhesion or activation on the IgG preadsorbed surfaces. © 1995 John Wiley & Sons, Inc.     

A study to determine electromagnetic interference-shielding effectiveness on bio-based polyurethane foam reinforced with PVDF/MgO/Ni for emerging applications

The main objective of this study is to prepare nanoparticles-induced bio-based polyurethane foam to shield electromagnetic interference (EMI) radiation in the 8–12 GHz frequency range and compare the experimental result with optimization and simulation. Polyvinylidene fluoride (PVDF), magnesium oxide (MgO), and Nickel (Ni) nanoparticles were induced into bio-based PU (polyurethane) foam through absorption and hydrothermal reduction technique, which includes mechanical stirring, compressing, heating and evaporating. The design of experiment (DOE) methodology was used to find nanoparticle weight percentage (wt%). EMI shielding effectiveness of the bio-based PU foam composite was measured using Vector Network Analyzer (N5230A PNA-L). The weight percentages of the optimized sample were predicted using the response surface methodology (RSM), in which the central composite design (CCD) employed the weight percentages of the three nanoparticles as input and the results of the electromagnetic interference shielding effectiveness (EMI SE) experiment as the response output. The result from CCD showed that 3 wt% of PVDF, 10 wt% of MgO, and 1 wt% of Ni gave a maximum EMI SE of 27.78 dB. Then a confirmation sample was created for the same, and EMI SE was estimated empirically. The results obtained for the confirmation sample are 27.56 dB. Then, a scanning electron microscope image was taken for the confirmation sample to analyze nanoparticle-induced bio-based PU foam's structural properties. The SEM image with dxf format is imported into the radio frequency (RF) module to calculate the EMI SE through COMSOL Multiphysics. The simulated EMI SE for the confirmation sample was 25.1 dB.     

Redox Responsive Copolyoxalate Smart Polymers for Inflammation and Other Aging-Associated Diseases

Polyoxalate (POx) and copolyoxalate (CPOx) smart polymers are topics of interest the field of inflammation. This is due to their drug delivery ability and their potential to target reactive oxygen species (ROS) and to accommodate small molecules such as curcumin, vanilline, and p-Hydroxybenzyl alcohol. Their biocompatibility, ultra-size tunable characteristics and bioimaging features are remarkable. In this review we discuss the genesis and concept of oxylate smart polymer-based particles and a few innovative systemic delivery methods that is designed to counteract the inflammation and other aging-associated diseases (AADs). First, we introduce the ROS and its role in human physiology. Second, we discuss the polymers and methods of incorporating small molecule in oxalate backbone and its drug delivery application. Finally, we revealed some novel proof of concepts which were proven effective in disease models and discussed the challenges of oxylate polymers.     

Utilizing demand-side management as tool for promoting solar water heaters in countries where electricity is highly subsidized

In many countries, especially those that produce petrol, electricity consumption is often subsidized. This policy leads to very low electricity costs and precludes the widespread use of solar water heaters, which have proven to be economically viable and are extensively utilized in other countries. Herein, we propose a new demand-side planning methodology to deal with such cases and perform an experimental finding–based economic assessment to study the feasibility of reducing subsidies in return for providing brand new solar water heaters to consumers. Specifically, solar water heaters are proposed to be supplied and installed free of charge as part of a demand-side management program in the Erbil province (Kurdistan region, Iraq). Assuming a duration of ten years, we show that the proposed project has a net present value of approximately US$776.6 million and requires an investment of US$90 million, further demonstrating that the successful launch of this project should dramatically reduce the winter peak load of 54 MW.     

Current and future trends of additive manufacturing for chemistry applications: a review

Three-dimensional (3-D) printing, also known as additive manufacturing, refers to a method used to generate a physical object by joining materials in a layer-by-layer process from a three-dimensional virtual model. 3-D printing technology has been traditionally employed in rapid prototyping, engineering, and industrial design. More recently, new applications continue to emerge; this is because of its exceptional advantage and flexibility over the traditional manufacturing process. Unlike other conventional manufacturing methods, which are fundamentally subtractive, 3-D printing is additive and, therefore, produces less waste. This review comprehensively summarises the application of additive manufacturing technologies in chemistry, chemical synthesis, and catalysis with particular attention to the production of general laboratory hardware, analytical facilities, reaction devices, and catalytically active substances. It also focuses on new and upcoming applications such as digital chemical synthesis, automation, and robotics in a synthetic environment. While discussing the contribution of this research area in the last decade, the current, future, and economic opportunities of additive manufacturing in chemical research and material development were fully covered.

Graphical abstract

     

Cissus Populnea Fiber - Unsaturated Polyester Composites: Mechanical Properties and Interfacial Adhesion

ABSTRACT

Mechanical (flexural, hardness, and impact) properties and interfacial adhesion of acetic anhydride (AC) and ethylene diamine tetraacetic acid (EDTA) treated Cissus populnea fiber-unsaturated polyester (UPR) composites was investigated because of poor durability of the natural fiber-UPR composite applications. UPR composites were prepared with untreated and optimally treated fiber using hand-lay-up technique. Optimization of mechanical properties and interfacial adhesion between the fiber and UPR were determined using response surface methodology and fiber pull-out method, respectively. AC and EDTA treated fibers improved the flexural and hardness properties and interfacial adhesion at reduced impact strength. This is corroborated with morphology of the composites.