Effects of Pause Design on the Decline in Pulling Effort and the Evaluation of Perceived Effort in Pulling Tasks

Pulling is one of the manual material handling activities that could lead to work-related musculoskeletal disorders. The objectives of this study were to explore the development of muscular fatigue when performing intermittent pulling tasks and to establish models to predict the pull strength decrease due to performing the tasks. A simulated truck pulling experiment was conducted. Eleven healthy male adults participated. The participants pulled a handle with a load of 40 kg, which resulted in a pulling force of approximately 123 N. The pulling tasks lasted for 9 or 12 min with one, two, or three pauses embedded. The total time period of the embedded pauses was 3 min. The pull strength after each pull and rest was measured. Ratings of the perceived exertion on body parts after each pull were also recorded. The results showed insignificant differences regarding the development of muscular fatigue related to rest frequency. We found that the development of muscular fatigue for pulling tasks with embedded pauses was significantly slower than that for continuous pulls. The forearm had a higher CR-10 score than the other body parts indicating that the forearm was the body part suffering early muscle fatigue. An exponential model was developed to predict the pull strength of the pulling tasks with embedded pauses. This model may be used to assess the developing of muscular fatigue for pulling tasks.

Isometric push and pull strengths of agricultural workers from Northeast India

BACKGROUND: In agricultural farming operations, the incompatibility between operators’ physical capability and labor demands in the operation of tools and equipment results in a decreased performance, productivity, and safety related measures. OBJECTIVE: The aim of this study was to collect a biomechanical database of push/pull strengths for initiating the development of a human-centered design of equipment that is not available for the intended user group, i.e. Nagaland. METHODS: The sample consisted of 399 male and 271 female agricultural workers from the five districts of Nagaland, aged 18 to 65 years, classified into three age groups. In the process of push and pull force measurements, the elbow angle of the participants were set to 30–120°, 120–130°, and 130–180°. All tests were performed in triplicates with a resting period of two minutes between every consequent recording. RESULTS: The results showed that isometric push and pull strength values (Mean±SD) for males were 18.91±4.67 kg and 17.98±3.97 kg respectively and 13.07±4.06 kg and 11.98±3.33 kg for females respectively. The results of independent samples from student’s t-test demonstrate that there was a substantial variance in the isometric push and pull strength values (p < 0.05) between the genders across the various age spectrum. CONCLUSIONS: With ageing, muscular strength for push-pull strength in males and females reduce. The study reports that the recommended value of male and female isometric push-pull strength for agricultural workers of Nagaland should be 5th percentile of female data i.e. 6.40 and 1.71 kg respectively.

Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting?

Inappropriate leash reactivity is one of the most common problems in shelter dogs, which negatively affects the health of dogs and reduces their adoptability. We explored 370 human-dog interactions, involving 74 volunteers and 111 dogs, in an animal shelter when volunteers walked shelter dogs on a leash, considering the effects of canine demographics and the results of the shelter’s canine behavioural assessments. The interaction was video recorded and coded using ethograms, and a leash tension meter was used to measure the pull strength of dogs and handlers. Results showed that dogs that were more relaxed during the shelter assessment (i.e., when socialising with humans or being left alone in a new environment) were less reactive on the leash, with lower tension and pulling frequency. Moreover, socialised and relaxed dogs displayed more positive body language, such as tail in a high position, gazing at the handler, and exploring the environment. When walking with these dogs, volunteers utilised fewer verbal cues and body language during the walk. In addition to the canine behaviour assessment, there were correlations between canine demographics and the behavioural interaction and humans’ perception. Finally, volunteers perceived the walk as less satisfactory when they needed to pull the leash harder during the walk. This research suggests that the RSPCA behavioural assessment may be useful in predicting the behaviour of shelter dogs when walked by volunteers.

Who Is Pulling the Leash? Effects of Human Gender and Dog Sex on Human–Dog Dyads When Walking On-Leash

Previous studies have indicated that human gender and canine sex influences human–dog interactions. However, the majority of studies have considered the interaction when dogs were off-leash and the behavioural interactions when dogs are walked on a leash have not been addressed. This study investigated human–dog interactions when shelter volunteers take shelter dogs for an on-leash walk. Video records were made of 370 walks, involving 74 volunteers and 111 shelter dogs, and a leash tension meter was used to determine the pull strength of dogs and walkers. Human gender and canine sex had dyadic effects during the walk. Male dogs tended to pull more frequently and created increased leash tensions. Dogs displayed more stress related behaviours when interacting with men than women, with the signs being spending less time holding the tail in the high position, and more frequent gazing and lip-licking behaviours. Finally, there was a greater pre-disposition in women to use verbal commands, and language typically used with babies, while men were more inclined to have physical contact with dogs. This study’s results may be used to match shelter dogs with appropriate men and women volunteers for walking exercise of the dog, and to improve potential dog socialisation efforts by shelters.

Improving the Adhesiveness of Cemented Glass Components by DBD Plasma Pre-Treatment at Atmospheric Pressure

Cemented optical components and groups are essential devices for the realisation of modern systems and apparatuses used in a broad range of different applications such as telecommunications, imaging and even surgery. However, various parameters may affect the stability of cemented connections. In this context, the impact of dielectric barrier discharge plasma at atmospheric pressure on the adhesiveness of cemented glass components was evaluated in the present work. For this purpose, the plasma-induced change in surface wettability and energy as well as the cement’s adhesive pull strength was measured. Investigations were performed on samples, which were subject to different procedures of artificial ageing. It is shown that the adhesive pull strength of cemented glass components was notably increased after a short-term plasma treatment of merely 10 s due to an enhanced wettability of the applied UV-curing optical cement. The pull strength, i.e., the adhesiveness of cemented glasses was increased by a factor of 2.1 to 4.6, depending on the particularly applied artificial ageing procedure. The results and findings finally demonstrate the high potential of the applied short-term plasma treatment as a cleaning and surface activation step in optics manufacturing on an industrial scale.