Established Testing Procedures Research Articles

Method for accelerated testing of wind turbine gearbox bearings based on frictional energy in the rolling contact

This paper investigates a method for a novel accelerated test procedure for rolling bearings in wind turbine gearboxes. Established test procedures e. g. highly accelerated lifetime tests (HALT) mainly reflect fatigue damage and not slip-induced damage patterns (e.g. smearing). A commonly used criterion to rate the severity of an operating point regarding slip-induced damage is the frictional energy. Frictional energy is introduced into the rolling contact as soon as there is a significant combination of simultaneously occurring slip and pressure. Up to now only critical thresholds for this criterion that must not be exceeded have been identified on small-scale component test rigs. However, the permissible amount and duration of overshoots of the critical threshold that lead to damage in the actual application are not understood yet. Therefore, the aim is to conduct tests on full-size test rigs in which frictional energy is applied until slip-induced damage occurs. In order to perform these tests in a reasonable time, it is essential to accelerate the test procedures. Thus, this paper introduces a method for accelerated test procedures based on frictional energy in the rolling contact. The requirement is that the same cumulated frictional energy as in field operation is applied in a shorter time on the test rig. A further requirement is that the frictional power in the accelerated test procedure never exceeds the maximum frictional power occurring in the field. This paper shows the theoretical background regarding frictional energy and the transfer to the test procedure.

Combustion and emission characteristics of distilled waste plastic pyrolysis oil-gasoline blends using single cylinder motorcycle petrol engine

ABSTRACT This study assessed the performance and emissions characteristics of a single cylinder, 2-stroke motorcycle spark ignition engine (Esoo 150 cc) utilising clay-catalytically produced distilled waste plastic pyrolysis oil (DWPPO) fuel. The clay catalyst and fuel properties were analysed using established standard testing procedures. The engine performance and exhaust gas emissions were determined for various fuel blends and compared with those of commercial gasoline at various parameters. Results showed that distilled pyrolysis fuel properties (kinematic-viscosity: 6.4 × 10–7 m2/s; caloric-value: 47.82 MJ/kg) were enhanced compared to kinematic viscosity of 1.92 × 10–6 m2/s and caloric value of 44.41 MJ/kg for Crude Waste Plastic Pyrolysis Oil. Notably, chemical composition of distilled fuel collected within a temperature range of 90°C-180°C closely resembled those of pure gasoline. It was also shown that 50% Distilled Waste Plastic Pyrolysis Oil (D50WPPO) significantly improved the brake power, brake thermal efficiency and reduction in brake specific fuel consumption while operating at full load conditions with various DWPPO-Gasoline blends and pure gasoline. Unburned hydrocarbon emissions reduced by 40% when the engine was fuelled with D50WPPO. The study concluded that DWPPO can potentially be employed as a substitute of conventional gasoline without any engine modifications.

VALIDATING THE IMPACT OF THE COMPREHENSIVE MOBILITY EVALUATION TOOL USED BY NURSES IN ACUTE CARE

Abstract Existing nursing-based mobility tools were developed with clinical and reliability testing with small samples; none focused on predicting assistance needs. The Comprehensive Mobility Evaluation Tool (CMET) was designed using established testing procedures to support nurses to assess all phases of mobilization and predict level of assistance. A prospective descriptive research design was used to test reliability and validate CMET items, scoring, and ability to predict LOA. A randomly selected sample of decisional/English-speaking non-ventilated stable patients were enrolled from four medical/surgical and one critical care units at a large community hospital where CMET was used. Trained data collectors consented patients, completed bedside testing, and distributed patient surveys. Descriptive, inferential, and regression statistics were used for analysis. The representative sample (N=190) had an average age of 67.3 yrs (SD=16.2, 23-101), 50% male, with a robust range of mobility levels. Inter-rater reliability (n=27) yielded an average kappa of 0.94. Six of seven steps contributed significantly to predicting patient LOA with scores that correlated with nurse judgement [r (184) =0.86, p< .0001]. Patients needed time and support to perform testing without assistance for optimal accuracy and benefit. Patients reported CMET was useful (88%) and easy (62%) and identified barriers that limit walking while hospitalized. Study limited by research at a single site. This study represents the initial validation, confirming reliability and benefits of the CMET, a skill-based tool to evaluate mobility status. Providing time and encouragement to perform CMET helps nurses and patients to identify deficits and tailor care to overcome mobility barriers.

