Measuring the effects of structural turnout suits on firefighter range of motion and comfort

Abstract

Range of motion (ROM) can be restricted by wearing stiff and bulky clothing. This is particularly true of firefighter suits that are constructed using fabric layers to provide thermal protection from fire. This study developed an evaluation technique to quantify the loss of mobility associated with wearing firefighters’ protective suits that were deliberately selected to represent similar ergonomic design features. The ROM of 10 firefighters was measured using electro-goniometers attached to their bodies while they wore uniforms and a reference outfit, and performed specific movements. The most restrictive uniform is the Bulky suit that contained additional layers of materials in sleeves and on the knees. The Traditional Suit was more ROM restrictive than Ergonomic. The subjective evaluation of suits supported the objective assessments provided by the electro-goniometers. A 3-D body scanning technique was employed to establish a correlation between the bulkiness of firefighter outfits and subject ROM.

Practitioner Summary: This study presents a methodology for measurements of range of motion (ROM) in firefighters wearing personal protective equipment (PPE). Even small differences in designs of PPE may impact firefighters’ ROM, which can be detected by electro-goniometers providing measurements if they are attached along the joint to measure limb angular movement.     

Investigation of the effects of perturbation forces to buckling in internally pressurized torispherical pressure vessel heads

The object of this paper is to investigate the effects of perturbation forces to buckling in pressure vessel heads. The pressure vessel heads in concern are confined to torispherical geometry with thin walls. Perturbation forces can alter not only the critical load for buckling but the buckled shape as well. In this paper in addition to previously used perturbation model, three more different perturbation force configurations are applied to the knuckle of the vessel. Internally pressurized three-dimensional torispherical pressure vessel head model that is previously used in literature is constructed and finite element program ANSYS Workbench is used for the solutions. First of all eigenvalue solutions are performed for each model. Then nonlinear instability solutions are conducted to obtain more realistic instability pressure values. For the nonlinear analyses not only large deformation static analyses but also large deformation transient analyses are conducted. For nonlinear analyses, perfectly plastic material model is used. It is concluded that instability pressures obtained by transient analyses are closer to plastic pressure values by PWC and ASME TES criteria and perturbation models increase instability pressure and equivalent plastic strain values.     

Tau approximate solution of fractional partial differential equations

In this study, we improve the algebraic formulation of the fractional partial differential equations (FPDEs) by using the matrix-vector multiplication representation of the problem. This representation allows us to investigate an operational approach of the Tau method for the numerical solution of FPDEs. We introduce a converter matrix for the construction of converted Chebyshev and Legendre polynomials which is applied in the operational approach of the Tau method. We present the advantages of using the method and compare it with several other methods. Some experiments are applied to solve FPDEs including linear and nonlinear terms. By comparing the numerical results obtained from the other methods, we demonstrate the high accuracy and efficiency of the proposed method.     

偏联系数的计算与应用研究

偏联系数是联系数的一种伴随函数,其计算过程反映出联系数的联系分量在各个微观层次上的“矛盾运动”,计算结果指示出这种“矛盾运动”的阶段性结果,是“系统宏观状态与微观趋势多层分析法”的主要数学工具。本文系统阐述常用的二元至五元联系数的偏联系数算法和若干新思路,并从智能技术创新和信息能开发利用等角度指出偏联系数算法是一种新的智能算法。     

Ranges of dynamic motion of the wrist in healthy young and middle-aged men

The difference in the range of dynamic motion of the wrist between young and middle-aged men was studied. To analyse wrist function easily, a new quantitative evaluation technique for wrist circumduction using a biaxial flexible electrogoniometer was introduced. A phase plane was made from two-channel signals of the electrogoniometer, and the ‘ROM (range of motion) Index’ for wrist circumduction was defined. Twelve healthy young men (age 19-31 years) and twelve healthy middle-aged men (age 45-63 years) were studied. Under forearm fixed conditions, there was no difference of the ROM Index between the two age groups. A significant decrease of the ROM Index in the middle-aged group was found in the non-dominant wrists without forearm fixation. The four quadrantal analysis of wrist circumduction clarified that this difference appeared especially in the radiodorsal direction. These results suggest that in the middle-aged men, the motor function involving the radiocarpal and midcarpal joints does not decrease, but that for the proximal and distal radioulnar joints in the non-dominant side drops.     

