Requirements Of ISO Research Articles

Monitoring of the Analytical Performance of Four Different Blood Glucose Monitoring Systems: A Post-market Performance Follow-Up Study.

A sizeable minority of commercially available blood glucose monitoring (BGM) systems fail to satisfy regulatory accuracy requirements, such as ISO 15197:2013, after approval. This study assessed whether the BGMs tested could consistently meet these ISO requirements by investigating their accuracy in a non-standardized setting. In this 18-month post-market performance study, using the ISO criteria, healthcare professionals tested the accuracy of four CE-marked BGM systems (Roche Diabetes Care, Mannheim, Germany) on European adults with diabetes mellitus. ISOcriteria included 95% of blood glucose (BG) values being within ± 15mg/dl of a reference measurement for BG < 100mg/dl or ± 15% for BG ≥ 100mg/dl and, in the Parkes Consensus Error grid for type 1 diabetes comparing capillary BGM measurements versus reference method, 99% of BG values falling within zone A (no effect on clinical action or outcome) and zone B (altered clinical action with little or no effect on clinical outcome). BGM readings were obtained from 1650 participants, and the number of readings per BGM system was between 1712 and 2376. The percentage of BGM readings that fell within ISO 15197:2013 limits ranged from 99.4 to 99.9%. For all meter types, 100% of data points fell within zone A or zone B, and most data points for each meter (≥ 99.9%) were in zone A. All four CE-marked BGM models showed results within the accuracy limits defined by ISO 15197 in a non-standardized setting and thus consistently met regulatory accuracy requirements.

A prototype photoplethysmography-based cuffless device shows promising results in tracking changes in blood pressure

IntroductionNon-invasive cuffless blood pressure devices have shown promising results in accurately estimating blood pressure when comparing measurements at rest. However, none of commercially available or prototype cuffless devices have yet been validated according to the appropriate standards. The aim of the present study was to bridge this gap and evaluate the ability of a prototype cuffless device, developed by Aidee Health AS, to track changes in blood pressure compared to a non-invasive, continuous blood pressure monitor (Human NIBP or Nexfin) in a laboratory set up. The performance was evaluated according to the metrics and statistical methodology described in the ISO 81060-3:2022 standard. However, the present study is not a validation study and thus the study was not conducted according to the ISO 81060-3:2022 protocol, e.g., non-invasive reference and distribution of age not fulfilled.MethodData were sampled continuously, beat-to-beat, from both the cuffless and the reference device. The cuffless device was calibrated once using the reference BP measurement. Three different techniques (isometric exercise, mental stress, and cold pressor test) were used to induce blood pressure changes in 38 healthy adults.ResultsThe mean difference (standard deviation) was 0.3 (8.7) mmHg for systolic blood pressure, 0.04 (6.6) mmHg for diastolic blood pressure, and 0.8 (7.9) mmHg for mean arterial pressure, meeting the Accuracy requirement of ISO 81060-3:2022 (≤6.0 (10.0) mmHg). The corresponding results for the Stability criteria were 1.9 (9.2) mmHg, 2.9 (8.1) mmHg and 2.5 (9.5) mmHg. The acceptance criteria for the Change requirement were achieved for the 85th percentile of ≤50% error for diastolic blood pressure and mean arterial pressure but were higher than the limit for systolic blood pressure (56% vs. ≤50%) and for all parameters for the 50th percentile (32%–39% vs. ≤25%).ConclusionsThe present study demonstrated that the cuffless device could track blood pressure changes in healthy adults across different activities and showed promising results in achieving the acceptance criteria from ISO 81060-3:2022.

