Maximum Lifting Research Articles

Optimization of crane setup location and servicing schedule for urgent material requests with non-homogeneous and non-fixed material supply

Abstract Reducing hook movement distances could decrease crane operation times to deliver heavyweight materials in construction sites. Conventional scheduling methods include first-in-first-serve (FIFS), shortest-job-first (SJF), nearest-neighbor-first (NNF), and Traveling salesman problem (TSP). A new optimization model to optimize crane setup location, hook movement sequences and servicing schedules serving all supply and demand locations is proposed. Proposed model is able to model homogeneous and non-homogeneous material supply. Initial hook location can be given as input for optimization. Fixed material supply and demand location pairs are relaxed as model variables. Maximum crane lifting capacity is considered and multiple hook movement trips between material supply and demand locations are modeled if requested material weights exceed this maximum crane lifting capacity. Users may place “urgent” material demand requests and the proposed optimization model can optimize a servicing sequence to prioritize all urgent requests. The problem is formulated as a Binary-Mixed-Integer-Linear-Program (BMILP) which is solved by standard branch-and-bound techniques. Significant reduction in total operation time is achieved while comparing to other conventional scheduling strategies.

Decision-Making Data: Expectations for Reproducibility of Lifting on Separate Days.

Purpose:The purpose of this study was to explore the difference in maximal lifting capability between 2 modes of lifting (traditional crate and XRTS Lever Arm) over multiple days. The differences in absolute strength values were compared with existing criteria for sincere effort during distraction-based lifting. In addition, rate of perceived exertion (RPE) is presented for the 2 modes of lifting on each day.Primary Practice Setting:Workers' compensation.Methodology and Sample:Forty-four subjects between the ages of 20 and 44 years participated in this study. Investigators established 1 repetition maximum (RM) for each subject performing the crate lift. Subjects were randomly assigned 5 weights ranging from 10% to 100% of their determined 1RM and asked to give their rating of perceived exertion after each lift. The same procedure was repeated 2–5 days later using the XRTS Lever Arm. Paired t tests and Spearman's correlation coefficient were used for data analysis. Alpha was set at less than .05.Results:There was a statistically significant difference (p < .04) between maximal lift values for the 2 lifting modes. The percent difference between the modes of lifting was 10.5% ± 6.4%. In addition, there was a positive correlation between the RPE on the 2 modes of lifting (p = .87).Implications for Case Management Practice:A functional capacity evaluation (FCE) is typically ordered after the completion of physical rehabilitation and before releasing a patient to full or modified duty. In addition to assessing the ability to function within normal job demands, an assessment of effort by the participant typically takes place during an FCE. Case managers and physicians are presented with information, allowing them to make comparisons between functional lifting abilities displayed during treatment sessions and the FCE. These comparisons may often take place with the subpoena of medical records and may be discussed during the deposition or trial process. If an FCE takes place at a different facility than the physical therapy or work conditioning treatment, 2 different modes of lifting may take place based on the equipment within each facility. The results of this study indicate that the 2 modes of lifting on separate days meet established criteria for lift comparison testing during FCEs.

The Flow Visualization CFD Studies of the Fuselage and Rolled-up Vortex Effects of the Chengdu J-10-like Fighter Canard

Fighter aircrafts with high maneuverability and swiftness are due to fuselage effects, caused by canard-fuselage-main wing configuration. Even though the flows around fighters are highly complex, mostly they create rolled-up vortices capable to delay stalls and increase maximum lifts (Calderon, Wang &amp; Gursul, 2012; Mitchell &amp; Delery, 2001; Boelens, 2012; Chen, Liu, Guo &amp; Qu, 2015). The vortex dynamics analysis method employment is introduced, in this case we focus only on the fighter canard. It characterizes the vortex core, develops the pitching moment &amp; main wing total lift, and exploits the vortex centre visualization, the strength, negative surface pressure and its trajectory.This paper explains the influence of the fighter fuselage, it generates rolled-up vortex effects, causes the flow deflected by the fighter fuselage head, strengthen the vortex centre to become vortex core. Above the aircraft head, due to the curved contour head effect, the second vortex centers are developed makes the vortex center above the head more dynamic. Comparing with fighter without fuselage, the flow property changes, for Chengdu J-10-like model with fuselage, are concentrated at the canard leading edge, where the negative pressures are stronger, since the maximum axial velocities of the vortex centre are higher, and give more distinctive vortex breakdown locations.

