Computer-aided fault detection for sucker rod pump is a crucial technology to monitor wells in the oil production. According to the detection results, engineers could take corresponding measures to ...ensure wells operating in a safe and productive state. Generally, the conventional approaches to address this problem are mainly based on dynamometer cards, but these methods have obvious defects in security risks and high maintenance cost in the application. Noteworthy, the motor is the energy resource of sucker rod pump and the change of motor’s power could reflect the variation of the working states. Therefore, in this paper, a novel method based on motor power for detecting the working state of the sucker rod pump is proposed. In this method, a set of the labeled motor power curve is essential. To obtain this vital information resource, the motor power curves are labeled by transforming them into dynamometer cards, which fully consider many crucial factors in this process. Moreover, to obtain useful information from motor power data, eight novel features are defined by analyzing the mechanism of motor work and the data distribution of the curve. Subsequently, the hidden Markov model (HMM), a probabilistic model with the double stochastic process, is employed to map the relationships between motor power data and working states. At last, the proposed method is verified experimentally using an oil dataset collected from oil field including six different working states, and then this technique is compared with some other methods. In the comparison, the proposed method gives 91.7% correct diagnosis that is higher than the 72.9% of SVM and the 62.5% of ANN. The experimental results show that the performance using the method proposed in this paper is satisfactory.
This paper investigates off-the shelf performance traction machine, a yokeless and segmented armature (YASA) axial flux surface permanent magnet machine, model P400HC from YASA Motors. A series of ...manual measurements and automated dynamometer tests were performed at various conditions. From these tests parameters are determined including friction and windage torque, phase resistance, permanent magnet flux linkage, and inductance. The efficiency, phase current, phase voltage, and power factor of the machine was measured over a wide torque, speed, and dc bus voltage range up to around the maximum ratings given by the manufacturer. A range of d-q current values were tested, showing that the machine is slightly salient since maximum torque is achieved when including a small amount of d-axis current. A Chevrolet Bolt electric vehicle (EV) was modeled with the YASA Motors machine and the stock Bolt EV machine. Over four different vehicle drive cycles, the YASA Motors machine was shown to be considerably more lossy than the Bolt EV machine, thereby achieving 4% to 6% less range. The higher loss of the YASA Motors machine likely has several causes, including higher phase resistance, significant friction, windage, and no-load iron losses, and the fact that Bolt EV machine was heavily optimized for an EV application while the YASA Motors machine was optimized to be a highly power dense more general-purpose machine.
Abstract
This study aimed to investigate the relationship between Leg Dynamometer (LD) with squat and deadlift one repetition maximum (1RM) test scores. Participant of this study involved 50 male ...university athletes who were recreationally active (aged between 21-25 years old). Participants performed LD and one repetition maximum for squat and deadlift test. The score of LD were tested for relationship with the 1RM squat and deadlift. Pearson correlation were conducted to test the relationship. Results showed that there was a significant correlation at high level (r = 0.88, p = 0.000, p <0.001) between the LD test score and the squat while a very high correlation was obtained between the LD test score and the deadlift (r = 0.98, p = 0.000, p <0.001). As the conclusion, LD test that is simple and easy to be conducted produce similar result as the squat and deadlift 1RM test and can be used as a simple assessment of muscular strength among university athletes.
Hand grip strength has been widely used as a lead measure in geriatric conditions such as frailty. However, diversity in assessment protocols and methodologies creates uncertainty in the comparison ...of outcome measurements. The aim of this study was to review the literature relating to the measurement of hand grip strength in older adults, in order to develop further consensus in relation to the use of existing protocols in clinical and community settings, with an emphasis on practicality and suitability for frail persons.
Five electronic English databases were searched using keywords such as ‘hand grip strength’, ‘clinimetric assessment’, and their synonyms. Age-related trends in adults aged ≥65 years were assessed, and comparisons were made of the following variables: dynamometer model and handle setting, hand positioning, warm-up trials, grip duration, number of repeated tests, rest periods, laterality of tested hand, and whether encouragement was given to the subjects.
Thirty-four research papers met the inclusion criteria and were included. A Jamar hand dynamometer was most frequently used. Variations were found in the positioning of the subject and in the duration of the rest period, which ranged from 10 to 20 s to 1 min. Grip strength was typically measured three times in the dominant hand, with the strongest grip being recorded and no encouragement being provided during assessment.
Based on the scoping review, we propose a detailed and standardised protocol that is suitable for the assessment of hand grip strength in frail older adults.
•Study shows higher muscle activation in non-dominant limbs during movement phases.•Isokinetic and isotonic modes differ significantly in muscle engagement.•Lower force and power in standing up than ...sitting down in isokinetic mode.•Significant statistical differences highlight variability in muscle performance.
to explore lower limb muscle activity concerning limb dominance, as well as variations in force and power during the standing up and sitting down phases of the instrumented sit-to-stand-to-sit test in sedentary individuals, across isokinetic and isotonic modalities.
