The Hitchhiker’s Guide to Hydrogen Peroxide Fumigation, Part 2: Verifying and Validating Hydrogen Peroxide Fumigation Cycles

2020 ◽  
pp. 153567602092109
Author(s):  
Daniel Kümin ◽  
Monika Gsell Albert ◽  
Benjamin Weber ◽  
Kathrin Summermatter
Keyword(s):  
Hydrogen Peroxide ◽  
Relevant Literature ◽  
Biological Indicators ◽  
Physical Parameters ◽  
Technical Requirements ◽  
Chemical Indicators ◽  
Literature Searches ◽  
Personal Experiences ◽  
Long Time ◽  
Process Controls

Introduction: Part 1 of this two-part series describes the use of hydrogen peroxide as a fumigant and compares it with other fumigants on the market. Technical requirements are outlined while considering physical and biological limitations of the system. This second part focuses primarily on the use of process controls to verify and validate hydrogen peroxide fumigations. Finally, a model encompassing the entire fumigation process is presented. Methods: Part 2 of the series focuses on the authors’ long-time personal experiences in room and filter fumigation using various fumigation systems and is supplemented with relevant literature searches. Results: The reader is introduced to the planning and implementation of fumigation process validations. Biological indicators help users develop safe and efficient processes. Chemical indicators can be used as process controls, while measuring physical parameters will help avoid condensation of hydrogen peroxide. How many biological and chemical indicators and what type should be applied for cycle development are additionally explained. Discussion: It is important to consider numerous technical requirements when planning to implement hydrogen peroxide fumigation at an institution. Also, considerable thought needs to go into the verification and validation of the fumigation process. Conclusions: Part 1 of this series presents an overview of different fumigation systems based on hydrogen peroxide on the market and their technical requirements. Part 2 focuses on validation and verification of hydrogen peroxide fumigation while considering the entire fumigation process. The two parts together will serve users as a guide to establishing hydrogen peroxide fumigations at their facilities.

scholarly journals Preparation and properties of hybrid materials for high-rise constructions

2018 ◽  
Vol 33 ◽  
pp. 02075 ◽  
Author(s):  
Tatyana Matseevich
Keyword(s):  
Stress Relaxation ◽  
Epoxy Resin ◽  
Relaxation Process ◽  
Hybrid Materials ◽  
Mechanical Performance ◽  
Mechanical Relaxation ◽  
Physical Parameters ◽  
Quasi Equilibrium ◽  
High Rise ◽  
Long Time

The theme of the research is important because it allows to use hybrid materials as finishing in the high-rise constructions. The aim of the study was the development of producing coloured hybrid materials based on liquid glass, a polyisocyanate, epoxy resin and 2.4-toluylenediisocyanate. The detailed study of the process of stress relaxation at different temperatures in the range of 20-100°C was provided. The study found that the obtained materials are subject to the simplified technology. The materials easy to turn different colors, and dyes (e.g. Sudan blue G) are the catalysts for the curing process of the polymeric precursors. The materials have improved mechanical relaxation properties, possess different color and presentable, can be easily combined with inorganic base (concrete, metal). The limit of compressive strength varies from 32 to 17.5 MPa at a temperature of 20 to 100°C. The values σ∞ are from 20.4 to 7.7 MPa within the temperature range from 20 to 100°C. The physical parameters of materials were evaluated basing on the data of stress relaxation: the initial stress σ0, which occurs at the end of the deformation to a predetermined value; quasi-equilibrium stress σ∞, which persists for a long time relaxation process. Obtained master curves provide prediction relaxation behavior for large durations of relaxation. The study obtained new results. So, the addition of epoxy resin in the composition of the precursor improves the properties of hybrid materials. By the method of IR spectroscopy identified chemical transformations in the course of obtaining the hybrid material. Evaluated mechanical performance of these materials is long-time. Applied modern physically-based memory functions, which perfectly describe the stress relaxation process.

scholarly journals Methodical approaches to the evaluation of surface pollution of water objects in the area of mining enterprises (on the example of Donetsk-Pridniprovsk region)

2021 ◽  
Vol 39 (3) ◽  
pp. 69-75
Author(s):  
Olena Voloshkina ◽  
Olena Zhukova ◽  
Irina Korduba ◽  
Daniil Marshall
Keyword(s):  
Water Quality ◽  
Water Cycle ◽  
Surface Water Quality ◽  
Global Scale ◽  
Ecological Condition ◽  
Water Bodies ◽  
Anthropogenic Factors ◽  
Chemical Indicators ◽  
Quality Of Water ◽  
Long Time