Analysis of The Main NBR-ISO Standards in The Implementation of An Integrated Management System For Environment, Health, and Occupational Safety

Purpose: This research aims to provide companies with valuable insights into the implementation of an Integrated Management System (IMS), offering a straightforward and practical approach that addresses both environmental and occupational safety aspects. Design/methodology/approach: This study is based on qualitative research aimed at exploring and analyzing Management Systems to gain a deeper understanding of the requirements of the NBR ISO 14001:2015 and NBR ISO 45001:2018 standards. It emphasizes the use of the SWOT analysis (Strengths, Weaknesses, Opportunities, and Threats) to identify areas for organizational improvement, along with the PDCA cycle (Plan - Do - Check - Act) as a strategic tool for system control and continuous improvement. Additionally, the study investigates the key factors that facilitate or hinder the implementation of these standards using the Root Cause Analysis method. Findings: An analysis of the NBR ISO 14001:2015 and NBR ISO 45001:2018 standards in the implementation of an IMS revealed that the SWOT matrix and the PDCA cycle are essential tools for effective planning. The study concludes that successful system implementation requires not only a thorough understanding of the standards' criteria but also a robust organizational culture that supports compliance and continuous improvement. Discussion: Management systems based on the NBR ISO 14001:2015 and NBR ISO 45001:2018 standards have experienced growing market demand. Implementing these systems is crucial for maintaining a company's competitiveness. However, the complexity of their structure and the associated high costs present significant barriers for many organizations, limiting their ability to compete with more established firms.

Design solutions to optimise acoustic requirements for specific work activities in open-plan offices

A high level of concentration is required in open-plan offices, which entails an optimized acoustic environment. The aim is to create a fit-employee environment in which speech privacy is guaranteed without compromising the sense of cooperation among occupants. The purpose of this study is to investigate the design solutions which optimize the acoustic requirements of ISO 3382-3 for a specific work activity defined in ISO 22955, such as non-collaborative work, collaborative work between people and mixed between collaborative and non-collaborative. The case study is one open-plan office occupied by 12 workers, which was not compliant with the standard. Acoustic measurements were used to calibrate the acoustic model in the Odeon software. Two screen and cubicle heights, three types of ceilings and two wall absorption configurations have been tested in a matrix of solutions for the office in the simulation model. This allowed us to investigate the design solutions that guarantee optimal values for the acoustical parameters chosen for each specific activity.

B-132 Within limits - is my thyroid just plump, or are these reference intervals telling me something?

Abstract Background Replacing immunoassay equipment brings challenges in the implementation of reference intervals (RIs). In 2023, Cork University Hospital (CUH) replaced Abbott Architect immunoassay analysers with Beckman Coulter DxI 9000 units. The manufacturer’s recommended reference intervals were applied as the DxI 9000 is new to the market. CUH reports ≈100,000 immunoassay results per month. Methods A minimum of 45 adult patient samples were run on the Abbott and Beckman Coulter platforms for each of sixteen analytes as part of method verification following the requirements of ISO 15189 and CLSI. The slope and intercept of the Passing-Bablok regression analyses were used to transform the Abbott RI and the newly modelled RIs compared to those provided by Beckman Coulter. Results Conclusions: While the manufacturer’s RI was adopted initially, the modelled data have shown that for three analytes (PTH, HCG, Free T4) the modelled RI differs significantly from the manufacturer’s. This was judged by how patients would theoretically be classified. For these assays it is necessary to closely monitor patients in the initial three months post-go-live to ensure that the RIs are clinically acceptable. A comprehensive dialogue was undertaken with clinicians before and after the implementation to ensure they were aware of the changes. All modelling was performed on adult patient data. However, CUH has a large paediatric patient cohort, and for this group, the same RI transformations were performed, and discussions were held with paediatric teams. Introducing new platforms and RIs requires careful planning, education and an open dialogue with clinicians to ensure no compromise to patient care. RIs should be reviewed frequently for appropriateness.

