• Advances in materials Research
• /
• v.7 no.3
• /
• pp.185-194
• /
• 2018

The mechanism of biological materials structure is very complex and has optimal properties compared to engineering materials. Top Neck mollusks shells, as an example of biological materials, have hierarchical structure, which 95 percent of its structure is Aragonite and 5 percent organic materials. This article detected mechanical properties of the Top Neck mollusks shell as a Nano composite using Nano-indentation method in different situations. Research findings indicate that mechanical properties of the Top Neck mollusks shell including elastic modulus and hardness are higher than a fresh one preserved in -50 centigrade and also a Top Neck mollusks shell preserved in environmental conditions. Nano-indentation test results are so close in range, overall, that hardness degree is 3900 to 5200 MPa and elastic modulus is 70 to 85 GPa.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.7
• /
• pp.1058-1072
• /
• 1997

A head-neck complex dummy, for measuring brain pressure and reaction force in the cervical spine was developed for experimental study related in injury mechanism. Dummy comprised aluminium-casted head with water filled cavity for simulating brain and mechanical neck assembled with six motion segments. Several kinds of experiments (compression, bending, cyclic modulus, relaxation and constant velocity profile) for the developed mechanical neck showed that this neck model is biomechanically reliable compared with in-vitro test results. As an application of developed head-neck complex dummy, shock absorbing properties of protective helmet was chosen. The experiments showed that the maximum pressure increment of brain after impact was tolerable compared with the guide line for mild brain injury pressure (25psi). Constrast to this results, the reaction force in the neck was high enough to produce failure in the cervical spine.

• Journal of the Korean Society of Physical Medicine
• /
• v.17 no.1
• /
• pp.63-74
• /
• 2022

PURPOSE: This study aimed to compare the effects of manual therapy with stabilization exercises to manual therapy alone, on neck pain and body functions in patients with chronic mechanical neck pain. METHODS: Twenty patients with chronic mechanical neck pain were recruited and randomly allocated into two groups. A control group(n = 10) was given the manual therapy alone and an experimental group(n = 10) was given the manual therapy with stabilization exercises. The intervention was carried out 3 days per week for 4 weeks. The cervical resting pain, the most painful motion pain, craniocervical flexor endurance, forward head posture and neck disability index were used to assess participants at baseline and after 4 weeks. RESULTS: A comparison of the parameters before and after the intervention showed that both groups experienced significant improvements in the resting pain, the most painful motion pain, craniocervical flexor endurance, and forward head posture except for the forward head posture in the control group. A comparison of the parameters between the groups did not show a significant difference. CONCLUSION: The results of this study suggest that the combined intervention of manual therapy with stabilization exercise does not seem to be more effective than manual therapy alone for improving neck pain, craniocervical flexor endurance, forward head posture, and the neck disability index in patients with chronic mechanical neck pain.

• Journal of Mechanical Science and Technology
• /
• v.14 no.11
• /
• pp.1232-1243
• /
• 2000

Motor vehicle accidents in rear impacts cause more than fifty percents of drivers to suffer from neck injuries. It is known that most neck injuries are associated with rear-end collisions at a speed lower than 32 km/h and between the Abbreviated Injury Scale (AIS) 1 and AIS 2. Two different types of low speed crash tests such as the frontal barrier and rear moving barrier crashes have been conducted by following the procedure of the Research Committee for Automobile Repairs (RCAR). The injury for the neck and the Head Injury Criteria (HIC) were measured by using the sensors mounted on dummies. We reviewed neck injures and the relationship between the neck and head injuries, and examined the deceleration of the body. Using the experimental test data at the neck, we investigated an improved neck injury criterion Nij. Also, the effects of the position of a head restraint on reducing the frequency and severity of the neck injury in rear-end collisions were investigated.

• Journal of the Korean Society of Physical Medicine
• /
• v.10 no.2
• /
• pp.35-45
• /
• 2015

PURPOSE: The aim of this study is to investigate how upper thoracic manipulation and cervical stability training affects cervical range of motion and neck disability index of patients with chronic mechanical neck pain. METHODS: 30 patients with chronic mechanical neck pain, and randomly divided into the upper thoracic manipulation and the cervical stability training group. Upper thoracic manipulation group was conducted to the upper thoracic manipulation, and cervical stability training was conducted to the cervical stability training. Intervention period was 6 weeks, and 3 sessions, each of which was run for 5~10 minutes. The subjects were measured neck range of motion before and after intervention by electro-goniometer. Neck disability index was used to measure neck disability index Korean version. RESULTS: Comparison within groups, there were significant difference in neck range of motion before and after intervention, and Neck disability index significantly reduced in the cervical stability training group. The comparison between groups, there were no significant difference in neck range of motion and neck disability index. CONCLUSION: Upper thoracic manipulation and cervical stability training to the patients with chronic neck pain was helpful to improve neck range of motion and cervical stability training was helpful to improve neck disability index.