The most important component of ecologically safe development of natural and socio-economic systems is the use of nature, which involves the organization of water resources, which ensures sustainable development and for a long time retains sufficient water potential. The ХХІ century is characterized by significant negative changes in the natural environment caused by the uncontrolled use of natural resources, the development of industry and transport, which leads to increased water consumption and at the same time increase its pollution. This has been particularly noticeable over the last 50 years, when human impact on the planet's water cycle has reached a global scale. Deterioration of the ecological condition of surface waters is due to qualitative and quantitative depletion of factors of their formation, which in some cases makes it impossible to use them for economic purposes. Water quality of water bodies is formed under the influence of both natural and anthropogenic factors. As a result of human activity in reservoirs many anthropogenic substances of various degree of toxicity can arrive. The article attempts to assess changes in surface water quality over the past decade and to determine the degree of natural and man-made transformation of rivers in the region and the possibility of their self-restoration and stabilization of the ecological danger of the region. The existing methods of assessment of water bodies by chemical indicators used in the area of operation of mining enterprises are considered. In some methods, the assessment of water bodies usually reflects regional features rather than their own pollution. Calculations for the water basin river Siverskyi Donets are made and relevant patterns are established.

A Head-to-Head Comparison of Hydrogen Peroxide Vapor and Aerosol Room Decontamination Systems

2011 ◽  
Vol 32 (9) ◽  
pp. 831-836 ◽  
Author(s):  
T. Holmdahl ◽  
P. Lanbeck ◽  
M. Wullt ◽  
M. H. Walder
Keyword(s):  
Hydrogen Peroxide ◽  
Cycle Time ◽  
New Technologies ◽  
Biological Indicators ◽  
The Other ◽  
Test Room ◽  
Cycle Times ◽  
Hydrogen Peroxide Vapor ◽  
In Vitro Comparison

Objective.New technologies have emerged in recent years for the disinfection of hospital rooms and equipment that may not be disinfected adequately using conventional methods. There are several hydrogen peroxide–based area decontamination technologies on the market, but no head-to-head studies have been performed.Design.We conducted a head-to-head in vitro comparison of a hydrogen peroxide vapor (HPV) system (Bioquell) and an aerosolized hydrogen peroxide (aHP) system (Sterinis).Setting.The tests were conducted in a purpose-built 136-m3test room.Methods.One HPV generator and 2 aHP machines were used, following recommendations of the manufacturers. Three repeated tests were performed for each system. The microbiological efficacy of the 2 systems was tested using 6-log Tyvek-pouchedGeobacillus stearo-thermophilusbiological indicators (BIs). The indicators were placed at 20 locations in the first test and 14 locations in the subsequent 2 tests for each system.Results.All BIs were inactivated for the 3 HPV tests, compared with only 10% in the first aHP test and 79% in the other 2 aHP tests. The peak hydrogen peroxide concentration was 338 ppm for HPV and 160 ppm for aHP. The total cycle time (including aeration) was 3 and 3.5 hours for the 3 HPV tests and the 3 aHP tests, respectively. Monitoring around the perimeter of the enclosure with a handheld sensor during tests of both systems did not identify leakage.Conclusion.One HPV generator was more effective than 2 aHP machines for the inactivation ofG. stearothermophilusBIs, and cycle times were faster for the HPV system.

Decision risk approach to the application of biological indicators in vapor phased hydrogen peroxide bio-decontamination

2018 ◽  
Vol 32 (4) ◽  
pp. e3015
Author(s):  
Éva Pusztai ◽  
Sándor Kemény ◽  
Emese Vágó ◽  
Anikó Horváth
Keyword(s):  
Hydrogen Peroxide ◽  
Biological Indicators ◽  
Risk Approach

Dissosiativ identitetsforstyrrelse i utredning av barn og ungdom: Teori og kliniske utfordringer

2021 ◽  
Vol 58 (8) ◽  
pp. 672-680
Keyword(s):  
Clinical Practice ◽  
Relevant Literature ◽  
Dissociative Disorders ◽  
Cognitive Difficulties ◽  
Dissociative Symptoms ◽  
Literature Searches ◽  
Adequate Understanding ◽  
Assessment And Treatment ◽  
Trauma Model ◽  
Practice Methods

Background: Clinical practice and recent research indicate that dissociative symptoms and disorders are left unidentified and undiagnosed by health professionals. Based on a clinical case from our work setting, this article describes relevant literature regarding dissociation and dissociative disorders to add to the knowledge of the theoretical and phenomenological features of complex dissociative disorders. Further, we describe differential diagnostic challenges that may arise in clinical practice. Methods: Both systematic and non-systematic literature searches were performed. Findings: Recent research shows the Trauma model to be central to understanding dissociative disorders. Symptoms can be mistaken for cognitive difficulties, oppositional issues or other somatic symptoms. Quantitative measures, systematic observations and clinical evaluations are fundamental for identifying dissociative symptoms and disorders. Implications: There is potential for identifying and evaluating dissociative symptoms at an earlier stage. Interdisciplinary and differential diagnostic evaluations are crucial to provide adequate understanding, assessment, and treatment of these patients. Keywords: Dissociative identity disorder, dissociation, somnambulism, biopsychosocial framework, clinical practice

scholarly journals Application of Fundamental Models for Creep Rupture Prediction of Sanicro 25 (23Cr25NiWCoCu)

