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Examination of the underlying chemical physics of the Mpemba effect in water and other liquids

Khan et al. | Apr 20, 2023

Examination of the underlying chemical physics of the Mpemba effect in water and other liquids
Image credit: D koi

Counterintuitive in nature, the Mpemba effect asserts that hot liquid freezes faster than cold liquid. While noted throughout history by scientific minds like Aristotle, the phenomenon remains in contention with varying hypotheses for the effect proposed alongside the effect’s rise in popularity. Contributing to the research efforts surrounding the Mpemba effect, the authors in this article explore the effect in different liquids ranging in physical properties and intermolecular forces to determine potential parameters attributable to producing the Mpemba effect.

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The Effect of Bead Shape and Texture on the Energy Loss Characteristics in a Rotating Capsule

Misra et al. | Jan 25, 2019

The Effect of Bead Shape and Texture on the Energy Loss Characteristics in a Rotating Capsule

Industrial process are designed to optimize speed, energy use and quality. Some steps involve the translation of product-filled barrels, how far and fast this happens depends on the properties of the product within. This article investigates such properties on a mini-scale, where the roll of bead size, texture and material on the distance travelled by a cylindrical capsule is investigated.

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Redesigning an Experiment to Determine the Coefficient of Friction

Hu et al. | Jun 27, 2016

Redesigning an Experiment to Determine the Coefficient of Friction

In a common high school experiment to measure friction coefficients, a weighted mass attached to a spring scale is dragged across a surface at a constant velocity. While the constant velocity is necessary for an accurate measurement, it can be difficult to maintain and this can lead to large errors. Here, the authors designed a new experiment to measure friction coefficients in the classroom using only static force and show that their method has a lower standard deviation than the traditional experiment.

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The Effect of Cobalt Biomineralization on Power Density in a Microbial Fuel Cell

Bandyopadhyay et al. | Sep 07, 2015

The Effect of Cobalt Biomineralization on Power Density in a Microbial Fuel Cell

A microbial fuel cell is a system to produce electric current using biochemical products from bacteria. In this project authors operated a microbial fuel cell in which glucose was oxidized by Shewanella oneidensis in the anodic compartment. We compared the power output from biomineralized manganese or cobalt oxides, reduced by Leptothrix cholodnii in the cathodic compartment.

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Assessing CDK5 as a Nanomotor for Chemotactic Drug Delivery

Jiang et al. | Sep 08, 2022

Assessing CDK5 as a Nanomotor for Chemotactic Drug Delivery

Enzyme chemotaxis is a thermodynamic phenomenon in which enzymes move along a substrate concentration gradient towards regions with higher substrate concentrations and can be used to steer nanovehicles towards targets along natural substrate concentrations. In patients with Alzheimer’s disease, a gradient of tau protein forms in the bloodstream. Tau protein is a substrate of the enzyme CDK5, which catalyzes the phosphorylation of tau protein and can travel using chemotaxis along tau protein gradients to increasing concentrations of tau and amyloid-beta proteins. The authors hypothesized that CDK5 would be able to overcome these barriers of Brownian motion and developed a quantitative model using Michaelis-Menten kinetics to define the necessary parameters to confirm and characterize CDK5’s chemotactic behavior to establish its utility in drug delivery and other applications.

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The Impact of Effective Density and Compressive Strength on the Structure of Crumpled Paper Balls

Chu et al. | Nov 19, 2020

The Impact of Effective Density and Compressive Strength on the Structure of Crumpled Paper Balls

Crumpling is the process whereby a sheet of paper undergoes deformation to yield a three-dimensional structure comprising a random network of ridges and facets with variable density. The authors hypothesized that the more times a paper sheet is crumpled, the greater its compressive strength. Their results show a relatively strong linear relationship between the number of times a paper sheet is crumpled and its compressive strength.

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Effects of Temperature on Hand Sanitizer Efficiency

Molom-Ochir et al. | May 11, 2022

Effects of Temperature on Hand Sanitizer Efficiency

Here, recognizing the widespread use of hand sanitizers, the authors investigated their effectiveness in relation to storage temperature. They applied hand sanitizer before and after touching a cell phone and used LB-agar plates to monitor the growth of bacteria following this process. They found that 70% ethyl-alcohol-based sanitizers are least effective at temperatures above 107.27 °F and most effective at 96.17 °F.

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