The interacting effects of forearm rotation and exertion direction on male and female wrist strength

The accurate estimation of wrist strength is an important component of ergonomics task evaluation, as a vast majority of occupational tasks involve use of the hands to generate forces and moments. The purpose of this study was to examine the interacting effects of forearm rotation (pronation/supination) and wrist exertion direction on strength at the wrist joint in males and females. A total of 24 male and female participants performed maximum isometric wrist exertions while maintaining a non-deviated wrist posture (no flexion/extension or radial/ulnar deviation) and an open hand. Maximum wrist moments were obtained in combinations of three forearm rotations (90° pronation, neutral, 90° supination) and four exertion directions (flexion, extension, radial and ulnar deviation). A greater effect of forearm rotation was observed for males, as strength in the neutral forearm posture was significantly different than pronated and supinated postures in 5 of 8 comparisons. For females, both wrist flexion and extension strengths were higher in neutral, compared to supinated forearm postures. The findings of this study suggest that wrist strength does depend on forearm rotation, and this interaction between axes needs to be accounted for in future strength capability estimates.Relevance to industryThis study shows that wrist strength estimates, currently used by ergonomics software packages in industry, can be improved to more accurately reflect the actual wrist strength capabilities of workers during hand-intensive tasks.     

Supply chain information integration and its impact on the operational performance of manufacturing firms in Malaysia

PurposeThe purpose of this paper is to investigate the impact of Supply Chain Information Integration (SCII) on the Operational Performance of manufacturing firms in Malaysia considering the role of information leakage.Design/methodology/approachTo test the model developed, we conducted an online questionnaire survey with Malaysian manufacturing companies drawn from the Federation of Malaysian Manufacturers directory of 2018. Out of the 400 questionnaires sent out to the manufacturing companies, 144 useable responses were received giving a response rate of 36 %. The data were analyzed using SmartPLS, a second-generation statistical tool.FindingsThe findings of this study showed that information quality, information security, and information technology (IT) had a positive effect on SCII with an explanatory power of 47.2 % while SCII, in turn, had a positive effect on operational performance explaining 17% of the variance. Intentional information leakage (IIL) moderated the relationship between SCII and operational performance, whereas accidental information leakage did not moderate the same relationship.Practical implicationsThis study provides insights into difficulties faced when implementing SCII, particularly by medium and large manufacturing companies in Malaysia. It helps identify appropriate strategies that can guide the management in its effort to improve performance by SCII.Originality/valueThis research is arguably the first study that simultaneously investigates the effect of information quality, IT, and information security on SCII and the moderating effect of information leakage on the relationships between SCII and operational performance. The results of this study indicate that information security has the largest impact on SCII, followed by IT, and information quality. Furthermore, IIL as a negative aspect of information integration may deprive the strength of the relationship between SCII and operational performance.     

Effects of age and gender on maximum voluntary range of motion of the upper body joints

The maximum voluntary range of motion (ROM) of the major joints of the upper body was studied in a seated position and compared between young and elderly subjects. A total of 41 subjects (22 young male and female subjects aged 25 to 35 years, 19 elderly male and female subjects aged 65 to 80 years) took part in the experiment. In total, 13 maximum voluntary joint motions were performed by each subject. Age was found to have a non-uniform effect on the ROM of the joints investigated in this study. Its effect on ROM was joint specific and motion specific. The highest loss in ROM was observed in the neck and trunk, especially for neck extension, lateral flexion and axial rotation as well as for trunk lateral flexion and axial rotation. No significant age differences were observed in the elbow and wrist joint ROMs. The effect of gender on joint ROM was much weaker than that of age. Only four among the 26 joint ROMs investigated in this study were significantly different between the two gender groups.     

基于非线性回归方程偏导数分析应用程序性能敏感度的方法

性能敏感度反映了应用程序性能相对于性能影响因素的变化率,对性能敏感度的量化分析可为体系结构设计和程序性能优化提供有意义的参考和指导.提出了一种分析程序性能敏感度的非线性回归模型(PS-NLRM),能够量化不同应用程序的性能敏感度.通过主成分分析消除了影响性能的性能事件之间的相关性,通过曲线拟合引入非线性项,建立了程序性能CPI和性能事件之间的非线性回归方程.模型应用在SPEC CPU2006整型程序之上,通过了t检验和F检验,达到90%以上的拟合度.基于非线性回归方程相对于性能事件的偏导数,得到不同应用程序的性能对性能事件的敏感度.利用性能敏感度对SPEC CPU2006整型程序性能进行预测的平均相对误差约为4.5%,比传统线性回归模型预测误差下降50%.     

