Strap Length Research Articles

Semiconductor Effect from Pd(II) Porphyrin Metal to Its Ligand in Photocatalytic N-Dealkylation.

In this work, four saddled Pd(II) porphyrins were developed as photocatalyst for N-dealkylation of triethyl Rhodamine (TER) under visible light, and their catalytic ability was found to be negatively related to the out-of-plane of their macrocycles. Two important relationships involving the metalloporphyrins as catalyst were revealed: (1) a photoexcitative semiconductor effect between the 4dx 2-γ 2(Pd) and a2u(π) orbitals of Pd(II) porphyrin on the dealkylation. (2) a domino process from strap length, ring geometry, core deformation, d-π gap variation, to photocatalytic activity. Two revelations imply a unidirectional electron transfer route from axial ligand, to central metal, to porphyrin ring based on photoexcitation and guide the design and development of complex photocatalysts, and their revelation is attributed to the acquisition of a series of Pd(II) porphyrins with continuous ring distortion. The findings help to understand the photocatalytic single electron transfer (SET)-first mechanism based on metallic complex.

Determination of dynamic air gap thickness and analysis of its relationship with firefighters’ joint movement

ABSTRACT Objectives. The purpose of this study was to calculate the dynamic air gap thickness between the human body and the turnout gear. Relationships between the air gap thickness and joint range of motion (ROM) were also explored. Methods. The air gap thickness and joint ROM of 12 male firefighters walking in a control condition with no self-contained breathing apparatus (SCBA) and three varying-strapped SCBAs were measured using three-dimensional (3D) body scanning and 3D inertial motion capture. The interpolation technique was employed to predict the air gap thickness curve during walking. The dynamic air gap thickness was compared with the joint ROM to see how they relate to the location and percentage of movement restriction. Results. During the walking, the air gap fluctuated as a sine curve. Carrying SCBA reduced the air gap thickness at the trunk most (F = 11.17, p < 0.001, η 2 = 0.63), and adjusting the shoulder strap length altered the air gap distribution at the trunk. The reduced air gap at the pelvis caused an incremental restriction on pelvis rotation. Conclusions. A compatibility design of the shoulder strap and hip belt in SCBA with the turnout jacket is suggested.

Utilization of Anthropometric Data to Determine Strap Length for Rattan Shoulder Bag Products in Indonesia

The straps of rattan bag handicraft products in Indonesia have different shapes and sizes. This can be observed from the straps of rattan shoulder bags designed to have a permanent size, leading to the lack of flexibility in increasing or decreasing the length of the bag to fit the height of the users. Therefore, this study aimed to design a standard ergonomic strap length for rattan shoulder bags in order to ensure compatibility with small, medium, and large-sized users in Indonesia. The process was conducted through the retrieval of anthropometric data for women between the ages of 17 and 45 years for calculations. The results showed that 60 cm was the appropriate length for small-sized users, 85 cm for medium, and 100 cm for large. The implication of the results was to provide support for the production of different strap length designs based on the differences in the type of bag and body size. Moreover, the results contributed to the rattan handicraft industry by providing recommendation on the standard strap lengths for shoulder bags to be produced.

Ergonomic Design of Anjat Rattan Sling Bag Strap Products in Indonesia

Anjat is a backpack or tote bag made of rattan which is the result of woven handicrafts from the Dayak tribe in Kalimantan. This type of Anjat developed into several types of smaller bags, one of which is in the form of a sling bag. One of the important things in the Anjat production process is the design of the length of the sling bag strap. The strap of this rattan sling bag cannot be adjusted because it cannot be extended or shortened according to the user's needs. This is because the rattan woven binding system at the end of the bag strap on the body of the bag is permanent. It is very important to determine the right bag strap length for a rattan sling bag that is in accordance with the anthropometric data of users in Indonesia. This study aims to design a long strap sling bag made of rattan that is in accordance with Indonesian human anthropometry. This research method uses calculations using Indonesian anthropometric data for women aged 17-45 years to determine 3 sizes of sling bag straps, namely the 5th percentile (small size), the 50th percentile (medium size) and the 95th percentile (large size). The contribution of this research is to provide input for small and medium industries that make Anjat types of rattan sling bags in the form of recommendations on the size of the ergonomic sling bag strap according to the anthropometry of the human body in Indonesia. This study provides recommendations for sling bag strap lengths of 80 cm, 100 cm and 140 cm for small, medium, and large sizes.