33 sedentary individuals underwent testing using a functional electromechanical dynamometer in both isokinetic and isotonic modes, accompanied by surface electromyography.
In the isokinetic mode, the non-dominant gastrocnemius medialis and vastus medialis exhibited significantly (p < 0.05) higher muscle activity values during the standing up and sitting down phase compared to dominant counterparts. In the isotonic mode standing up phase, significant differences in muscle activity were noted for non-dominant gastrocnemius medialis, vastus medialis, and biceps femoris compared to their dominant counterparts. The sitting down phase in isotonic mode showed higher muscle activity for non-dominant vastus medialis compared to dominant vastus medialis. Regard to performance outcomes, significantly lower (p < 0.0001) values were observed for standing up (12.7 ± 5.1 N/kg) compared to sitting down (15.9 ± 6.1 N/kg) peak force, as well as for standing up (18.7 ± 7.8 W/kg) compared to sitting down (25.9 ± 9.7 W/kg) peak power in isokinetic mode. In isotonic mode, lower values were found for sitting down (6.5 (6.3–7.1) N/kg) compared to standing up (7.8 (7.3–8.9) N/kg) peak force and for sitting down (18.5 (13.2–21.7) W/kg) compared to standing up (33.7 (22.8–41.6) W/kg) peak power.
Limb dominance influences lower-limb muscle activity during the instrumented sit-to-stand-to-sit test, and the choice of testing mode (isokinetic or isotonic) affects muscle engagement and performance outcomes.
PURPOSE OF REVIEWGrip strength measured by dynamometry is well established as an indicator of muscle status, particularly among older adults. This review was undertaken to provide a synopsis of ...recent literature addressing the clinical and prognostic value of hand-grip dynamometry.
RECENT FINDINGSNumerous large-scale normative grip strength projects have been published lately. Other recent studies have reinforced the concurrent relationship of grip strength with measures of nutritional status or muscle mass and measures of function and health status. Studies published in the past few years have confirmed the value of grip strength as a predictor of mortality, hospital length of stay, and physical functioning.
SUMMARYAs a whole, the recent literature supports the use of hand-grip dynamometry as a fundamental element of the physical examination of patients, particularly if they are older adults.
Abstract
Background
The Jamar hydraulic dynamometer is a widely recognized tool for measuring grip strength. Nevertheless, the devices used most often in Asian countries are spring-type dynamometers, ...represented by the CAMRY dynamometer or Smedley dynamometer. We aimed to evaluate the reliability and validity of the CAMRY dynamometer compared with the Jamar dynamometer.
Methods
This was a cross-sectional study using a random crossover design in the grip strength test with two dynamometers. A total of 1064 healthy community-dwelling older adults aged 50–90 years old, which included 686 minorities and 378 Han Chinese, were recruited into the study from July to September 2021. We assessed the reliability and validity of the CAMRY EH101 dynamometer, and the Jamar dynamometer was regarded as the reference device. The order of testing with two dynamometers was randomized in a 1:1 ratio, with a 10-min gap between the two devices. Intraclass correlation coefficients (ICCs) and Bland–Altman analysis were calculated to assess reliability and validity between the two devices.
Results
The average handgrip strength (HGS) values at six times by the Jamar and CAMRY devices were 25.0 ± 7.9 kg and 24.6 ± 7.5 kg, respectively. The ICC values between the two devices were 0.815–0.854, and the systematic bias underestimated by the CAMRY dynamometer was 0.5 kg in men and 0.6 kg in women. We carried out a linear regression equation by sex, and their relationship was found as follows: male HGS (kg)
Jamar
= 8.001 + 0.765 × HGS (kg)
CAMRY
; female HGS (kg)
Jamar
= 3.681 + 0.840 × HGS (kg)
CAMRY
.
Conclusions
The CAMRY EH101 dynamometer provides excellent reliability and validity. This device can serve as a reliable, inexpensive, and practical device to assess grip strength in geriatric clinical practice.
Clinical trial registration
Chinese Clinical Trial Registry:
ChiCTR2100046367
; Date of clinical trial reistration: 15/05/2021.
Purpose
In order to provide science-based guidelines for injury prevention or return to play, regular measurement of isometric and eccentric internal (IR) and external (ER) rotator strength is ...warranted in overhead athletes. However, up to date, no normative database exists regarding these values, when measured with a hand-held dynamometer. Therefore, the purpose of the study was to provide a normative database on isometric and eccentric rotator cuff (RC) strength values in a sample of overhead athletes, and to discuss gender, age and sports differences.
