Performance of Cleanroom Garment Fabrics When Processed in an Industrial Laundry, Comparing Irradiation and Autoclave Sterilisation

EU GMP Annex 1 requires that “reusable garments should be replaced based at a set frequency determined by qualification, or if damage is identified.” [1] In the UK, most cleanroom garments supplied to the pharmaceutical and healthcare sectors are washed and sterilised by gamma irradiation. This study compares cleanroom garment fabric performance across the lifespan of multiple fabrics. Previous research has shown that cleanroom garment fabrics terminally sterilised by gamma irradiation remain suitable for use for up to 50 processes, however, these studies often focus on a limited number of samples. This study uses a large sample set, analysing the performance up to 100 processes and compares the performance effects of gamma irradiation vs autoclaving, as an alternative sterilisation method. Multiple market leading cleanroom garment fabrics were washed and dried using a standard industrial cleanroom laundry process and sterilised by either gamma irradiation or autoclave. They were tested for particle barrier efficiency, abrasion resistance, pore size, and tensile strength as new, then at set process counts throughout their life, 10, 20, 30, 50, 70 and 100 processes. A process is equal to one wash/dry/sterilisation cycle. The results show that not all cleanroom garment fabrics deteriorate equally and that some market leading fabrics may not provide adequate performance throughout life, even if they are suitable when new. They also show that autoclaving is comparable with irradiation in durability and performance over a fabric’s life, in some cases performing better than irradiation above process counts of 50.

Full scale experiments to examine the role of deadwood on rockfall dynamics in forests

Forests are rockfall-protective ecological infrastructures, as a significant amount of kinetic energy is absorbed during consecutive rock-tree impacts. Although many recent works have considered rock impacts with standing trees, the effect of lying deadwood in forests has not yet been considered thoroughly, either experimentally or numerically. Here, we present a complete examination of induced rockfall experiments on a forested area in three different management stages. The trilogy is conducted in a spruce forest stand (i) in its original state, (ii) after a logging operation with fresh, lying deadwood and (iii) after the removal of the deadwood. The tests allow us to directly quantify the effect of fresh deadwood on overall rockfall risk for the same forest (slope, species) under three different conditions. The study yields quantitative results on the barrier efficiency of the deadwood logs as only 3.6 % of the rocks surpass the deadwood section. The mean runout distance is reduced by 42 %. Conversely, the runout distance increases by 17 % when the cleared stand is compared to the original forest. These results quantitatively confirm the benefits of nature-based mitigation measures integrated into forestry practice and we show how modern rockfall codes can be extended to incorporate such complex, but realistic forest boundary conditions.

Laboratory Study of Physical Barrier Efficiency for Worker Protection against SARS-CoV-2 while Standing or Sitting

Transparent barriers were installed as a response to the SARS-COV-2 pandemic in many customer-facing industries. Transparent barriers are an engineering control that are utilized to intercept air traveling between customers to workers. Information on the effectiveness of these barriers against aerosols is limited. In this study, a cough simulator was used to represent a cough from a customer. Two optical particle counters were used (one on each side of the barrier, labeled reference and worker) to determine the number of particles that migrated around a transparent barrier. Nine barrier sizes and a no barrier configuration were tested with six replicates each. Tests of these 10 configurations were conducted for both sitting and standing scenarios to represent configurations common to nail salons and grocery stores, respectively. Barrier efficiency was calculated using a ratio of the particle count results (reference/worker). Barriers had better efficiency when they were 9 to 39 cm (3.5 to 15.5 inches) above cough height and at least 91 cm (36 inches) wide, 92% and 93% respectively. Barriers that were 91 cm (36 inches) above table height for both scenarios blocked 71% or more of the particles between 0.35–0.725 µm and 68% for particles between 1 to 3 µm. A barrier that blocked an initial cough was effective at reducing particle counts. While the width of barriers was not as significant as height in determining barrier efficiency it was important that a barrier be placed where interactions between customers and workers are most frequent.

Protecting surface and buried structures from tunnelling using pile walls: a prediction model

When tunnelling poses excessive risks for buildings and buried foundations, a pile row barrier may shield the existing structure from ground movements. This paper presents a three-dimensional linear elastic prediction method to evaluate the protective action of pile walls against surface and subsurface ground movements due to new tunnels, both directly behind the wall as well as within the entire ground. Analyses are carried out to evaluate the vertical and horizontal movements of the ground and the pile wall as the result of soil-pile row interaction. New factors that quantify the wall efficiency in reducing settlements and deflections behind the wall are proposed; the results indicate that the effectiveness of the pile wall at reducing horizontal displacements is limited. Subsequently, predictions are compared against field and numerical data to demonstrate that the elastic solution is applicable, particularly for small ground losses. Finally, the barrier efficiency in reducing settlements is discussed comparing pile walls and diaphragm walls.

Study of acoustic characteristics of noise barriers

The acoustic efficiency of noise barriers has been studied using the developed two-dimensional finite element model in the COMSOL Multiphysics software package. Numerical calculations of the semi-infinite barrier efficiency have been compared with calculations conducted by the Maekawa formula. The main attention has been paid to the influence of the underlying surface on barrier acoustic characteristics. The barrier acoustic efficiency depends on its height, the position of the noise source and on the calculation point above the underlying surface. This dependence has been presented in this research.

Investigation of the effect of a noise barrier on a railway track in the Kysuce region

Purpose of the noise barriers is to create an acoustically sufficient impermeable obstacle located on the sound wave propagation path, thereby creating a shadow of the sound pressure level behind the barrier. The paper is focused on the analysis of measured noise values at specific selected points of the railway track in the region of Kysuce without noise barrier and on the determination of noise barrier efficiency. The observed values are compared with the permissible noise values specified by the Slovak legislation

The cuticle inward barrier in Drosophila melanogaster is shaped by mitochondrial and nuclear genotypes and a sex-specific effect of diet

An important role of the insect cuticle is to prevent wetting (i.e., permeation of water) and also to prevent penetration of potentially harmful substances. This barrier function mainly depends on the hydrophobic cuticle surface composed of lipids including cuticular hydrocarbons (CHCs). We investigated to what extent the cuticle inward barrier function depends on the genotype, comprising mitochondrial and nuclear genes in the fruit fly Drosophila melanogaster, and investigated the contribution of interactions between mitochondrial and nuclear genotypes (mito-nuclear interactions) on this function. In addition, we assessed the effects of nutrition and sex on the cuticle barrier function. Based on a dye penetration assay, we find that cuticle barrier function varies across three fly lines that were captured from geographically separated regions in three continents. Testing different combinations of mito-nuclear genotypes, we show that the inward barrier efficiency is modulated by the nuclear and mitochondrial genomes independently. We also find an interaction between diet and sex. Our findings provide new insights into the regulation of cuticle inward barrier function in nature.

ACOUSTIC RELIABILITY OF THE NOISE BARRIERS

A large amount of regulatory and technical documentation, from state standards to guidelines governing the requirements for noise barrier design and location, has been currently developed in Russia. However, despite such an abundance of regulatory and technical documentation, it is extremely difficult to achieve compliance between the theoretical and practical noise barrier efficiency. According to the study, in the 3rd year of operation, 7 out of 10 noise barriers have already lost their original acoustic properties, the state of 50% of the NB can be estimated as ‘moderate’, 20% - as ‘bad’. Starting from the 8th year of operation, the condition of 50% of the NB is characterized as ‘moderate’, and 50% - as ‘bad’. It is necessary to adjust the regulatory and technical documentation taking into account the main issues and errors encountered in practice.