Evaluation of properties of elastomeric head straps of filtering facepiece respirators

Frequent donning and doffing of filtering facepiece respirators (FFRs) can reduce their effectiveness due to the residual deformation of their elastic head straps. This study investigates the loss of elasticity of head straps during repeated use. Five elastomeric tapes were tested as FFR head straps, and their tensile strength was measured using a DU-100 dynamometer after repeated donning and doffing cycles. After eight consecutive uses, the protection factor drops significantly, requiring strap length adjustments to guarantee the specified level of user protection. The maximum tensile force of the elastomeric head straps causes residual elongation, which remains consistent after eight cycles. The study also establishes how strap elongation depends on the force and number of donning and doffing cycles. This knowledge is vital for designing better FFRs. Additionally, the research explores alternative materials for FFR construction to address strap elongation and its effects on performance and comfort.

A biomechanical evaluation of firefighters’ musculoskeletal loads when carrying self-contained breathing apparatus in walking and running

Introduction: Musculoskeletal loading data are needed to design ergonomic intervention for firefighters. This study aimed to quantify the firefighters’ musculoskeletal loads during self-contained breathing apparatus (SCBA) carriage and evaluate the effectiveness of shoulder strap length variation for the prevention of SCBA-related injuries. Method: Twelve firefighters (height: 174.6 ± 2.4 cm, mass: 67 ± 3.5 kg, BMI = 22 ± 1 kg/m2) participated the walking and running protocols with no SCBA equipped and three varying-strapped SCBAs conditions. Joint range of motion and surface electromyography (sEMG) were synchronously measured. Subsequently, joint kinematics was inputted for subject-specific musculoskeletal modeling to estimate muscle forces and joint reaction forces, while the sEMG was used to validate the model. Repeated measures analysis of variance was used for the main effects (p < 0.05). Independent samples t-test was performed to determine differences between walking and running. Results: Walking with SCBA increased the rectus femoris force and hip reaction force by 34.92% [F = 53.629; p < 0.001; η2 = 0.317] and 34.71% [F = 53.653; p < 0.001; η2 = 0.517], the growth rate was 54.2% [F = 76.487; p < 0.001; η2 = 0.418] and 51.19% [F = 69.201; p < 0.001; η2 = 0.652] during running, respectively. Running with SCBA significantly increased the knee reaction force by 63.04% [F = 83.960; p < 0.001; η2 = 0.797], while only 18.49% increase during walking. Adjusting SCBA shoulder strap length significantly altered the rectus abdominis force and L4/L5 reaction force during walking and running. Conclusions: Results revealed that rectus femoris activity, hip and knee exertion was sensitive to SCBA carriage. The variation of shoulder strap length has potential to influence the risk of low back pain (LBP). Practical applications: The findings suggest that fire services promote targeting physical training at firefighters’ hip and knee regions. Test firefighters in this study were not advisable to adjust their shoulder strap at loose-fitting condition. The compatibility design of the trunk morphology and SCBA back-mounted frame was suggested for the management of LBP.

Design and Performance Research of a Wearable Airbag for the Human Body

In this paper, an integrated wearable airbag is proposed to protect the vulnerable pedestrian during a vehicle–pedestrian collision accident. To evaluate the protection performance of this newly proposed integrated wearable airbag, the airbag inflator finite element model is first verified via an inflator tank test, and the simulated results agree very well with the test. Next, the finite element model of the vehicle–pedestrian model is established, including a simplified vehicle model and a biomechanical HBM with the integrated wearable airbag. The numerical results show the newly proposed wearable airbag can effectively protect the pedestrian by significantly reducing injuries to the head and chest. Since head injury is the most important injury type, a complete set of injury indexes is adopted to evaluate severity of head injury, including HIC15, 3 ms resultant acceleration, and intracranial pressure. To further improve the protection performance of the airbag on the HBM’s head, a parametric study is conducted towards two design parameters of the wearable airbag: inflator gas mass and pulling strap length. The parametric investigation shows 26 g gas and a 20 mm pulling strap can provide the best protection for the HBM’s head.

