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The design of the Advanced Combat Helmet (ACH) currently in use was optimized by its designers in order to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface/head collisions. Since traumatic brain injury experienced by a significant fraction of the soldiers returning from the recent conflicts is associated with their exposure to blast, the ACH should be redesigned in order to provide the necessary level of protection against blast loads. The paper aims to discuss this issue.

In the present work, an augmentation of the ACH for improved blast protection is considered. This augmentation includes the use of a polyurea (a nano-segregated elastomeric copolymer) based ACH external coating. To demonstrate the efficacy of this approach, blast experiments are carried out on instrumented head-mannequins (without protection, protected using a standard ACH, and protected using an ACH augmented by a polyurea explosive-resistant coating (ERC)). These experimental efforts are complemented with the appropriate combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction finite-element analysis.

The results obtained clearly demonstrated that the use of an ERC on an ACH affects (generally in a beneficial way) head-mannequin dynamic loading and kinematic response as quantified by the intracranial pressure, impulse, acceleration and jolt.

To the authors’ knowledge, the present work is the first reported combined experimental/computational study of the blast-protection efficacy and the mild traumatic brain-injury mitigation potential of polyurea when used as an external coating on a helmet.

The purpose of this paper is to identify the musculoskeletal problems faced by the workers carrying out head lifting at the construction sites and to present a solution for the identified problems.

The methodology of the paper is framed in two phases. First, the identification of the problems faced by workers through interviews/questionnaire and second, designing and fabricating a mechanical system to safe guard workers against musculoskeletal disorders.

Based upon the interviews and questionnaires, it was ascertained that majority of the workers were subjected to neck pain and low back pain. This was mainly attributed to the lifting of heavy loads on head, sudden and jerky movements and bad postures.

The developed frame has been appreciated by the Physiotherapists also; however, it still has certain limitations which can be taken as a future scope for the further modification of the frame. The limitations are as follows: the weight of the frame is a limitation, as the worker has to bear this load in addition to the load which is to be lifted. However, this can be dealt with by replacing the material of the frame with lightweight materials such as aluminium alloys, carbon fibres, etc. The continuous wearing of the frame may result in discomfort, as the worker cannot freely roam around. Sweating and etching due to wearing of belt. Worker cannot place the load him/herself on the frame. Stability issues in lifting liquids overhead.

Findings revealed the bleak possibility of replacing head loading. However, there is an urgent need of developing a cost-effective system which could help workers while carrying out head lifting of loads.

This work presents an ergonomically designed mechanical frame which will help workers in carrying out head loading without effecting their skull, spine, etc. The system was tested on workers and the results were alarming and the working capacity of the workers was observed to increase with the fabricated frame.

The purpose of this paper is to optimize the design of the advanced combat helmet (ACH) currently in use, by its designers in order to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface/head collisions. Since traumatic brain injury experienced by a significant fraction of the soldiers returning from the recent conflicts is associated with their exposure to blast, the ACH should be redesigned in order to provide the necessary level of protection against blast loads. In the present work, augmentations of the ACH for improved blast protections are considered. These augmentations include the use of a polyurea (a nano-segregated elastomeric copolymer)-based ACH external coating/internal lining.

To demonstrate the efficacy of this approach, instrumented (unprotected, standard-ACH-protected, and augmented-ACH-protected) head-mannequin blast experiments are carried out. These experimental efforts are complemented with the appropriate combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction analysis.

The results obtained indicated that: when the extent of peak over-pressure reduction is used as a measure of the blast-mitigation effectiveness, polyurea-based augmentations do not noticeably improve, and sometimes slightly worsen, the performance of the standard ACH; when the extent of specific impulse reduction is used as a measure of the blast-mitigation effectiveness, application of the polyurea external coating to the standard ACH improves the blast-mitigation effectiveness of the helmet, particularly at shorter values of the charge-detonation standoff distance (SOD). At longer SODs, the effects of the polyurea-based ACH augmentations on the blast-mitigation efficacy of the standard ACH are inconclusive; and the use of the standard ACH significantly lowers the accelerations experienced by the skull and the intracranial matter. As far as the polyurea-based augmentations are concerned, only the internal lining at shorter SODs appears to yield additional reductions in the head accelerations.