Beta-Alanine Does Not Enhance the Effects of Resistance Training in Older Adults

ABSTRACTTo investigate the potential of beta-alanine to increase muscular endurance of elder individuals in specific resistance-training protocols, we randomly assigned 27 participants (60–82 years of age) to a 12-week double-blind intervention using 3.2 g/day beta-alanine or placebo with or without resistance training to determine the effects on anthropometrics, muscular performance, and activities of daily living (ADL). The endurance-based resistance-training program (ERT) was given three times per week and included two sets of 15–25 repetitions on 11 computerized pneumatic machines (alternating upper and lower body) at an intensity of 50% of maximum lifting weight (1RM). Mixed design analysis of variance (ANOVA) revealed no significant group × time interactions (p > .05) for any anthropometric or strength measures except 1RM leg press (p = .010). A post hoc analysis revealed significant improvements in 1RM leg press for both the resistance-training groups (p < .001) but no significant between-group difference attributable to beta-alanine. For the 20-repetition chest and leg press tests, no main effects of beta-alanine or group × time interactions for the exercise versus control groups were observed. Pairwise comparisons, however, did reveal significant improvements in peak and average power for both tests and fatigue index for the chest press in resistance-training groups. Although beta-alanine had no effect on any measures, the ERT program did positively affect three performance variables: 1RM, mechanical power, and fatigue patterns during muscular endurance testing. Future research should examine beta-alanine with different dosages and training programs to expand upon our findings using endurance-based resistance training.

Design of standard operating procedure (SOP) based at ergonomic working attitude through musculoskeletal disorders (Msd’s) complaints

PT PJC is a company synthetic resin. Synthetic resin is that produced by PT PJC is sold to the market in three types of packing, one of then is the drum packing type that weigh 208 kg. One of the activities that use the manual handling product (manual material handling) is the activity of filling, the drum-packed product will be transfered with drum packaging to the finishing goods area which done by the man force. Manual material handling concept has several advantages, one of which is easy to do by humans. However, manual handling material handling becomes an issue if the material load exceeds the maximum lifting of the worker because of the potential risk of injury to the human body, especially if it is carried out simultaneously for a relatively long period of time. One of the risks of human injury that can be experienced is Musculoskeletal Disorders (MSDs). This research will investigate the musculoskeletal complaints on Filling workers which will form the basic of the ergonomically-based Standard Operating Procedure (SOP) design basic. Data is taken by a Nordic Body Map (NBM) questionnaire. The result shows that most of the dominant body pain felt by the worker as the impact of previous day’s work was the complaints of pain on the left and right wrists, left and right palms, left and right knees, left and right calves, left and right ankles, while the pains felt by the workers after the activity are pain in the back, waist, left and right elbow, left and right thighs, left and right calvs, left and right ankles. The pain work will disappear after the night rest, but there is no guarantee that the worker’s body will be fit in the morning, because of the remnants of body pain that have not been fully fit, thus affecting the readiness of physical conditions at work in the morning. These body pain can be reduced by designing the right standard operating procedure (SOP) based on an ergonomic work attitude. Musculoskeletal pain before the activity were 39.3 ± 10.6 and after activity was 76.5 ± 14.9 or an increase in musculoskeletal pain of 94.66%.