Prevalence of multidrug-resistant Gram-negative bacteria causing pyogenic infections at a tertiary care hospital in Haryana

Abstract Background: The growing occurrence of antibiotic-resistant bacteria, especially those resistant to multiple drugs found in pyogenic infections, presents considerable challenges in effectively managing and curing these infections. Objective: This current research aimed to determine the prevalence of Gram-negative bacteria with multidrug resistance in cases of pyogenic infections treated at a tertiary care hospital located in Haryana, India. Materials and Methods: An observational cross-sectional investigation was conducted over 8 months, from June 2022 to January 2023, at a tertiary care hospital located in Haryana, India. Throughout the study, 376 samples of pus and wound swabs were gathered from patients visiting the outpatient and inpatient departments. Subsequently, specimens that exhibited noteworthy aerobic bacterial growth were identified following established bacterial testing procedures, and their antibiotic susceptibility profiles were determined using the Kirby-Bauer disc diffusion method. Results: Out of the total 376 collected pus and wound swab specimens (n = 376), significant aerobic bacterial growth was observed in 116 cases (30.9%), with 113 instances (97.4%) showing monomicrobial growth and the remaining three cases (2.6%) exhibiting polymicrobial growth. Consequently, a sum of 119 bacterial isolates was obtained, with 70 (58.8%) being Gram-negative bacilli (GNB) and 49 (41.2%) being Gram-positive cocci. Among the GNB isolates, 37 (52.9%) were identified as Gram-negative fermenters (belonging to the Enterobacteriaceae family), while the remainder were categorized as Gram-negative non-fermenters. The prevalent isolate was Pseudomonas aeruginosa, accounting for 42.9% of the cases, Escherichia coli at 25.7%, and Enterobacter species at 7.1%. Of these isolates, 31 (44.3%) were multidrug-resistant, 24 were Gram-negative fermenters, and seven were Gram-negative non-fermenters. Approximately three-quarters of the Enterobacteriaceae isolates showed potential for producing extended-spectrum β-lactamases, whereas a quarter exhibited potential for producing carbapenemases. Similarly, a quarter of the Gram-negative non-fermenters were identified as potential carbapenemase producers. Conclusion: The present study underscores the prevalence of multidrug-resistant strains within the pathogens, particularly among Enterobacteriaceae isolates responsible for pyogenic infections. Additionally, these findings will play a pivotal role in shaping a community-specific antimicrobial stewardship initiative, which stands as one of the most essential strategies for addressing the challenge of antimicrobial resistance.

Socialization and Production of Ecoenzyme Fluid in Tanjung Kasau Plantation Village, Batubara District

Ecoenzyme is a solution of complex organic substances produced by the fermentation process of organic waste, water, and molasses. So that organic waste that has been disposed of and is no longer used can be utilized as an environmentally friendly product. This eco-enzyme solution is dark brown in color and has a strong sour aroma. This socialization and demonstration focuses on making Ecoenzyme solutions from organic waste grapefruit, pumpkin, kale, chicory and papaya from household waste which aims to educate the public, especially housewives in Tanjung Kasau Plantation Village to know the procedure for making Ecoenzyme and using waste organic. Using an experimental method, an Ecoenzyme solution was made with 1 part molasses, 3 parts fruits and vegetables, and 10 parts clean water and then fermented for 3 months to make an Ecoenzyme solution. For the first 1 month the test was carried out Periodically, samples are taken every 2 days and evaluated for find out the evaluation parameters including organoleptic, pH and appropriate viscosity established test procedures. The results of this study showed that a good Ecoenzyme had a dark brown color, a fresh sour aroma typical of spicy and get a stable pH with a pH of 4.0 showing a high eco-enzyme produced is acidic which has benefits such as radiation protection, clearing drains, floor cleaners, organic disinfectants etc.