FUNDAMENTALS OF QUALITY ASSURANCE IN THE HIGHER EDUCATION SYSTEM

This study explores the critical issue of quality assurance in higher education systems, both in Kazakhstan and globally, where universities operate in a «consumer market» with students selecting educational programs, institutions, and resources. Based on an analysis of international and domestic research, the study aims to identify the foundations of quality assurance in higher education. The authors highlight key aspects of higher education quality, including student quality, teaching characteristics, academic regulations, and administrative support. Educational quality is examined within the context of international standards as a matter of national importance, with education levels serving as a foundation for economic development of both state and society. The research analysis reveals that various approaches, methods, and criteria for quality management are employed in creating systems for ensuring and assessing the quality of higher education institutions in Kazakhstan and abroad. These include the evaluative method of university activity quality management (SWOT analysis), Total Quality Management (TQM) strategy, and an approach based on the requirements of international quality standards ISO 9000:2000. The study notes that Kazakhstan has adopted a management model based on the ISO 9000:2000 international quality standards. This comprehensive review contributes to the understanding of quality assurance mechanisms in higher education and their implications for educational policy and practice.

The concept of microfiltration of hydraulic oil in rail vehicles

The article presents the issue of microfiltration of hydraulic oil from metallic impurities and water that deteriorate the properties of the oil. Tests carried out on oils have shown that periodic oil replacement in machines or vehicles in accordance with their maintenance documentation ensures that the system is emptied of 95% of impurities from the old oil before pouring the new one. The remaining part, i.e. 5% of impurities, together with the oil remaining on the walls of the pipes or inside other hydraulic devices, will mix with the new oil, reducing its cleanliness class. Periodic replacement of hydraulic oil will not allow for complete cleaning of the system. In extreme cases, poor oil condition may cause disruptions in the operation of the machine with the hydraulic system or its downtime for oil replacement or repair. Filtering the oil in the system while the machine is running will clean the oil from impurities and water, extend the oil's service life, without disabling the hydraulic system. The article includes, among others: The justification for the use of microfiltration of hydraulic oil with portable filtering devices in order to extend the service life of the oil until the next replacement is presented. The main purpose of the article is to present the methodology for testing hydraulic oil in accordance with the requirements of ISO, NAS and SAE in order to assign the oil to a given cleanliness class. Additionally, the results of testing the oil cleanliness class in various periods of operation of the machine with the hydraulic installation on a portable measuring device were presented.

An overview of Synlab SDN Biobank’s quality control system

Biobanks are valuable service units that ensure the usage of high-quality biological samples. They contribute to translational research, and their support may improve future therapeutic approaches. They store biological samples that can be used to examine circulation biomarkers, immune cells, and immunohistochemistry aspects of illnesses and further in-depth examinations using NGS techniques. The IRCCS Synlab SDN Biobank has about 70,000 well-preserved cryopreserved human samples from various diseases, primarily oncological but also neurological and cardiovascular. These biospecimens were taken from 25,000 participants underwent imaging with a contrast agent. The goal is to propose quality control assays that meet the requirements of the international standard ISO 9001:2015 and ISO 20387:2020 accreditation. PBMCs viability was determined, and immune subset cells were analyzed by flow cytometry. Furthermore, the expression of ubiquitous miRNAs was used to assess plasma sample integrity. The quality controls demonstrated that the biological samples were correctly cryopreserved; the preservation of human biological samples did not affect the quality of the biological samples tested. Indeed, the cryopreserved PBMCs had a vitality of more than 80%, and the lymphocyte subsets could be selected for future immune cell investigations. Furthermore, miRNA expression was highest in thawed plasma samples compared to the positive and negative controls. We evaluated the quality of our randomly selected biobank-thawed human samples. Both PBMCs and plasma samples fulfill the high-quality standards needed for biomedical research, assuring their long-term preservation. However, further research is needed in the biobanking field to establish globally accepted procedures to confirm the quality of biological samples.

Water Sorption and Solubility of Highly Aesthetic Single-Shade Nano-Hybrid Resin Composites.