Real-time simulation model for dynamic analysis of three-wheel counterbalance forklift

Modern multibody simulation techniques enable the explicit description of complex mechanical systems such as mobile and industrial machinery into relevant equations of motion. The subsequent solution of the equations of motion can lead to simulation in real-time. Presently, real-time simulation models based on multibody dynamics can account for a large number of rigid and flexible bodies as well as contact descriptions. It enables the inclusion of physical phenomena and user feelings associated with multibody systems in the real-time simulation. These specifications can be used in a number of product processes including user training and product development. The present study applies real-time multibody simulation to a three-wheel, two-ton counterbalance forklift. The forklift simulation model includes rigid bodies, joints, a contact model, friction forces, power transmission, and a steering mechanism. The study reports aspects associated with forklift performance such as speed, speed reduction around a curved path, mast wobbling, maximum lifting capacity, and vibrations during the lift. The simulation model is verified by comparing the speed, acceleration, mast lift and tilt speeds with the measurements of a reference forklift.

Real-time simulation model for dynamic analysis of three-wheel counterbalance forklift

Modern multibody simulation techniques enable the explicit description of complex mechanical systems such as mobile and industrial machinery into relevant equations of motion. The subsequent solution of the equations of motion can lead to simulation in real-time. Presently, real-time simulation models based on multibody dynamics can account for a large number of rigid and flexible bodies as well as contact descriptions. It enables the inclusion of physical phenomena and user feelings associated with multibody systems in the real-time simulation. These specifications can be used in a number of product processes including user training and product development. The present study applies real-time multibody simulation to a three-wheel, two-ton counterbalance forklift. The forklift simulation model includes rigid bodies, joints, a contact model, friction forces, power transmission, and a steering mechanism. The study reports aspects associated with forklift performance such as speed, speed reduction around a curved path, mast wobbling, maximum lifting capacity, and vibrations during the lift. The simulation model is verified by comparing the speed, acceleration, mast lift and tilt speeds with the measurements of a reference forklift.

Caffeine, acute static stretching and maximum knee flexion strength.

Reductions in one-repetition maximum lifts (1RM) following static stretching can be attributed to enhanced neural inhibition, which can be reduced by using stimulants like caffeine. This study compared knee-flexion 1RM following either static stretching (SS) or no-stretching (NS), as well as after ingesting either caffeine (C) or placebo (P). Twenty-four participants (12 female, 12 male) performed four random counterbalanced knee flexion 1RM tests. A 1RM test was performed for each condition at the same time of day with ~48 hours separating each test. Static stretching consisted of 5 exercises with the 1RM being performed immediately following the stretching. Caffeine dose was 6 mg/kg body weight, and the placebo was methylcellulose (520 mg). Both doses were administered as pills 60 minutes before the SS or NS procedures. Two-way repeated measures ANOVA showed a significant main effect for NS vs. SS (P<0.001, ηG2=0.23). The main effect for C vs. P, and the interaction between C vs. P and NS vs. SS were not statistically different. Average 1RMs were: CNS = 512±242 N, CSS = 474±241 N, PNS = 498±247 N, and PSS = 460±247 N. It is concluded that static stretching induced strength decrements are not removed by using stimulants at doses allowed by sport governing organizations.

Optimal Specifications for the Advanced Pedestrian Legform Impactor.

This study addresses the virtual optimization of the technical specifications for a recently developed Advanced Pedestrian Legform Impactor (aPLI). The aPLI incorporates a number of enhancements for improved lower limb injury predictability with respect to its predecessor, the FlexPLI. It also incorporates an attached Simplified Upper Body Part (SUBP) that enables the impactor's applicability to evaluate pedestrian's lower limb injury risk also with high-bumper cars. The response surface methodology was applied to optimize both the aPLI's lower limb and SUBP specifications, while imposing a total mass upper limit of 25 kg that complies with international standards for maximum weight lifting allowed for a single operator in the laboratory setting. All parameters were virtually optimized considering variable interaction, which proved critical to avoid misleading specifications. The results from this study can be used to construct physical aPLIs that are expected to be used in future car-to-pedestrian crash safety testing programs worldwide.