Design for Test With Unreliable Memories by Restoring the Beauty of Randomness

In nm-technologies and especially under voltage scaling, memories require costly protection to provide 100% reliable operation. However, many recent studies show that application fault-tolerance can provide acceptable average-quality even with unreliable memories. Unfortunately, this popular approximate computing concept is often justified with random fault injection simulations which are deceiving since faults caused by variability in the manufacturing process are different (in fact often deterministic) for each die. However, established test procedures can not distinguish dies delivering poor quality from those with acceptable quality. To solve this fundamental issue, we describe a new design-for-test strategy that allows to provide reliable quality-guarantees for each die in the presence of reliability issues in memories with a straightforward standard test procedure.

The ‘miniature silo’ test: A simple experimental setup to estimate the effective friction coefficient between the granular solid and a horizontally-corrugated cylindrical metal silo wall

Corrugated walls are widely employed in the construction of metal silos. Despite the long history of testing to establish bulk material parameters for silo design, there does not appear to be an established test procedure to directly determine the effective friction coefficient for a corrugated wall other than an adaptation of a classical direct shear test. EN 1991-4: 2006 prescribes a simple weighted average formula for this coefficient based on the internal friction angle of the granular solid and a ‘flat’ wall friction coefficient. This paper describes a set of miniature-scale silo tests performed at the University of Bologna intended to establish a simple but useful procedure to directly estimate an average global friction coefficient between the granular solid and a corrugated silo wall. These ‘miniature silo’ tests are simple enough to be performed in any civil engineering laboratory with standard equipment. • Particle-wall friction coefficient is fundamental for structural design of silos. • No tests are available to measure the effective friction for a corrugated wall. • A novel straightforward experimental test is proposed to fill this gap. • The miniature-silo test can be built using basic tools easy to be found in any lab. • The obtained results are in accordance with EN-1991-4 average formula predictions.

Olympic Rowing – Maximum Capacity over 2000 Meters

Olympic rowing in its current form is a high-intensity boat race covering a distance of 2000 m with fastest race times ranging ~5.5-7.5 min, depending on boat class, sex, and environmental factors. To realize such race times, rowers need strength and endurance, which is physiologically evident in an oxidative Adaption of the skeletal muscles, a high aerobic capacity, and the ability to contribute and sustain a relatively high percentage of anaerobic energy for several minutes. Anthropometrically, male and female rowers are characterized by relatively large body measurements. Biomechanics & Physiology: The sitting position of the rower, the involvement of a large muscle mass and the structure of the rowing cycle, consisting of drive and recovery phase where the rower slides back and forth on a sliding seat, affect the cardiovascular and the respiratory system in a unique manner. In Addition to these physiological and anthropometric characteristics, this brief review outlines the extreme metabolic implications of the sport during racing and training and mentions rarely-discussed topics such as established testing procedures, summarizes data on training intensity distribution in elite rowing and includes a short section on heat stress during training and racing in hot and humid conditions expected for the Olympic Games 2021 in Tokyo.

Recording Obligatory Cortical Auditory Evoked Potentials in Infants: Quantitative Information on Feasibility and Parent Acceptability.

With the advent of newborn hearing screening and early intervention, there is a growing interest in using supra-threshold obligatory cortical auditory evoked potentials (CAEPs) to complement established pediatric clinical test procedures. The aim of this study was to assess the feasibility, and parent acceptability, of recording infant CAEPs. Typically developing infants (n = 104) who had passed newborn hearing screening and whose parents expressed no hearing concerns were recruited. Testing was not possible in 6 infants, leaving 98, age range 5 to 39 weeks (mean age = 21.9, SD = 9.4). Three short duration speech-like stimuli (/m/, /g/, /t/) were presented at 65 dB SPL via a loudspeaker at 0° azimuth. Three criteria were used to assess clinical feasibility: (i) median test duration <30 min, (ii) >90% completion rate in a single test session, and (iii) >90% response detection for each stimulus. We also recorded response amplitude, latency, and CAEP signal to noise ratio. Response amplitudes and residual noise levels were compared for Fpz (n = 56) and Cz (n = 42) noninverting electrode locations. Parental acceptability was based on an 8-item questionnaire (7-point scale, 1 being best). In addition, we explored the patient experience in semistructured telephone interviews with seven families. The median time taken to complete 2 runs for 3 stimuli, including preparation, was 27 min (range 17 to 59 min). Of the 104 infants, 98 (94%) were in an appropriate behavioral state for testing. A further 7 became restless during testing and their results were classified as "inconclusive." In the remaining 91 infants, CAEPs were detected in every case with normal bilateral tympanograms. Detection of CAEPs in response to /m/, /g/, and /t/ in these individuals was 86%, 100%, and 92%, respectively. Residual noise levels and CAEP amplitudes were higher for Cz electrode recordings. Mean scores on the acceptability questionnaire ranged from 1.1 to 2.6. Analysis of interviews indicated that parents found CAEP testing to be a positive experience and recognized the benefit of having an assessment procedure that uses conversational level speech stimuli. Test duration, completion rates, and response detection rates met (or were close to) our feasibility targets, and parent acceptability was high. CAEPs have the potential to supplement existing practice in 3- to 9-month olds.