Impact of Educational Intervention in Reducing the Weight of School Bags in Selected School Children.

To assess the effectiveness of educational intervention to reduce the weight of school bags. The study design was one group pre- and posttest experimental Research design. Government Senior Secondary School Dhanas, Chandigarh, and Shri Guru Harkrishan Model Senior Secondary School Sector-38D, Chandigarh (A private school) between July and November 2018. Names of the schools can be avoided. Total 760 students from selected sections nursery to 10th class of school were enrolled in the study. At baseline and end line weight of children, school bags and its content were weighed using weighing scale. Length of bag strap, breath of bag, torso of children, and their shoulders size were measured by measuring tape. Bag carrying style, posture, etc., were observed by observation checklist. Interviewed children (5th to 10th class) were using Nordic musculoskeletal questionnaire for musculoskeletal system assessment. Educational intervention was provided to the children for one month to reduce weight of school bag by teaching in assembly and displaying the charts in school. (Use of softbound thin textbooks, breaking thin books in 2-3 thin softbound books, use lightweight bag, pencil box, lunch box, and water bottles. Pack bag as per timetable.). The result revealed that heavy school bags were carrying 69.7% children from government school and 80.2% from private school. Children carrying heavy bags reported musculoskeletal problems 5 times higher than their counterparts. After intervention, there was significant reduction in the weight of school bags (P < 0.001 as per paired t-test). Provide the weight of the bags before and after intervention in addition to the P value. Children carrying heavy bags were suffering from musculoskeletal problems. Intervention helped in reducing the weight of school bag.

Numerical Simulation of Dense Solid-Liquid Mixing in Stirred Vessel with Improved Dual Axial Impeller

Computational fluid dynamics (CFDs) were adopted in order to investigate the solid suspending process in a dense solid–liquid system (with a solid volume fraction of 30%), agitated by a traditional dual axial impeller and a modified dual axial impeller, otherwise known as a dual triple blade impeller (DTBI) and a dual rigid-flexible triple blade impeller (DRFTBI), respectively. The effects of rotational speed, connection strap length/width, and off-bottom clearance on the solid distribution were investigated. The results show that the proportion of solid concentration larger than 0.4 in the DTBI system was 26.56 times of that in the DRFTBI system. This indicates that the DRFTBI system can strengthen the solid suspension and decrease the solid accumulation in the bottom of the tank. Furthermore, the velocity and turbulent kinetic energy in the DRFTBI system were promoted. In addition, for an optimal selection, the optimum length of connection strap was 1.2 H1, the optimum range of connection strap width was D/7–D/8, and the off-bottom clearance selected as T/4 was better.

Implementation of Portable Automatic Tourniquet with High-Elasticity Biocompatible Strap

The most common screening techniques to diagnose a patient’s illness are blood collection and intravenous procedures. To find a collection or injection site, conventional blood collection support tools, such as latex tubing and buckle-type tourniquets, are generally used to compress the patient’s blood vessels. This conventional passive method has significant problems such as latex allergy, vulnerability to site contamination and potential bloodstream infection, and physical damage due to improper use. To overcome the disadvantages of conventional blood collection support tools, an automatic tourniquet with a high-elasticity biocompatible strap was constructed. The automatic tourniquet is designed to automatically adjust the strap length using a motor to control the pressure according to the body dimensions of patients. In order to evaluate the performance of the automatic tourniquet, blood flow characteristics were analyzed using an ultrasound measurement system. The results demonstrated that the automatic tourniquet showed better performance compared with those of other blood collection support tools.