• The Journal of Korean Physical Therapy
• /
• v.32 no.2
• /
• pp.126-131
• /
• 2020

Purpose: The purpose of this study was to compare the change in pain, Neck Disability Index score, and the craniovertebral angle by performing scapular correction exercise or general neck exercise for five weeks in participants with mechanical neck pain. Methods: A total of 31 participants were randomly assigned between the scapular correction exercise and the general neck exercise groups, and all participants performed intervention for 40 minutes each, three times a week for five weeks The effects were evaluated by measuring the Visual Analog Scale score, the Neck Disability Index score, and the craniovertebral angle, before and after the intervention. Independent t-tests were used to compare differences between two groups, and to compare differences between pre- and post-intervention, paired t-tests were used. Results: As measured before and after the intervention, the scapular correction exercise group showed significant improvement in all variables (p<0.05), while the general neck exercise group improved only in the neck disability index score. The differences between the two groups revealed further improvement in the scapular correction exercise group compared to the general neck exercise group (p<0.05). Conclusion: We found that five weeks of the scapular correction exercise to modify the position and movements of the scapula is clinically an important treatment tool for recovery from chronic mechanical neck pain symptoms and restoration of proper neck function.

• Physical Therapy Korea
• /
• v.26 no.3
• /
• pp.42-56
• /
• 2019

Background: Individuals with mechanical neck pain show biomechanical and neurophysiological changes, including cervical spine muscle weakness. As a result of deep muscle weakness, it causes stability disability and reduced upper thoracic spine mobility, which finally leads to functional movement restriction such as limited range of motion and dysfunction. Recent studies have shown that thoracic spine manipulation and mobilization could reduce symptoms of mechanical neck pain in patients. Objects: The purpose of this study was to investigate the effects of thoracic mobility exercise on cervicothoracic function, posture feature, and pain intensity in individuals with mechanical neck pain. Methods: The study subjects were 26 persons who were randomly assigned to the experimental (with thoracic mobility exercise) and control groups (without thoracic mobility exercise), with 13 subjects in each group. The cervicothoracic function (neck functional disability level and cervicothoracic range of motion), posture feature, and pain rating (using a quadrupled visual analogue scale [QVAS]) were measured before, after 3 weeks, and after 6 weeks. Results: Statistically significant group-by-time interactions were found with repeated analyses of variance for the Korean neck disability index (KNDI), all cervical range of motion (CROM), all thoracic range of motion (TROM), cranial rotation angle, sagittal shoulder posture (SSP), and QVAS (p<.05). All groups showed significant improvements from all times in all the evaluated methods. The KNDI, CROM, TROM of left rotation, and SSP in the experimental group showed significant improvements after 3 weeks, and the TROM of the right rotation and QVAS in the experimental group showed significant improvements after 6 weeks when compared with the control group. Conclusion: Thoracic mobility exercise during 6 weeks might be effective intervention to improve the functional level, posture feature, and QVAS pain rating for managing individuals with mechanical neck pain.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.1
• /
• pp.49-56
• /
• 2011

The neck injury occupies the most of injury that happened by the rear impact car accident. This study was analyzed about influence of the neck injury in low speed rear impact and car crash accident investigation. There is no neck injury in low speed side rear impact. On the other hand, there is initial neck injury symptom of 10 % but no long-term neck injury symptom in low speed offset rear impact. It appeared that the possibility of neck injury in low speed rear impact is low. For the more study about the neck injury, it should be evaluate the effects of the car body structure, frame structure and rear crash pattern.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.3
• /
• pp.224-229
• /
• 2009

An experimental study was conducted to investigate the effects of turtle neck syndrome, so called, on muscular fatigue and muscle activity. Six subjects (males) participated and performed the prolonged casual computer work in the study. EMG signals from six muscles of the dominant neck-back region were acquired and recorded for 10 seconds at the beginning and the end of three hours computer work. EMG was recorded from six muscles by using a computerized data recording and analysis system. Power spectrum function of EMG was calculated off-line by means of a signal processing software package. Power spectrum functions were smoothed with a moving average filter of 21 points and normalized with respect to the maximal value achieved during the trials. Muscle activity and median frequencies of Sternocleidomastoid(SCM) in turtle neck posture was approximately 51%, which were less than those in normal neck posture. SCM also showed the biggest decrease in median frequency. Results will provide the insight into the neck-back injury mechanism of turtle neck patients. Furthermore, they will be helpful in developing rehabilitation programs for restoring patients' neck-back functions.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.8
• /
• pp.212-219
• /
• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.