Nonparametric tests for stratified additive hazards model based on current status data

Stratified regression models are commonly employed when study subjects may come from possibly different strata such as different medical centers, and for the situation, one common question of interest is to test the existence of the stratum effect. To address this, there exists some literature on the testing of the stratum effects under the framework of the proportional hazards model when one observes right-censored data or interval-censored data. In this paper, we consider the situation under the additive hazards model when one faces current status data, for which there does not seem to exist an established test procedure. The asymptotic distributions of the proposed test procedure are provided. Also a simulation study is performed to evaluate the performance of the proposed method and indicates that it works well for practical situations. The approach is applied to a set of real current status data from a tumorigenicity study.

Comparison of a rapid detection fluorescence-based assay targeting tuberculocidal efficacy with EN 14348 and EN 14563

A rapid test system using fluorescent Mycobacterium terrae to evaluate the tuberculocidal efficacy of disinfectants has recently been published. Results were obtained in a significantly shorter time than was previously possible. To compare the European Standard test system with the fluorescence assay and to validate the rapid test system, including particularly the quantitative suspension test. Quantitative suspension tests and quantitative carrier tests were carried out according to EN 14348 and EN 14563, respectively. Quantitative carrier tests and subsequent green fluorescent protein (GFP)-based determination of germicidal efficacy were carried out as described previously. A peracetic acid-based formulation was used as a test germicide. Testing of the germicide in the quantitative suspension test EN 14348 and in the quantitative carrier test EN 14563 revealed tuberculocidal efficacy at a concentration of 1% after 15 min contact time. Accordingly, data obtained from the fluorescence assay demonstrated that a germicide concentration of 1% was effective after 15 min, indicating no live mycobacteria following this treatment. Thus, identical in-use parameters for tuberculocidal efficacy were obtained either by applying the quantitative suspension and quantitative carrier tests EN 14348 and EN 14563 or by using the GFP-based rapid test system. The GFP-based rapid test system compares well with the established European Standard test procedure including both phase 2, step 1 and phase 2, step 2 tests and provides a rapid and sensitive tool for testing germicides for relevant in-use concentrations and contact times.

Reliability and reliability investigation of wide-bandgap power devices

Established reliability test procedures from Si can widely be applied to SiC, however there are some differences and special challenges. A new test procedure for the gate oxide reliability is suggested, it leads to evaluable results within a reasonable time. Temperature-sensitive electrical parameters (TSEPs), which are necessary for power cycling tests, are investigated. For the SiC MOSFET and the GaN GIT, possible TSEPs are compared and applied to power cycling tests. GaN-based devices have further issues regarding reliability, like charge trapping, dynamic Ron, and degradation effects. The test matrix from Si is not sufficient to cover the reliability requirements for GaN.

