Solubility of sodium oxalate in kraft black liquors below 100°C

Precipitation of sodium salts from kraft black liquor leads to scale formation in the evaporation plants of kraft pulp mills. Sodium oxalate scaling is most prevalent in mills pulping tropical hardwoods such as eucalyptus and acacia, but it has also been found in the scales in high solids lines after the concentrators in mills pulping softwoods. There is very limited solubility data for sodium oxalate in black liquor, especially below 100°C. This study measures the solubility limit in four different black liquors from 14% to 47% dry solids between 50 and 90°C. The newly generated solubility data in black liquors enhance our understanding of sodium oxalate scale formation in low solids effects of the evaporation plant. An example of an application to a kraft pulp mill with sodium oxalate scaling in the seventh effect is given.     

Single Molecule Localization Microscopy for Studying Small Extracellular Vesicles

Small extracellular vesicles (sEVs) are 30–200 nm nanovesicles enriched with unique cargoes of nucleic acids, lipids, and proteins. sEVs are released by all cell types and have emerged as a critical mediator of cell-to-cell communication. Although many studies have dealt with the role of sEVs in health and disease, the exact mechanism of sEVs biogenesis and uptake remain unexplored due to the lack of suitable imaging technologies. For sEVs functional studies, imaging has long relied on conventional fluorescence microscopy that has only 200–300 nm resolution, thereby generating blurred images. To break this resolution limit, recent developments in super-resolution microscopy techniques, specifically single-molecule localization microscopy (SMLM), expanded the understanding of subcellular details at the few nanometer level. SMLM success relies on the use of appropriate fluorophores with excellent blinking properties. In this review, the basic principle of SMLM is highlighted and the state of the art of SMLM use in sEV biology is summarized. Next, how SMLM techniques implemented for cell imaging can be translated to sEV imaging is discussed by applying different labeling strategies to study sEV biogenesis and their biomolecular interaction with the distant recipient cells.     

Recent Advancements in Design Optimization of Lattice-Structured Materials

Metamaterials, also known as lattice-structured materials, imitate the multifunctionality of natural architects as tailoring their physical properties is associated with manipulating their microstructure. As the recent evolution of additive manufacturing enables the creation of intricate geometries with minimal material wastage, improving the design to manufacturing cycle of lattice structured materials has become one of the trending research areas. Triply periodic minimal surface (TPMS) and plate lattice materials are renowned for their exceptional mechanical behavior in lightweight applications. Apparently, several types of design optimization strategies are explored to maximize their performance for better biocompatibility and mechanical loading resistance. Some of these strategies include functional gradation and multimorphology hybridization that are comprehensively described in this review. Their benefits and drawbacks are highlighted with a focus on TPMS and plate lattice materials. The review anticipates the utilization of automated design exploration methods (i.e., topology optimization and data-driven methods) to further enhance the design optimization procedure of lattice structured materials.     

Poly(vinylidene fluoride-co-hexafluoro propylene) membranes prepared via thermally induced phase separation and application in direct contact membrane distillation

A non-toxic and environmentally safe diluent, acetyl tributyl citrate, was employed to prepare poly(vinylidene fluoride)-co-hexafluoropropylene membranes via thermally induced phase separation. Effects of the polymer concentration on the phase diagram, membrane morphology, hydrophobicity, pore size, porosity and mechanical properties (tensile stress and elongation at break) were investigated. The results showed that the pore size and porosity tended to decrease with increasing polymer concentration, whereas the contact angle, liquid entry pressure and mechanical properties showed the opposite trend. In direct contact membrane distillation operation with 3.5 wt-% sodium chloride solution as the feed solution, the prepared membranes performed high salt rejection (>99.9%). Furthermore, the prepared membranes retained excellent performance in long-term stability tests regarding the permeate flux and salt rejection.     