Background A single-shade resin composite is a new type of resin composite that was introduced in 2019. There is not much data regarding the water sorption (Wsp) and water solubility (Wsl) of this type of resin composite. Therefore, this study aimed to investigate Wsp and Wsl and their effects on the surface roughness of a single-shade nano-hybrid resin composite in comparison with a conventional nano-hybrid resin composite in accordance with ISO 4049:2019 (Dentistry - Polymer-based Restorative Materials). Material and methods An in vitro study was performed to investigate the Wsp and Wsl of a single-shade supra-nano-hybrid composite (Omnichroma) and a conventional nano-hybrid composite (Filtek™ Z250 XT) in accordance with ISO 4049:2019. Five disks were prepared of each material with dimensions of 15 ± 1 mm in diameter and 1 ± 0.1 mm in thickness, as per ISO 4049:2019. The results were calculated according to the ISO equations for Wsp and Wsl in µg/mm3. Atomic force microscopy (AFM) was used to analyze the surface roughness (Ra) of test specimens. Results The findings showed that the values of Wsl and Wsp of both materials are comparable and revealed no statistically significant difference (P > 0.05). The AFM images showed a higher Ra post-solubility testing, and the statistical analysis indicated a significant difference for both materials. Conclusions The study concluded that the single-shade resin composite (Omnichroma) and the conventional nano-hybrid composite (Filtek™ Z250 XT) are following the requirements of ISO 4049:2019. The AFM analysis indicated that resin composite surfaces are significantly affected when exposed to water for a prolonged period of time. However, the Ra variations of Filtek™ Z250 XT were higher than Omnichroma specimens. These results indicate that resin composite surfaces can be significantly impacted by prolonged water exposure. This knowledge is critical for enhancing the long-term clinical performance and durability of these dental restorative materials.

Organization of reviews of a pharmaceutical enterprise quality management system functioning

Aim. To determine the state of organizing the process of analyzing the quality management system of a typical pharmaceutical enterprise in accordance with the current industry requirements of Good Manufacturing Practice and the ISO 9001:2015 standard, as well as substantiating effective approaches to improving this activity. Materials and methods. We used analysis, comparison, questionnaires, surveys and direct observations. The results were processed and verified using licensed Microsoft Office Excel software products. Results. The relevance of the development of quality management systems (QMS) of domestic pharmaceutical organizations in the period of martial law has been proven. The requirements of the DSTU ISO 9001:2015 standard, as well as the requirements of the guidelines on Good Manufacturing Practice (GMP) of medicines for reviewing and analyzing QMS of pharmaceutical enterprises (PhE) have been analyzed. Approaches to the organization of QMS review at a number of domestic PhE have been studied; as a result, typical inconsistencies of these procedures have been determined. Based on the results of the study and the experience analyzed in supporting the QMS functioning of PhE, effective organizational approaches have been identified, and recommendations are given for the effective analysis of QMS of PhE. Conclusions. In the study conducted, a review of the practice of analyzing QMS at a number of domestic and foreign PhE has been carried out, and typical inconsistencies of this process have been identified and systematized. The requirements of the DSTU ISO 9001:2015 standard, as well as the industry requirements of the GMP guidelines for reviewing and analyzing the quality system of PhE have been analyzed. Based on the results of the research and the authors’ own experience in implementing and supporting the QMS functioning of PhE, the main organizational approaches and recommendations for analyzing QMS of PhE have been determined.

Evaluation of Multi-Crop Biofuel Pellet Properties and the Life Cycle Assessment

Although wood biomass is mostly used to produce solid biofuel pellets, it is important to evaluate the possibilities of using other types of biomass as well. It is not only important to obtain biofuel pellets of suitable quality but also to ensure a sustainable process of producing and using these pellets for energy production. This paper presents an evaluation of the quality characteristics of seven different biofuel pellets made from multi-crop plants (fibrous hemp, maize, and faba bean) and a life cycle assessment (LCA) of the heat production by burning these pellets. The physical-mechanical properties and elemental composition of the pellets are determined according to international standards, as indicated in the methodology section. The LCA was performed using the SimaPro 9.5 software. The complete life cycle from cradle-to-grave is assessed, i.e., from growing plants to spreading ash obtained from pellet burning. An analysis showed that in most cases the produced pellets met the requirements of the standard ISO 17225-6:2021. The lowest negative environmental impact associated with the production of 1 GJ of thermal energy was for pellets made from fibrous hemp and maize biomass (MIX2-1) and pellets made from fibrous hemp and faba bean biomass (MIX2-3). Production of pellets from maize biomass (S-Mz) was found to have the highest carbon footprint (29.1 CO2eq GJ−1) and was associated with the lowest crop yield compared to the other six scenarios.