Self-piercing riveting for single-strap butt joints in similar aluminium alloys

The self-piercing riveting (SPR) single-strap butt joints (butt joint) were fabricated in similar sheets of Al5052 aluminium alloy and 1420 aluminium–lithium alloy. Mechanical characteristics of SPR butt joints of different materials were discussed comparing with their corresponding SPR single-lap joints (lap joint). The effects of the rivet pitch and the strap length on the butt joints of different materials were investigated. Results indicated that the lap joints have better performance in strength and stiffness, while the butt joints have more superior shock resistance capacity. The strap length had some impact on the failure behaviour of the joint but not the joint strength. The load borne capacity of the butt joints was highly dependent on rivet pitch.

Strap Performance of N95 Filtering Facepiece Respirators After Multiple Decontamination Cycles

The Battelle Critical Care Decontamination System™ (CCDS™) decontaminates N95 filtering facepiece respirators (FFRs) using vapor phase hydrogen peroxide (VPHP) for reuse when there is a critical supply shortage. The Battelle CCDS received an Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) in March 2020. This research focused on evaluating the mechanical properties of the straps as an indicator of respirator fit. The objective was to characterize the load generated by the straps following up to 20 don/doff and decontamination cycles in Battelle’s CCDS. In general, the measured loads at 50 and 100% strains after 20 cycles were similar (±15%) to the as-received controls. Qualitatively, reductions in the load may be associated with loss of elasticity in the straps, potentially reducing the ability to obtain a proper fit. However, small changes in strap elasticity may not affect the ability to obtain a proper fit given the potential for variation in strap length and positioning on the head. Regardless, prior to reusing a N95 respirator, it is important to complete a visual inspection to ensure it is not damaged, malformed, or soiled. If so, it is recommended to discard the respirator and use a different one. Similarly, the respirator should be discarded if the wearer cannot obtain a proper fit during the user seal check.

The weight of pupils\u2019 schoolbags in early school age and its influence on body posture

BackgroundPostural development progresses through a series of stages (growth spurts, development of balance and coordination, postural stability) which occur when children are at school age. The reduction in the level of physical activity, increased body weight, overloaded school bags, asymmetry of the backpack straps, the method of putting on and taking off the backpacks and increased usage of electronic devices have negative side effects such as bad body posture habits.MethodsA prospective cohort study in the group of 155 pupils at early school age 7–9 years old has been conducted. Examinations have been conducted twice: first, at the beginning of the school year (initial examination) and second – after 10–11 months (final examination). Age, gender, BMI, weight of school bag carried to school and the length of straps have been assessed. Body posture measurement (using Adams’ test), the evaluation of the plumb line deflection from the gluteal cleft, the angle values of kyphosis and lordosis (according to Dobosiewicz methodology) and the pelvis and shoulder blades position (using a ruler and pediscoliometer) have been also measured.ResultsThe mean weight of a school bag in the initial study was 6.3 ± 0.8 (range between 4,7 and 9 kg). A tendency to carry slightly heavier school bags was noted in boys (6.7 vs. 5.9 kg; p = 0,00001). This tendency has linearly changed with age (R = 0.68; p < 0,001). In 3.2% of all school bags of children, weights exceeded norms with regard to the weight of the pupil. The increase of torso rotation exceeding norms was observed in 35.3% of girls (mean 2.7 ± 1.2) and in 60.9% of boys (mean 2.3 ± 1.3). The increase of kyphosis angle was noted in 48.5% of girls and in 36.8% of boys. The difference of straps length had a significant influence on the increase of rotation in upper thoracic spine, thoracolumbar junction and it also had influence on the decrease of lumbar lordosis in the group of girls.ConclusionsDifferences in the weight of school bags after one school year have influenced changes in body posture abnormalities, especially in rotation parameters. Backpack straps asymmetry was noticeably stronger in the group of girls and the difference between braces may have an impact on some posturometric parameters. Lack of proper backpack lifting skills tends to create programs and training systems in this regard.