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 638
Author(s):  
Junjing He ◽  
Rolf Sandström
Keyword(s):  
Grain Boundary Sliding ◽  
Empirical Models ◽  
Creep Rupture ◽  
Solid Solution Hardening ◽  
Physical Parameters ◽  
Brittle Creep ◽  
Creep Cavitation ◽  
Long Time ◽  
Boundary Sliding ◽  
Term Creep

Creep rupture prediction is always a critical matter for materials serving at high temperatures and stresses for a long time. Empirical models are frequently used to describe creep rupture, but the parameters of the empirical models do not have any physical meanings, and the model cannot reveal the controlling mechanisms during creep rupture. Fundamental models have been proposed where no fitting parameters are involved. Both for ductile and brittle creep rupture, fundamental creep models have been used for the austenitic stainless steel Sanicro 25 (23Cr25NiWCoCu). For ductile creep rupture, the dislocation contribution, solid solution hardening, precipitation hardening, and splitting of dislocations were considered. For brittle creep rupture, creep cavitation models were used taking grain boundary sliding, formation, and growth of creep cavities into account. All parameters in the models have been well defined and no fitting is involved. MatCalc was used for the calculation of the evolution of precipitates. Some physical parameters were obtained with first-principles methods. By combining the ductile and brittle creep rupture models, the final creep rupture prediction was made for Sanicro 25. The modeling results can predict the experiments at long-term creep exposure times in a reasonable way.

scholarly journals Preliminary Qualitative Findings: Challenges in Large Infrastructure Projects towards Development of Innovative Performance Measurement

2015 ◽  
Vol 773-774 ◽  
pp. 1012-1016
Author(s):  
Md. Asrul Nasid Masrom ◽  
Mohd Hilmi Izwan Abd Rahim ◽  
Sulzakimin Mohamed ◽  
Riduan Yunus
Keyword(s):  
Performance Measurement ◽  
Relevant Literature ◽  
Performance Measurement System ◽  
Infrastructure Projects ◽  
Innovative Performance ◽  
Technical Requirements ◽  
Project Outcome ◽  
Project Objectives ◽  
Key Participants ◽  
Managerial Capabilities

Performance measurement system to assess development of large infrastructure project has developed due to the unachieved of high design and technical requirements, excessive cost investments and lack of competent human resources and managerial capabilities. Growing numbers of discrepant of interest among key participants has also led to conflicts, blame cultures, and mismatches of objectives that have been found to be contributory factors to poor project performance. Although, several approaches have been determined, the challenges in terms of time, cost, and quality (objective measures) are still arguable. Further exploration requires the inclusion of additional challenges in delivering large infrastructure projects, particularly in relation to subjective measures, such as safety, relationship, satisfaction, social and environmental aspects. Owing to this limitation, preliminary findings of identification challenges in large infrastructure projects are vital to fulfill the current needs in the development of innovative performance measurement. The research adheres to by reviewing relevant literature and evaluating expert insights on the research topic. The results of the research would provide qualitative evidence in support of the notion that appropriate and comprehensive performance measurement to improve project outcome. This study may also encourage key stakeholders mainly involved in infrastructure projects to increase their attention on possible challenges to achieve project objectives and requirements in the development of a large project, and helps to the achievement of government transformation programme (GTP).

scholarly journals On the function of chlorophyll

1915 ◽  
Vol 89 (609) ◽  
pp. 1-17 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Peroxide ◽  
Radiant Energy ◽  
Hexose Sugars ◽  
Lime Water ◽  
Long Time

It has been generally assumed that the function of chlorophyll is to absorb radiant energy from light and to render this available for the production of formaldehyde from carbon dioxide and water, the formaldehyde being subsequently polymerised to carbohydrates, and oxygen being set free. This is supported by the fact that chlorophyll contains magnesium and that in a cold watery solution of carbon dioxide this metal produces formaldehyde, which readily polymerises spontaneously to paraformaldehyde, C 2 H 4 O 2 , or metaformaldehyde, C 3 H 6 O 3 , and into hexose sugars in the presence of lime-water or other weak alkali. Usher and Priestly stated that chlorophyll films when exposed to sunlight decomposed carbon dioxide, producing formaldehyde and hydrogen peroxide. The latter was responsible for the bleaching of chlorophyll in sunlight, and if a “katalase” enzyme was present the oxygen was set free and the chlorophyll remained green. “The bleaching of the chlorophyll in sunlight whether carbon dioxide is present or not is due to the formation of hydrogen peroxide.” As a matter of fact chlorophyll films immersed in a solution of hydrogen peroxide remain green for a long time in darkness, and when exposed to light do not bleach much more rapidly than similar films exposed to ordinary air.

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