Testing and modeling the behavior of sandwich lightweight panels against wind and seismic loads

The behavior of non-structural sandwich lightweight panels against wind and seismic loadings is not well understood. Such panels are typically composed of two calcium-silicate board (CSB) wythes separated by a core infill made of expanded polystyrene lightweight concrete (LWC). This paper provides understanding regarding the mechanisms of panel connectivity by tongue-and-groove, including transfer of forces through steel dowels to the existing structure. Series of LWC mixtures having 470 to 975 kg/m3 density were tested using suitably established testing procedures to determine the flexural strength, core shear strength, interfacial bond between LWC and CSB, and pullout forces transmitted through the steel dowels. Special emphasis is placed on modeling the effect of wind and seismic loads on a 3.6 × 3 m2 partition wall constructed using LWC sandwich panels. The highest stresses and deformations generated from the model are compared to those determined experimentally, which allowed establishing different charts that can predict the safety factors as a function of LWC density and type/magnitude of the lateral loading applied.

Biomarker-Stratified Phase III Clinical Trials: Enhancement with a Subgroup-Focused Sequential Design.

Among various design approaches to phase III clinical trials with a predictive biomarker, the marker-stratified all-comers design is advantageous because it allows for establishing the utility of both treatment and biomarker, but it is often criticized for requiring large sample sizes, as the design includes both marker-positive and marker-negative patients. In this article, we propose a simple but flexible subgroup-focused design for marker-stratified trials that allow both sequential assessment across marker-defined subgroups and adaptive subgroup selection while retaining an assessment using the entire patient cohort at the final analysis stage, possibly using established marker-based multiple testing procedures. Numerical evaluations indicate that the proposed marker-stratified design has a robustness property in preserving statistical power for detecting various profiles of treatment effects across the subgroups while effectively reducing the number of randomized patients in the marker-negative subgroup with presumably limited treatment efficacy. In contrast, the traditional all-comers and sequential enrichment designs could suffer from low statistical power for some possible profiles of treatment effects. The latter also needs long study durations and a large number of marker-screened patients. We also provide an application to SWOG S0819, a trial to assess the role of cetuximab in treating non-small cell lung cancers. These evaluations indicate that the proposed subgroup-focused approach can enhance the efficiency of the marker-stratified design for definitive evaluation of treatment and biomarker in phase III clinical trials. Clin Cancer Res; 24(5); 994-1001. ©2017 AACR.

Influence of the deep hole drilling process and sulphur content on the fatigue strength of AISI 4140 steel components

When using quenched and tempered steels in the automotive industry or other industrial applications the fatigue behavior is of elementary importance. The surface and subsurface integrity of machined parts is known as one key factor related to the fatigue strength of components and is strongly influenced by the machining process. Especially for the deep hole single lip drilling, a large part of the cutting force is transferred to the bore wall and the surface and subsurface zone are influenced by the interaction between the tool and the workpiece material.In this study, the approach of inserting residual stresses into the bore wall and influencing the microstructure of the bores subsurface in a way, that the components can withstand a higher mechanical and dynamic load, is investigated in detail. In a close cooperation between the authors the parameters of the single-lip drilling process and the workpiece material are correlated with the produced surface quality and subsurface microstructure as well as the resulting fatigue strength of the components. For the comparative characterization of the fatigue behavior, established test procedures of destructive material testing in combination with new non-destructive test methods, such as the Barkhausen noise analysis, are applied and developed further. The results of the fatigue tests in correlation with the results of the Barkhausen noise analysis are used to design a model for predicting the fatigue strength of drilled components.

Development of a Composite Friction Material with Excellent Fade Resistance by Employing Oversized Ceramic Particles

Non-asbestos organic friction materials have historically been developed through a series of trial-and-error experimental procedure. But in this work, the friction theory was used to design and prepare a new composite friction material with excellent fade resistance. Oversized (3.0 ± 0.5 mm) SiO2-based particles with the great thermal stability and large contact area against the disc were used to reinforce the resin matrix. The effectiveness of the oversized particles relative to particles of other sizes was evaluated using an established test procedure. The results showed that the oversized particles improve the fade resistance and wear resistance of materials, but not followed with excessive disc wear.