Three-dimensional modelling and numerical optimisation of the W7-X ICRH antenna

Ion Cyclotron Resonance Heating (ICRH) is a promising heating and wall conditioning method considered for the W7-X stellarator and a dedicated ICRH antenna has been designed. This antenna must perform several tasks in a long term physics programme: fast particles generation, heating at high densities, current drive and ICRH physics studies. Various minority heating scenarios are considered and two frequency bands will be used. In the present work a design for the low frequency range (25–38MHz) only is developed. The antenna is made of 2 straps with tap feeds and tuning capacitors with DC capacitance in the range 15–200pF. These capacitors introduce additional constraints on the optimisation and on the maximum amount of power that can be coupled to the plasma: not only the capacitor voltages cannot exceed a certain value (42kV) but also the currents are limited to approximately 740A rms to ensure sufficient heat dissipation for the considered duty cycle. Starting from an initial geometry we used the tridimensional electromagnetic software CST MicroWave Studio (MWS) to assess and optimise its coupling properties. By modifying some geometrical parameters of the front face (strap width, antenna box depth, strap length, strap feeders shape), we show that a substantial increase in maximum coupled power can be obtained accounting for the technical constraints on the capacitors. The various steps of the optimisation are validated with TOPICA simulations. For a given density profile the RF power coupling expectancy can be precisely computed.

Simulation on Injury to Driver under Car Front Crash Condition

To study the injury index to driver in front crash, this article uses the MADYMO software to establish the driver constraint system model which including car bodies, safety belts and 50% dummy for impact simulation. The simulation values are close to test ones after contrasted with the vehicle impact test. The influence of design parameters including the D-ring friction coefficient of seat belt, airbag strap and steering column on driver HIC, T3MS, THPC are researched by this model. The results show that: The smaller D-ring friction and a longer airbag strap length and steering column crushing can effectively improve the driver safety.

An Optimization Design of Knee Airbag for Driver Protection from Inter-City Coach Frontal Impact

&lt;strong&gt;In order to &lt;/strong&gt;&lt;strong&gt;reduce the injury risk of driver’s lower extremities, a driver knee airbag was de&lt;/strong&gt;&lt;strong&gt;veloped&lt;/strong&gt;&lt;strong&gt; and optimized by&lt;/strong&gt;&lt;strong&gt; using mathematical models&lt;/strong&gt;&lt;strong&gt;. The influence of eight design parameters of belt and knee airbag on the injuries of driver’s lower extremities was analyzed. The &lt;/strong&gt;&lt;strong&gt;result &lt;/strong&gt;&lt;strong&gt;shows that the key influence factors&lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;&lt;strong&gt;are&lt;/strong&gt;&lt;strong&gt; sensitive to the injuries of lower extremity&lt;/strong&gt;&lt;strong&gt;, including initiation &lt;/strong&gt;&lt;strong&gt;timing &lt;/strong&gt;&lt;strong&gt;of knee airbag,&lt;/strong&gt;&lt;strong&gt; the strap length of knee airbag and area coefficient for the exhaust openings of knee airbag&lt;/strong&gt;&lt;strong&gt;. Based on multi-objective genetic algorithms&lt;/strong&gt;&lt;strong&gt;,&lt;/strong&gt;&lt;strong&gt; an optimization of the knee airbag was conducted in terms of the three factors. After optimization, the injury risk of driver’s lower extremities is greatly reduced.&lt;/strong&gt;&lt;strong&gt;&lt;/strong&gt;

Numerical investigation on practicability of reducing MCST by using grid spacer in a tight rod bundle