基于压力垫系统的人体压力中心估计方法研究

为研究压力垫在静态平衡和步态检测两个方面替代测力台的可行性,深入比较了利用压力垫和测力台计算得到的压力中心(COP)的异同。利用了平衡功能综合测力台,其包括测量分布力的压力垫系统和集总力测力台系统;这两个系统同步采样,确保测量结果得以相互比较。18名被试者以双脚直立、倾斜、左右摇晃和单脚站立等站立姿态完成测试。并且通过被试者的步态数据利用线性回归的方法,建立行走中的压力中心坐标与压力敏感单元的模型。通过t-检验和相关系数来分析比较两个测量系统得到的结果;并且验证所建立的线性回归模型的准确性。经实验验证,两个系统计算得到的COP具有较高的一致性;分析比对结果表明按足底解剖结构放置8个压敏单元能够较为准确反映压力中心的动摇轨迹。     

Geometric calibration of industrial robots using enhanced partial pose measurements and design of experiments

The paper deals with geometric calibration of industrial robots and focuses on reduction of the measurement noise impact by means of proper selection of the manipulator configurations in calibration experiments. Particular attention is paid to the enhancement of measurement and optimization techniques employed in geometric parameter identification. The developed method implements a complete and irreducible geometric model for serial manipulator, which takes into account different sources of errors (link lengths, joint offsets, etc). In contrast to other works, a new industry-oriented performance measure is proposed for optimal measurement configuration selection that improves the existing techniques via using the direct measurement data only. This new approach is aimed at finding the calibration configurations that ensure the best robot positioning accuracy after geometric error compensation. Experimental study of heavy industrial robot KUKA KR-270 illustrates the benefits of the developed pose strategy technique and the corresponding accuracy improvement.     

The effects of release height on center of pressure and trunk muscle response following sudden release of stoop lifting tasks

Background and objectives: Sudden release of load during lifting threatens postural stability and is countered by trunk muscle response, which can generate high loads on the spine, and may be a cause of tissue injury. The postural threat following sudden release and the consequent muscular response are likely to depend on the posture at the time of release. This study investigates the effects of sudden release of load at two release heights of one- and three-quarters of the knee to shoulder distance during stoop lifting.

Methods: Ten normal southern Chinese male volunteers were subject to sudden release of 20, 40, 60 and 80 N loads during stoop lifting trials. The release was randomly selected to be on the third, fourth or fifth cycle of a trial and was triggered at heights of one- and three-quarters of the total knee to shoulder lifting distance. The subjects stood on a force platform to allow the postural disturbance to be recorded by monitoring the center of pressure (COP), and electromyographic (EMG) data were collected from the rectus abdominus, internal oblique, external oblique, erector spinae and latissimus dorsi muscle groups.

Results: The COP excursion moved closer to the posterior limit of stability with increasing release load, and this effect was significantly more marked for release from the lower of the two heights. The minimum posterior COP separation from the posterior limit of stability was significantly less for the lower release height at all loads (p<0.001 in all cases). EMG data showed that the agonist–antagonist co-contraction durations were higher for the lower release height, and unlike sudden release from the higher level, showed a significant increase with increasing load.

Conclusions: Sudden release at lower release height during stoop lifting results in significantly greater postural disturbance and spinal loading. The mean load predicted to result in fall or stumble at the lower release height (133 N) is significantly less than that predicted at the higher of the two release heights (245 N). A more marked effect of release load is also seen in the postural disturbance and trunk muscle co-contraction time for the lower release height, and particular care should therefore be taken when handling potentially unstable loads under these conditions. If the security of the load cannot be guaranteed, storage at a higher level may reduce the risk of injury due to sudden release of the load.     

宽温区工作压力传感器热力学研究

介绍了硅-蓝宝石压力传感器的钛合金-蓝宝石复合弹性膜片在宽温区工作时温度变化材料不匹配引起的结构热应力,对弹性膜片的受热情况进行了分析,对不同结构形式传感器热稳定性影响程度进行了对比,利用P型掺杂硅温度特性减少结构热应力影响、降低传感器的热零点漂移.通过膜片结构选择和设计、材料选择、工艺优化和控制等可以使硅-蓝宝石压力传感器在-55~350℃宽温度范围内工作时热漂移不大于0.015%FS/℃,提高了宽温区工作时传感器的热稳定性.     