Simulation of the scenario of the biaxial wheel fatigue test

This paper presents a new approach to the virtualization of the scenario of the biaxial wheel fatigue test. This test is the state-of-art and the standard requirement for the validation of vehicle wheels. During this test, tire and wheel specimens run inside an inner drum while standardized vertical and horizontal loads are applied. Thus, the scenario of this test can be modeled in three levels: the multibody dynamics of the test facility, the wheel/tire/inner drum contact, and the analysis of the flexible wheel. In the proposed virtualization, the multibody dynamics of the test facility was implemented in MSC.ADAMS. The wheel/tire/inner drum contact was simulated by means of CDTire; as it works parallel to MSC.ADAMS, one single co-simulation could perform the tire dynamics and the test facility dynamics. Finally, the wheel strains were calculated by an ABAQUS simulation, which received the tire/wheel load data from the simulation in MSC.ADAMS and CDTire. A physical test facility and a physical wheel specimen were instrumented, allowing the comparison between acquired and simulated data. The use of this specialized software is a novelty in the virtualization of the scenario of this test; furthermore a high detailed simulation is required for the further development of such already well established test procedure.

Development of durability test procedure of vibration-based energy harvester in railway vehicle

This study aims to develop a durability test procedure for vibration-based energy harvesters in the frequency domain. First, we investigated the vibration environment of a structure on which an energy harvester may be installed and determined the level and frequency range of the power spectral density (PSD) exerted on the energy harvester. Consequently, we developed a test procedure, which is composed of the PSD and sinusoidal sweep loads. The test system was built using a vibration exciter, data acquisition unit, and LabView-based control software. Using the developed test system, durability performance tests for two types of energy harvesters were performed according to the established test procedure.

Efficiency Measurements in Induction Motors: Comparison of Standards

Recently, given the need to reduce the emission of greenhouse effect gases and limiting the steady increase in energy demand, were have proposed new standards of efficiency levels of electric motors. From them have been defined efficiency categories, which determine the limits for so called Standard Efficiency Motors, High Efficiency, Efficiency Premium, etc. Most countries, therefore, have established legal restrictions on the use of motors with low efficiency. A small error in the motor efficiency measurement could lead to an incorrect categorization. In this sense recently have been revised standards that establish testing procedures. Each one, in turn, provides different alternatives more or less accurate to estimate the motor efficiency based on the tools that are included (dynamometer torque sensor, windings temperature measurement, etc.). In this paper a comparison of some of the most commonly used standards for the motor efficiency measurement is presented. The comparison is made in reference to the so-called direct method, where the input and output power of a motor is directly measured with a strict control of ambient (laboratory), engine temperature and feeding conditions. The comparisons allow conclusions about the probable errors in the application of each standard.

A TECHNICAL REVIEW OF PRODUCER GAS AS AN ALTERNATIVE FUEL FOR INTERNAL COMBUSTION ENGINE

This paper describes the current state of available gasification technology for utilizing producer gas for I.C engine application & different ways to optimize the performance. Producer gas is promising alternative fuel to meet energy demand in many countries which is defined as gas generation from solid waste through thermo chemical conversion route (also termed as gasification) can be used for fuelling a compression ignition (CI) engine in duel fuel mode or a spark ignition (SI) engine in the gas alone mode. This technology is also environmentally benign and holds large promise for the future. This paper summarizes the work conducted using biomass derived producer gas in reciprocating internal combustion engines. Survey in the field of producer gas based engines reveals modest research work have been carried out since the inception of biomass/ charcoal gasification systems. Producer gas contains a large fraction of inert (> 50%) and with laminar burning velocity being high (due to presence of H2), smooth operation at higher Compression ratio does not seem impossible. These aspects are very vital in establishing the fact that close to comparable power (with a lesser extent of de-rating 15-20%) with producer gas by operating in engine at higher compression ratio. This could be attributed to two reasons, namely non- availability of standard gasification system that could generate consistent quality producer gas and the other relating to misconceptions about producer gas (related to compression ratio limitation due to knock tendency and de-rating). The knock tendency can be expected to be better on account of large fraction of inert gas as compared to natural gas. However, there has not been any research on octane rating test conducted on producer gas fuel and moreover it is not clear if any established test procedure exists for producer gas like the methane number test for natural gas and biogas. De-rating could be due to reduction in the mixture energy density and the product-toreactant mole ratio. If one were to summarize earlier studies, it becomes evident that no systematic investigation has been attempted so far in identifying if limitation of knock exists with producer gas operation at compression ratio comparable with the diesel engine operation.