Completely FROST-ed: IoT issued FROST signature for Hyperledger Fabric blockchain

Threshold signatures play a crucial role in the security of blockchain applications. An efficient threshold signature can be applied to enhance the security of wallets and transactions by enforcing multi-device-based authentication, as this requires adversaries to compromise more devices to recover the key. Additionally, threshold signatures can...

Plant–atmosphere heat exchange during wind machine operation for frost protection

To mitigate spring frost damage, fruit farmers use wind machines to mix warm overlying air down to the vegetation. Up to this point, studies on wind machine efficiency have focused on air temperatures. The temperature of different plant organs during operation remains unknown, while critical for the actual degree of frost damage. With...

Behavior of Engineered Cementitious Composites (ECCs) Subjected to Coupled Sustained Flexural Load and Salt Frost

The performance of engineered cementitious composites (ECCs) under coupled salt freezing and loaded conditions is important for its application on the transportation infrastructure. However, in most of the studies, the specimens were generally loaded prior to the freezing. The influence of sustained load was merely considered. To this end,...

Wind machines for frost damage mitigation: A quantitative 3D investigation based on observations

Wind machines have been increasingly used for frost damage mitigation in the agricultural community. During radiative frost nights, wind machines are used to erode near-surface thermal inversion by air mixing. The underlying mixing processes remain poorly understood. A full picture of warming effects caused by air mixing requires measurements...

Surface Tensile Strength and Hertzian Fracture Resistance of Patterned Acid-Etched Glass

Patterned acid-etched glasses are frequently used in horizontal glass surfaces that may be walked on, such as floors and staircase treads. These glasses provide useful antislip properties, but the foot traffic cause contact stresses and ageing mechanisms that are poorly understood and can affect the strength of the acid-etched glass. This...

X-ray micro-tomographic imaging and modelling of saline ice properties in concrete frost salt scaling experiments

Frost salt scaling of concrete is related to cyclic freezing and melting of a few millimeter thick deicer solution on the surface of the concrete. It is almost absent when pure water is freezing and reaches a maximum at a so-called pessimum concentration that for NaCl is around 3%. Different mechanisms have been suggested to explain this...

Effect of superabsorbent polymer introduction on properties of alkali-activated slag mortar

Internal curing by superabsorbent polymer (SAP) has been applied in alkali-activated slag (AAS) systems by a few previous studies with the purpose to mitigate the autogenous shrinkage. However, the effects of SAP on other properties of AAS have been rarely studied. In this paper, the workability, strength, permeability, and frost resistance...

Revisiting concrete frost salt scaling: On the role of the frozen salt solution micro-structure

We simulate the glue-spall stress due to mechanical interactions between a frozen saline solution (brine-ice composite) and a non-air entrained concrete surface including the impact of the micro-structure of the frozen solution. The presence of brine channels at the ice/concrete interface was found to be a prerequisite to induce stress during...

Modeling heat transfer in the vegetation-soil continuum

This thesis contributes to the scientific underpinning of the battle against fruit frost. Fruit frost is the freezing damage to blossoms when in the growing season the night temperature drops below 0±C. This results in damaged or undeveloped fruits, and a yield loss for the fruit farmer. Several techniques against fruit frost have been developed...

Exploring the potential of nano-SiO2 to prevent early-age frost damage in Portland cement paste

The purpose of this study is to explore the potential of nano-SiO2 (NS) to prevent early frost damage, and the effect of nano-SiO2 (NS) on cement pastes subjected to early-age freezing was investigated regarding the macro properties (strength and durability) and micro properties (hydration and microstructure). The specimens were prepared with NS...

Towards a physics-based understanding of fruit frost protection using wind machines

Wind machines are used to prevent or mitigate the adverse effects of night frost in spring. These frost events occur during clear-sky, low-wind nights in which a thermal inversion builds up from the surface. The machines work by mixing and transporting warm air from aloft downward which consequently erodes the thermal inversion. Various studies...

Frost Damage Progression Studied Through X-Ray tomography In Mortar With Phase Change Materials

The potential of using phase change materials (PCM) in cementitious materials to mitigate damage due to thermal loadings has been recently focus of intensive research. In the case of PCM with transition temperatures near to the freezing point of water, their potential to delay frost in a cementitious matrix has been largely investigated through...

Cryogenic suction pump mechanism for combined salt-and frost exposure

Freezing of water can be explained by the thermodynamic properties of the water due to the influence of temperature, pressure and special effects such as surface tension and salt solution. Gibbs free energy curves for ice and pore liquid containing different concentrations of NaCl (0-6%) are presented. These curves explain the onset of freezing...

The characterisation, improvement and modelling aspects of Frost Salt Scaling of Cement-Based Materials with a High Slag Content

Blast furnace slag cement concrete is used extensively in a number of countries. In comparison with OPC, it is particularly well known for its excellent performance in marine environments. One dis-advantage of slag cement is its vulnerability to scaling under the combined load of freezing-thawing and de-icing salts. The current investigation was...

Influence of frost formation and defrosting on the performance of air coolers: Standards and dimensionless coefficients for the system designer