The numerical investigation was carried out to reveal the practicability of reducing the maximum cladding surface temperature (MCST) within the inner sub-channel of a tight, hexagon rod bundle using commercial CFD code STAR CCM+ 6.04. The special heat transfer and pressure drop characteristics caused by four existing grid spacer designs were discussed in detail by analyzing the effects of grid strap length, different flow enhancing features and different Reynolds numbers. It was found that the local heat transfer within the grid strap is greatly enhanced due to the raised flow velocity. Both the standard grid spacer and the grid spacer with split-vanes cause decreased heat transfer in the downstream region. The friction drag is very influential in the tight rod bundle and can eliminate the positive effect of flow blockage on the heat transfer performance. The grid spacer with flow blockage discs induces relatively good heat transfer performance and higher pressure drop within sub-channels, indicating a tradeoff between the heat transfer augmentation and the pressure drop. The combination of multiple existing grid spacers can reduce the MCST to a certain level, but the corresponding disadvantages cannot be ignored. The improved grid spacer design was proposed based on the overall considerations of heat transfer and pressure drop characteristics and has been proved more suitable to widely reduce MCST for SCWR than any other grid spacer designs involved in present study.

Correlations between Muscle Activities and Strap Length and Types of School Bag during Walking.

[Purpose] The purpose of this study was to examine correlations between muscle activities and strap length and type of the school bag during walking. [Subjects and Methods] The subjects of this study were 20 healthy students. An 8-channel electromyograph (8-EMG) (Pocket EMG, BTS, Italy) was used to measure the muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae during walking with the bag. The collected data were analyzed using Kendall’s coefficient of concordance. [Results] The muscle activities of the right upper trapezius, left upper trapezius, right erector spinae and left erector spinae were significantly higher when walking with a shoulder bag than when walking with a backpack. No significant correlations were found between muscle activities and strap lengths of the bag. [Conclusion] While carrying a bag, the activities of the trunk muscles were influenced more by the type of the bag than by the strap length. These results indicate that a backpack is a better method of carrying a load than a shoulder bag.

Influence of the strap-length on the trunk motion and gait symmetry in Korean women carrying a single-strap bag

The purpose of this study was to examine whether strap length influences the trunk motion and gait symmetry of the ground reaction forces while walking with a single-strap bag. Seventeen Korean women participated in this study. The kinematics of trunk motion and ground-reaction forces was recorded while the participants walked at a self-paced speed under three conditions: no bag, a short-strap bag and a long-strap bag. The amplitude of trunk rotation on the ipsilateral side (the bag side) decreased while walking with a short-strap bag compared to walking with a long-strap bag or no bag (p< 0.05). The amplitude of trunk lateral bending toward the contralateral side and asymmetry in the mediolateral ground-reaction force significantly increased while walking with a long-strap bag compared to walking with a short-strap bag or no bag (p< 0.05). These results demonstrate that carrying a long-strap bag during walking resulted in increased trunk lateral bending and asymmetry in the mediolateral ground-reaction forces. It is therefore important to select the correct strap length when carrying a single-strap bag to prevent musculoskeletal disorders.

Anthropometry of Agricultural Workers of Madhya Pradesh

A study was undertaken to create the repository of anthropometeric data of agricultural workers of central India. Based on the population of male as well as female agricultural workers in twenty districts from nine different agro climatic zones of Madhya Pradesh (central India), data on seventy-nine identified body dimensions were collected for 1701 agricultural workers (944 male and 757 female). The selected workers were within the age group of 18-60 years with average age as 29.8 years for male and 33.7 years for female. Among the selected subjects, 7.4% male and 8.1% female workers were prominently using their left hand rather than right hand. The mean (±SD) weight and stature were 51.2±6.4 kg and 1649±59 mm for male, and 45.0±7.3 kg and 1519±54 mm for female workers, respectively. Vertical measurements had fairly good correlation with stature with coefficient of correlation(r) varying from 0.75-0.9 for both male and female workers. Similarly, vertical grip reach sitting, sitting eye height, and sitting acromion height had linear correlation with sitting height (r=0.75-0.85). The mean stature of male workers of Gujarat was higher than that of Madhya Pradesh, while the stature of all other population groups was lower. However, no such trend was observed among the female population of different states of the country. The 5th percentile values should be used for design where the lower limit is the restrictive factor such as operating forces, control reach and height of displays. The 95th percentile value should be used for design, where the upper limit is the restrictive factor such as design of clearances, seat width, backrest width and strap length for knapsack sprayers.