To the authors’ knowledge, the present work contains the first report of a combined experimental/computational study addressing the problem of blast-mitigation by polyurea-based augmentation of ACH.

Since construction workers often need to carry various types of loads in their daily routine, they are at risk of sustaining musculoskeletal injuries. Additionally, carrying a load during walking may disturb their walking balance and lead to fall injuries among construction workers. Different load carrying techniques may also cause different extents of physical exertion. Therefore, the purpose of this paper is to examine the effects of different load-carrying techniques on gait parameters, dynamic balance, and physiological parameters in asymptomatic individuals on both stable and unstable surfaces.

Fifteen asymptomatic male participants (mean age: 31.5 ± 2.6 years) walked along an 8-m walkway on flat and foam surfaces with and without a load thrice using three different techniques (e.g. load carriage on the head, on the dominant shoulder, and in both hands). Temporal gait parameters (e.g. gait speed, cadence, and double support time), gait symmetry (e.g. step time, stance time, and swing time symmetry), and dynamic balance parameters [e.g. anteroposterior and mediolateral center of pressure (CoP) displacement, and CoP velocity] were evaluated. Additionally, the heart rate (HR) and electrodermal activity (EDA) was assessed to estimate physiological parameters.

The gait speed was significantly higher when the load was carried in both hands compared to other techniques (Hand load, 1.02 ms vs Head load, 0.82 ms vs Shoulder load, 0.78 ms). Stride frequency was significantly decreased during load carrying on the head than the load in both hands (46.5 vs 51.7 strides/m). Step, stance, and swing time symmetry were significantly poorer during load carrying on the shoulder than the load in both hands (Step time symmetry ration, 1.10 vs 1.04; Stance time symmetry ratio, 1.11 vs 1.05; Swing time symmetry ratio, 1.11 vs 1.04). The anteroposterior (Shoulder load, 17.47 mm vs Head load, 21.10 mm vs Hand load, −5.10 mm) and mediolateral CoP displacements (Shoulder load, −0.57 mm vs Head load, −1.53 mm vs Hand load, −3.37 ms) significantly increased during load carrying on the shoulder or head compared to a load in both hands. The HR (Head load, 85.2 beats/m vs Shoulder load, 77.5 beats/m vs No load, 69.5 beats/m) and EDA (Hand load, 14.0 µS vs Head load, 14.3 µS vs Shoulder load, 14.1 µS vs No load, 9.0 µS) were significantly larger during load carrying than no load.

The findings suggest that carrying loads in both hands yields better gait symmetry and dynamic balance than carrying loads on the dominant shoulder or head. Construction managers/instructors should recommend construction workers to carry loads in both hands to improve their gait symmetry and dynamic balance and to lower their risk of falls.

The potential changes in gait and balance parameters during various load carrying methods will aid the assessment of fall risk in construction workers during loaded walking. Wearable insole sensors that monitor gait and balance in real-time would enable safety managers to identify workers who are at risk of falling during load carriage due to various reasons (e.g. physical exertion, improper carrying techniques, fatigue). Such technology can also empower them to take the necessary steps to prevent falls.

This is the first study to use wearable insole sensors and a photoplethysmography device to assess the impacts of various load carrying approaches on gait parameters, dynamic balance, and physiological measures (i.e. HR and EDA) while walking on stable and unstable terrains.

Piles often carry combination of axial and lateral. Currently, piles are designed separately for axial and lateral load. In the literature, few information is available on the influence of axial load on lateral behaviour of the pile. This paper aims to present the results of load deformation of a pile under pure lateral load and combined axial and lateral load.

The field load tests were carried out on four different pile diameters at two different bridge sites. Moreover, the paper addresses the numerical simulation of filed load test carried out on the pile under the combination of axial and horizontal load.

After field load tests and numerical simulation, it was found that the vertical load had a remarkable effect on the lateral load response of a pile. The lateral deflection of the pile was decreased about 25% under the effect of vertical load. In addition to this, the results from field and numerical simulation are quite comparable.

Typical field load tests were simulated numerically. This research adds a value in the areas of pile foundation subjected to vertical and lateral load particularly for structure such as transmission line tower and jetty.