Sound absorption uncertainty in small reverberation chambers

Manufacturers in the mobility industry typically measure and specify the sound absorption coefficient of materials using a small reverberation chamber according to SAE J2883. These chambers have a 6 to 25 cubic meter volume, use a 1.0 meter x 1.2 meter sample size and report sound absorption in the one-third octave bands from about 400 Hz to 10,000 Hz. This is in contrast to a full-size chamber built to satisfy the requirements of ASTM C423 or ISO 354, which have about a 200 cubic meter volume, use a 2.4 x 2.7 or 3.2 x 3.2 square meter sample size and report sound absorption in one-third octave bands from 100 to 5,000 Hz. Although the room and sample size dimensions scale, many of the factors that contribute to uncertainty in the measurement do not scale. These include relative humidity, temperature, and other physical measurements and if the same instrumentation is used, microphone calibration and measurement uncertainty in the higher frequency range. This paper examines the potential measurement uncertainty in these chambers over the 400 to 10,000 Hz frequency range and compares this to past uncertainty analyses of full-size chambers over a similar frequency range.

Assessment of the quality of the labour safety management system in accordance with the requirements of the international standard ISO 45001:2018 at the stage of operation

The subject matter of the article is the assessment of the quality of the occupational safety management system. The goal of the article is to develop a methodology for assessment of the occupational safety management system at the stage of operation. The article solves the following task: to investigate the possibility of applying methods for analysing the dynamic characteristics of the occupational safety management system and to develop algorithms and methods for using the criteria of non-parametric statistics. Methods are used: qualimetry and mathematical statistics. The following results were obtained: an analysis of the requirements of the international standard ISO 45001:2018 was carried out to determine the need to monitor, measure and analyse the functioning of the occupational safety management system, which revealed that the effectiveness of the development and implementation of the occupational safety management system depends on the assessment methodology. An analysis of existing research and publications on the evaluation of processes, including those related to occupational safety, is carried out. The methods for evaluating mathematical systems for processing and controlling gross errors and stationarity, which are key to the analysis of occupational safety management processes, are considered. Non-parametric criteria for checking the stationarity of random processes are considered in detail. Sequences of means and means squares are compared with expected values to determine whether rejections of the stationary hypothesis are justified. The expediency of using these methods for analysing occupational safety management systems is determined. The dynamic nature of the processes and the importance of monitoring and data analysis to ensure effective safety management practices are analysed. Conclusions: The application of methods for analysing the dynamic characteristics of the occupational safety management system is substantiated and algorithms and methods for using the criteria of non-parametric statistics are developed, which allow to obtain an assessment of the system, taking into account the limited information about its indicators and the lack of knowledge of the law of their distribution as a random variable.

ОЦЕНКА ТОЧНОСТИ АВТОМАТИЧЕСКОГО СФИГМОМАНОМЕТРА С МАНЖЕТОЙ «360°» ПРИ ИЗМЕРЕНИЯХ У ВЗРОСЛЫХ ЛЮДЕЙ С ОКРУЖНОСТЬЮ ПЛЕЧА 22 САНТИМЕТРА И МЕНЕЕ

To validate a blood pressure (BP) monitor according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard (ISO 81060-2:2018) in a special population of adults with an upper arm circumference of 22 cm or less 37 subjects were recruited. Sphygmomanometer “Armed” identical to previously validated in the general population group YuWell YE660E was used with a “360°” cuff designed for an upper arm circumference of 18 – 36 cm. Sequential measurements of BP were obtained using the test device and the standard mercury sphygmomanometer. A total of 108 sets of comparison data were obtained and analyzed. According to the validation criterion 1, the mean ± SD of the differences was 8.00 ± 6.30 / -16.11 ± 5.15 mmHg. In this special group “Armed” YE660E with “360°” cuff do not meet the requirements of ISO 81060-2:2018.