Methods
A HHD was used to measure RC strength in 201 overhead athletes between 18 and 50 years old from three different sports disciplines: tennis, volleyball and handball. Isometric as well as eccentric strength was measured in different shoulder positions. Outcome variables of interest were isometric ER and IR strength, eccentric ER strength, and intermuscular strength ratios ER/IR.
Results
Our results show significant side, gender and sports discipline differences in the isometric and eccentric RC strength. However, when normalized to body weight, gender differences often are absent. In general, strength differences are in favour of the dominant side, the male athletes and handball. Intermuscular ER/IR ratios showed gender, sports, and side differences.
Conclusion
This normative database is necessary to help the clinician in the evaluation of RC strength in healthy and injured overhead athletes. In view of the preventive screening and return-to-play decisions in overhead athletes, normalization to body weight and calculating intermuscular ratios are key points in this evaluation.
Level of evidence
Diagnostic study, Level III.
Vehicle emissions are affected by factors such as vehicle type, fuel quality, and engine repair. Therefore, mobile source profiles should be established based on a characteristic fleet for a specific ...region. This study characterised the chemical composition of PM2.5 emitted from motor vehicles that are commonly used in Xi'an through dynamometer tests. The tested fleet included light duty diesel vehicles (LDDVs; eight sample sets), heavy duty diesel vehicles (HDDVs; six sample sets), light duty gasoline vehicles (LDGVs; eight sample sets), one natural gas vehicle (NGV; four sample sets) and one methanol vehicle (MV; two sample sets). Similarities and differences among the source profiles were compared and evaluated. Overall, carbon species (13.14–59.11%) were the major components of PM2.5 for each type of vehicle, and the content of organic carbon (OC) was generally higher than that of elemental carbon (EC). Moreover, NO3− (18.577–220.062 mg·g−1) was the dominant water-soluble ion and the Ca2+ (2.429–17.209 mg·g−1) and Na+ (1.966–20.798 mg·g−1) contents in PM2.5 were high. In terms of elements, the PM2.5 emitted from various types of vehicles consisted of abundant Al (2.183–94.949 mg·g−1), Fe (0.567–12.297 mg·g−1), and Zn (0.659–5.195 mg·g−11). In addition, the PM2.5 profiles were significantly affected by fuel type. In general, emissions from the LDGVs and NGV exhibited higher contents of OC (477.0–479.1 mg·g−1). The greatest fractions of water-soluble ions (32.94%) and total elements (11.74%) were observed in emissions from the NGV and MV, respectively. For the same type of vehicle, the OC/EC ratio was possibly dependent on the emission standards. The PM2.5 emitted from the LDDVs with stricter emission standards exhibited higher OC/EC ratios, whereas the OC/EC ratios displayed a decreasing trend for the LDGVs under more stringent emission standards.
Display omitted
•PM2.5 profiles of conventional and alternative fuel vehicles were characterised.•Gasoline and natural gas vehicles emitted higher contents of OC.•The highest fraction of water-soluble ions was observed from the NGV.•The highest percentage of elements was observed from the MV.•The OC/EC ratio was impacted by the emission standards for the same type of vehicle.
Europe's regulation of passenger car emissions has been proven to have failed when it comes to nitrogen oxide emissions (NOx) by diesel engines. Due to historical decisions favouring diesel ...technology, Europe has become a diesel island with no equal worldwide. As a result, virtually every European citizen breathes in air which is deemed harmful to human health. Real driving emissions (RDE) testing by means of portable emissions measurement systems (PEMS) can potentially eliminate the discrepancy between lab and road tests, and will complement the dynamometer type-approval procedure from September 2017 onwards. Despite the significant potential of PEMS testing, the emission assessment has been watered down through politics to provide the automotive manufacturers with additional lead-time. In this way, the lab to road gap is not eliminated but only decreased. This means that diesel cars will continue to over-emit NOx until the 2020s at earliest. This has consequences for effectively bringing down local air quality issues, especially in low emission zones (LEZ).
This paper presents a review of the European emission regulation history up to date and makes a comparison with the approach in the other important car markets globally. One can conclude that a substantial update of the European regulatory framework concerning automotive emissions is required, while ambitious post-2021 targets should be set if Europe does not want its automotive industry to lose its competitive position in the global market. In addition, an equilibrium should be sought for between sustainable personal transport in the form of zero-emission vehicles (ZEV), and a sustainable economic climate for the automotive industry. The former is needed if LEZs are to effectively bring down pollutant levels in cities.
•Euro 5 & 6 failed for diesel NOx.•RDE testing will not bridge the gap between laboratory and road tests.•LEZs won’t generate the desired improvements in the local air quality in cities.
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