The £6 million engine and cylinder head assembly lines supplied by John Brown Automation for Rover's new K‐series engine are selectively automated at stations to achieve consistency and reliability.

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper is to improve existing structural performance or to return the original design performance, during refurbishment. The research aims to investigate the potential for enhanced flexural strength and toughness in concrete beams, which may be required for change of use of buildings, where loadings may be subject to change. Buildings in earthquake zones may also benefit from additional toughness provided with external fabric/yarn reinforcement as a means of providing additional time for escape, for the occupants.

The test compared four types of concrete beams with different reinforcement material compositions and each set consisted of three beams. The beams were: plain reinforced concrete without any external form of reinforcement (RC), plain unreinforced beams with a para aramid sheet (KF), plain unreinforced beams with para aramid strips of yarn attached longitudinally (KY) and plain reinforced concrete beams with sheet fabric (RCKF). All of the para‐aramid material (fabric and yarn) was externally bonded to the samples, using a two part epoxy resin adhesive applied to a prepared surface. To determine the flexural strength and toughness a three point loading test was used to provide load and deflection data on the 12 (500 mm×100 mm×100 mm) concrete beams.

An increase in flexural strength and toughness was observed when para‐aramid was used in conjunction with steel reinforcement bar (re‐bar). The para‐aramid fabric and yarn produced similar results to the plain reinforced concrete beam in terms of flexural strength but not toughness.

An advantage of using para‐aramid as an external reinforcement, would be to utilise the large deflection the beam sustains under loading, whilst the fabric/yarn holds the beam together across the rupture plane. Although the testing did not prove that para‐aramid would be a viable alternative to steel re‐bar it did show that the material has the potential as an additional reinforcement that may be particularly useful where concrete structures are subject to large deformations or in need of repair.

In the first two articles the past trends of improvement in air safety were discussed. The indications for the short term future are that replacement of the older aircraft remaining in the world fleets by modern types will lead to continued improvement. However, if an upward trend is to be maintained long term, then new types of aircraft will have to offer specific advances in airworthiness, and in parallel further improvements in operational procedures made. This article looks at the prospects and the constraints.

Details of Some Components Used for Subsidiary Services in Aircraft, Missiles and Space Vehicles. W & T Avery Ltd. have introduced a machine for bi‐directional testing into their new range of standard hydraulic servo‐controlled testing machines. Designated the type 7151CSB/DSB, this equipment enables cither tension or compression to be applied and loads to be varied from tension through zero to compression and vice versa. It is available in English capacities of 50,000 lbf., 150,000 lbf., 20 tonf. and 60 tonf. and metric capacities of 20,000 kgf. and 60,000 kgf.

The purpose of this paper is to investigate, experimentally and numerically, the pressure pulse characteristics and unsteady flow behavior in a Francis turbine runner for moderate flow heads. The pressure pulses in the runner blade passage were predicted numerically for both moderate and high heads. The calculations were used to partition the turbine operating regions and to clarify the various for the unsteady flow behavior, especially the blade channel vortex in the runner.

Experimental and numerical analyses of pressure pulse characteristics at moderate flow heads in a Francis turbine runner were then extended to high heads through numerical modeling with 3D unsteady numerical simulations performed for a number of operating conditions. The unsteady Reynolds‐averaged Navier‐Stokes equations with the k‐ω‐based shear stress transport turbulence model were used to model the unsteady flow within the entire flow passage of a Francis turbine.

The dominate frequency of the predicted pressure pulses at runner inlet agree with the experimental results in the head cover at moderate flow heads. The influence of the blade passing frequency causes the simulated peak‐to‐peak amplitudes in the runner inlet to be larger than in the head cover. The measured and predicted pressure pulses at different positions along the runner are comparable. At the most unstable operating condition of 0.5a₀ guide vane opening, the pressure pulses in the runner blade passage are due to the blade channel vortex and the rotor‐stator interference. The predictions show that the frequency of the blade channel vortex is relatively low and it changes with the operating conditions.

The paper describes a study which experimentally and numerically investigated the pressure pulses characteristics in a Francis turbine runner at moderate flow heads. The pulse characteristics and unsteady flow behavior due to the blade channel vortex in the runner at high heads were investigated numerically, with the turbine operating regions then partitioned to identify safe operating regions.