ОЦЕНКА ТОЧНОСТИ АВТОМАТИЧЕСКОГО СФИГМОМАНОМЕТРА С МАНЖЕТОЙ ДИАПАЗОНА «17-22» ПРИ ИЗМЕРЕНИЯХ У ВЗРОСЛЫХ ЛЮДЕЙ С ОКРУЖНОСТЬЮ ПЛЕЧА 22 САНТИМЕТРА И МЕНЕЕ

To validate a blood pressure (BP) monitor according to the Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Universal Standard (ISO 81060-2:2018) in a special population of adults with an upper arm circumference of 22 cm or less 37 subjects were recruited. The previously validated in general population OMRON M2 Basic (HEM-7121) was used with a HEM CS24 cuff designed for an upper arm circumference of 17–22 cm. Sequential measurements of BP were obtained using the test device and the standard mercury sphygmomanometer. A total of 108 sets of comparison data were obtained and analyzed. According to the validation criterion 1, the mean ± SD of the differences was -7.81 ± 5.20 / -10.66 ± 5.48 mmHg. In this special group HEM-7121 and HEM CS24 do not meet the requirements of ISO 81060-2:2018.

Comparative Study of the Reactivity of Animal-Derived Blood on Medical Device Materials using Hematology and Platelet Activity Tests

In accordance with the requirements of ISO 10993-4, we established the feasibility of conditions for animal blood application in vitro to identify substances that induce thrombus formation and confirmed the differences in blood reactivity between animals necessary for interpreting in vivo results in this study. To this end, differences in the response of rabbit, pig, and monkey blood to each anticoagulant presented in ASTM F2888-19 were tested. It was confirmed that the direct heparinization method had a higher test sensitivity than that of recalcified sodium citrate, thus distinguishing thrombotic substances regardless of the test species. Particularly in pig blood, platelet and white blood cell counts showed the greatest decrease after reactions with various test materials. Expression of β-TG and PMN-elastase, indicators for platelet and leukocyte activities, was confirmed in pig blood when reacted with various test materials. A decrease in platelet count and significant increase in β-TG were observed in the black rubber test group, which was the positive candidate material. Conversely, a decreased leukocyte count was confirmed, but an increase in the expression of PMN-elastase was not observed. This result satisfied the ISO 10993-4 criteria for determining a positive thromboembolic substance. This study provided additional information on the selection of anticoagulants for the design of trials and selection of animal species for evaluating thrombosis formation on medical device materials by using the methods described in ISO 10993-4 and ASTM F2888-19.

Gap Analysis of the Environmental Management System Performance of PT. XXX to ISO 14001:2015 Standard

PT. XXX is one of the oil and gas exploration companies in Indonesia operating in the Rokan Block of the Duri Steam Flood (DSF) Operation Area. To maintain the level of petroleum production in operation, PT. XXX DSF Operating Area adds oil and gas wells, improves, and improves operation reliability through upgrading several existing facilities; seen from the environmental setting at the current operational location, DSF's operational area activity plan has an impact on environmental components. To mitigate it, PT. XXX has developed an Environmental Management System (EMS) DSF Operating Area according to the international standard ISO 14001:2015. This quantitative descriptive research aims to determine the gap in QMS performance implemented by companies with ISO 14001: 2015 standards using seven clauses: Self-Assessment Checklist Internal Audit ISO 14001: 2015 GEMI 2015. To find out the Company's SML gap score with ISO 14001: 2015 standard is determined by the Gap Analysis method. The gap results from the 7 (seven) clauses analysed to show the readiness score of SML PT. XXX DSF operational to implement ISO 14001:2015 Standard is 98.83% refers to range gap analysis if the score range of 75% - 100% indicates PT. XXX DSF Operations is ready to complement EMS ISO 14001:2015 and carry out certification. The gap score between the Company's Environmental Management System (EMS) that is being implemented and the ISO 14001:2015 standard is 1.17%. The gap in clauses that have not met the requirements of SML ISO 14001: 2015 is Clause Support, which scores 95% and Clause Performance Evaluation, which scores 96%.