Cavity inclination effect on convection flow in a triangular geometry

In this study, the water convection flow within a right-angled, inclined, and isosceles triangle enclosure for various inclination angles was numerically analyzed using the lattice Boltzmann method with the multirelaxation time model. On the hypotenuse side, the enclosure is thermally insulated, while the left and horizontal walls are kept, respectively, at cold and hot temperatures. This study was conducted to show the effects of two key parameters, the tilt angle $\varphi$ and the Rayleigh number $Ra$, whose changes span from $0^{\circ }$ to $315^{\circ }$ and $5\times 10^3$ to $10^6$, respectively. The effect of these variables is presented in terms of streamlines, isotherms, velocity profiles, temperature plots, and the average Nusselt number. Furthermore, the impact of the size of a hot square obstruction inside the cavity on the isotherms and streamlines has been investigated. The findings demonstrate that the rate of heat transport is enhanced as the Rayleigh number increases. This result is in good agreement with earlier research without tilting the cavity. Depending on the Rayleigh number, the tilt angle has a significant effect on the rate of heat transmission.     

A study on tool wear of tungsten carbide cutters in edge trimming of CFRP

Journal of Mechanical Science and Technology - Carbon fiber reinforced polymer (CFRP) composites are widely used in the aerospace field because of their outstanding lightweight material...     

Numerical modeling of conjugate heat transfer through concrete hollow bricks

The purpose of this study is to determine the thermal conductance of concrete hollow bricks, which is necessary for the evaluation of the energy efficiency of a building. The three varieties of hollow concrete bricks that are often used to build walls in Morocco are the subject of this study. A computational model created using the finite volume method is used to evaluate the conjugate heat transfer through concrete hollow bricks. According to the results, the use of hollow brick type A_h3 reduces the heat flux by approximately 86% compared with type A_h1. It is undeniable that hollow bricks type A_h3 with a thermal conductivity of 1 W/m K can improve the thermal characteristics of building walls.     

Real-time vibration monitoring and analysis of agricultural tractor drivers using an IoT-based system

Agricultural tractor drivers experience a high amplitude of vibration, especially during soil tillage operations. In the past, most research studied vibration exposure with more focus on the vertical (z) axis than on the fore-and-aft (x) and lateral (y) axes. This study examines how rotary soil tillage affects the vibration acceleration and frequency, and the power spectral densities (PSDs) at the seat pan and head along three translational axes in a real-field multiaxis vibration context. Moreover, this study aimed to identify the characteristics of the seat-to-head transmissibility (STHT) response to identifying the most salient resonant frequencies along the x-, y-, and z-axes. Nine (9) male tractor drivers operated the tractor with a mounted rotary tiller throughout the soil tillage process. In the event of a COVID-19 pandemic, and to respect social distancing, this study developed an Internet of Things (IoT) module with the potential to integrate with existing data loggers for online data transmission and to make the experimentation process more effective by removing potential sources of experimenter errors. The raw acceleration data retrieved at the seat pan and the head were utilized to obtain daily exposure (A(8)), PSDs, and STHT along the x-, y-, and z-axes. The vibration energy was found to be dominant along the z-axis than the x- and y-axes. A(8) response among tractor drivers exceeds the exposure action value explicitly stated by Directive 2002/44/EU. PSDs along the x-, y-, and z-axes depicted the low-frequency vibration induced by rotary soil tillage operation. The STHT response exhibited a higher degree of transmissibility along the y- and z-axes when compared with that along the x-axis. The frequency range of 4–7 Hz may plausibly be associated with cognitive impairment in tractor drivers during rotary soil tillage.     

Structural isomers in the perkin reaction. II. Products of interaction of 4-bromophthalic anhydride with phenylacetic acids and some of their reactions

Isomeric bromobenzalphthalides of type 1 were obtained by condensation of 4-bromophthalic anhydride with phenylacetic acids. Isomeric benzalphthalimidines of type 6–11 were also prepared and some of their reactions discussed.