The effect of psychological risk elements on pilot flight operational performance

This study aims to examine the relationship between psychological risk elements and flight operation performance for airline pilots. First, the concept of “risky pilots” is discussed, and the existence of “risky pilots” is verified using a percentage analysis of flight exceedance events. Second, three psychological risk elements for pilots are investigated using an implementation of psychological scales, and the exceedance behaviors of risky pilots are analyzed based on real flight data. Finally, correlation and cluster analyses are used to study the influence of psychological risk elements on the exceedance behaviors of airline transport pilots and their operational performance. The results indicate that approximately one‐third of pilots are more prone to exceedance events than other pilots. A moderate positive linear correlation (R [44] = 0.400; p < .05) existed between hazardous attitudes and severe exceedance rates. For pilots with a high level of risk psychology, of their flights were considered “poor” operational performance level. Finally, it is concluded that hazardous attitude is a psychological risk element that has significant negative effects on severe exceedance behaviors of pilots. In addition, the flight operation performance levels of pilots were also affected by the psychological risk level. Furthermore, it is suggested that special training to improve risky hazardous attitudes of pilots should be conducted for the purpose of reducing exceedance behaviors and improving flight performance. These findings are expected to provide support for airlines to identify and manage flight crew risks.     

The influence of colour on CRT reading performance and subjective comfort under operational conditions

Performance and reports of comfort when proof-reading text displayed on a CRT were investigated as a function of the text/background colour. Luminances were those typically produced by commercially available hardware and software, and task conditions were designed to simulate those experienced by typical users. Colours from the extremes of the spectrum (red, blue) were shown to produce poorer reading performance, higher ratings of discomfort and a higher incidence of reported symptoms of discomfort than those from mid-spectrum and white stimulus conditions.     

The effects of ergonomic interventions on low back moments are attenuated by changes in lifting behaviour

This study investigated the effects of ergonomic interventions involving a reduction of the mass (from 16 to 11 and 6 kg) and an increase in the initial lifting height (from pallet height to 90 cm above the ground) of building blocks in a mock-up of an industrial depalletizing task, investigating lifting behaviour as well as low back moments (calculated using a 3-D linked segment model). Nine experienced construction workers participated in the experiment, in which they removed building blocks from a pallet in the way they normally did during their work. Most of the changes in lifting behaviour that were found would attenuate the effect of the investigated interventions on low back moments. When block mass was reduced from 16 to 6 kg, subjects chose to lift the building block from a 10 (SD 10) cm greater distance from the front edge of the pallet and with a 100 (SD 66) degrees/s² higher trunk angular acceleration. When initial lifting height was increased, subjects chose to shift the building blocks less before actually lifting them, resulting in a 10.7 (SD 10) cm increase in horizontal distance of the building blocks relative to the body at the instant of peak net total moment. Despite these changes in lifting behaviour, the investigated ergonomic interventions still reduced the net total low back moment (by 4.9 (SD 2.0) Nm/kg when block mass was reduced and 53.6 (SD 41.0) Nm when initial lifting height was increased).     

Evolution of the impact of e-business technology on operational competence and firm profitability: A panel data investigation

This study examines the evolution of the impact of e-business technology on operational competence and profitability using a panel dataset of 154 Spanish firms. We find that (1) e-business technology has a positive effect on operational competence that decreases over time and (2) the firm’s proficiency in exploiting a portfolio of operational capabilities has a positive impact on profitability that becomes more substantial over time. The findings provide some insights on how the initial and subsequent IT investments affect operational competence and profitability over time. This study methodologically illustrates how to perform a partial least squares estimation using panel data.     

基于LabVIEW的温度压力采集系统的设计

阐述了虚拟仪器软件开发平台LabVIEW技术的特点,并介绍了MySQL数据库与LabVIEW之间的通信方法,应用LabVIEW图形化编程软件和MySQL数据库软件,借助ODBC驱动软件,对温度、压力采集系统进行了设计,实现了温度、压力的采集,数据存储与查询,远程监控等功能。     

The effects of a lower body exoskeleton load carriage assistive device on limits of stability and postural sway

The study investigated the effects of using a lower body prototype exoskeleton (EXO) on static limits of stability and postural sway. Measurements were taken with participants, 10 US Army enlisted men, standing on a force platform. The men were tested with and without the EXO (15 kg) while carrying military loads of 20, 40 and 55 kg. Body lean to the left and right was significantly less and postural sway excursions and maximal range of movement were significantly reduced when the EXO was used. Hurst values indicated that body sway was less random over short-term time intervals and more random over long-term intervals with the EXO than without it. Feedback to the user's balance control mechanisms most likely was changed with the EXO. The reduced sway and relatively small changes in sway with increasing load weights suggest that the EXO structure may have functioned to provide a bracing effect on the body.