Approaches for the production of reference materials with qualitative properties—The new International Standard ISO 33406

The number of reference materials (RMs), including certified reference materials (CRMs) characterized for qualitative properties, has steadily increased in recent years. In response, the Technical Committee for Reference Materials of the International Organization for Standardization, ISO/TC 334, developed ISO 33406 to provide guidance to reference material producers (RMPs) on producing qualitative RMs. ISO 33406 builds on the general requirements in ISO 17034:2016 for RMP competence and offers specific guidance on value assignment, assessment of homogeneity and stability, statement of metrological traceability, and measurement uncertainty evaluation for RMs with qualitative property values.

Assessment of the occupational health and safety management system by qualimetric methods

Abstract Requirements of the international standard ISO 45001:2018 were analysed to identify the need for monitoring, measuring and analysing the functioning of the occupational health and safety management system. This analysis has made it clear that the effectiveness of the development and implementation of the occupational health and safety management system depends on the assessment methodology. The study focused on existing studies and publications on the assessment of processes, including those related to occupational safety, assessment methods or qualitative methods, and statistical methods used for assessment. As a result, the topic has been proven relevant, and the goal of the article was determined: to study the possibility of using qualimetric methods for evaluating the labour safety management system. A survey was conducted among workers at a machine-building enterprise to evaluate the occupational health and safety management system. Verbal scales were proposed to process the study results as they allow quantitative ratings to be obtained on the coded scale of the desirability function. The study result is a technique for obtaining a quantitative assessment of the occupational health and safety management system. This technique is universal and can be applied to any enterprise. It can also be used to make managerial decisions regarding the improvement of the occupational health and safety management system.

Акустические характеристики пористого алюминия, применяемого для изготовления шумопоглощающих устройств промышленного оборудования

Noise-absorbing devices made of porous aluminum have been used as components of units and systems of modern industrial equipment (pressure regulators, compressors, exhaust systems, pneumatic tools, heat engines, etc.). The advantages of products made of the material are high mechanical strength, resistance to chemicals, vibrational and thermal loads, and recyclability. Noise absorption in the structure of porous aluminum is caused by the loss of energy as a result of viscous friction and heat exchange between oscillating air particles and the skeleton of the material. Structural parameters of porous metals significantly affect the efficiency of noise absorption. Experimental studies of sound-absorbing properties of porous aluminum samples of different thicknesses, porosity, and pore sizes have been carried out for the present paper. An acoustic impedance tube, in compliance with the requirements of ISO 10534 and ASTM E1050 on 5–20 mm thick samples, has been used for the study. The porosity of samples was 0.5–0.7, whereas the average pore size was equal to 0.6–2 mm. Two variants of sample installation have been investigated, i.e., without an air gap and with the formation of a 20 mm air gap relative to the surface of the rigid piston of the impedance tube. The impact of structural parameters and thickness of porous aluminum samples on their noise-absorption properties has been assessed based on the results of the study. It has been determined that the increase of average pore size within the range between 0.6 and 2 mm causes the reduction of the noise-absorption coefficient. The effect becomes more pronounced when a sample with the formation of an air gap relative to the piston surface is installed. With identical average pore sizes and thicknesses, the highest values of sound absorption coefficient by the porous aluminum samples have been registered for a porosity of 0.6. The study results can be used for the development and modernization of sound-absorbing devices for industrial equipment made of porous aluminum.