Hybrid BTT/STT missile autopilot design

PurposeTraditional skid-to-turn (STT) missile control mode is adopted mostly, but with the improvement of requirements for mobility and the emergence of new aerodynamic layout, a bank-to-turn (BTT) control mode gradually shows a greater advantage. However, the BTT missile also has certain defects, for example, when attacking against a maneuvering target and at the last section of guidance, the maximum lifting surface position of the missile needs to be adjusted frequently, thereby increasing the difficulty of control as well as introducing high-frequency noise.Design/methodology/approachBased on respective characteristics of the two control modes, this paper puts forward a hybrid autopilot design method based on nonlinear dynamic inversion. Firstly, the method converts overload instructions into corresponding angle instructions through the design of hybrid control guidance logic; secondly, based on the nonlinear dynamic inversion algorithm and combined with the fast-changing circuit/slowly changing circuit, a hybrid controller is designed; finally, combined with the missile mathematical model and actuator, it forms a autopilot design closed loop.FindingsThe simulation result shows that the non-linear dynamic inverse-based BTT/STT hybrid controller can input a track command well, normal overload and roll angle tracking performance have more advantages than the hybrid controller designed on the basis of classical control method in terms of overshooting and hysteretic characteristics.Originality/valueThe paper puts forward a new BTT/STT hybrid control method which has both the high mobile ability of the BTT missile and the precise control ability of the STT missile, which can adapt to the more complicated fighting environment. And, the method can effectively weaken the impact of the transformation of the control mode on the system.

Functional physical training improves women’s military occupational performance

The U.S. Armed Forces have recently approved full integration of women into combat roles. Physical fitness demands for executing Military Occupational Specialties (MOS) are substantial; thus lifting and load carriage capability improvements are desirable. ObjectivesTo determine if a specially-designed physical conditioning program could lessen the gap between the performance of male and female Soldiers in lifting and load carriage and thereby enable women to meet the requirements of most, if not all, Army MOSs. MethodsForty women participated in a 24-week physical training program, which included resistance training, long-distance running, backpacking, and specialized drills. Pre- and post-tests of occupational and physical performance measures were conducted before and after training. Repeated measures analysis of variance were used to determine statistically significant differences among the pre-, mid- and posttests. ResultsWomen increased maximal occupational lifting strength 12–20 kg, added 9–34 repetitions in lifting endurance, increased 0.23 m in jumping performance, added 46 repetitions in local muscular endurance, and decreased load carriage for time by 3.7–8.6 min. Women scored within 82–94% of untrained male scores for aerobic capacity and muscular endurance after training. ConclusionWomen’s ability to perform physically-demanding military occupational tasks was significantly improved following 6 months of concurrent training, with emphasis on load carriage and lifting. The percentage of women that qualified for current “heavy” and “very heavy” MOSs was initially 24%, but increased to 78% after training. A resistance training program of 6+ months can adequately prepare women for “heavy” to “very heavy” MOS’s.

Older females in the workforce – the effects of age on psychophysical estimates of maximum acceptable lifting loads

The number of older workers in the workforce is increasing substantially, and advanced age is associated with factors that could influence musculoskeletal injury risk and work capacity. This study’s goals were to test whether psychophysical estimates of maximum acceptable weight of lift (liftmax) differed between younger and older workers, and to examine potential explanatory factors. Twenty-four female workers (half 50 + years; half 20–32 years) self-adjusted a box’s mass to their perceived liftmax during four lifting tasks. Older workers’ liftmax values were significantly lower (by approximately 24%) than their younger counterparts. There were no age-related differences in resting heart rate, or peak joint angles and final heart rate during the lifting trials. However, the older group demonstrated lower grip strength (by 24%), and lower heart rate reserve during the trials (by 18%). These results question whether current maximum acceptable lifting weights based on psychophysical information are appropriately protective for female workers greater than 50 years of age.Practitioner Summary: This psychophysical study demonstrated that older female workers (aged 50–63 years) selected maximum acceptable lift masses that were (on average) 24% lower than younger workers (aged 20–32 years), which corresponded with lower grip strength and heart rate reserve. Current maximum acceptable lifting weights based on psychophysical information may not protect female workers greater than 50 years of age.

Systematic Review and Meta-Analysis of Predictors of Military Task Performance: Maximal Lift Capacity.

Hydren, JR, Borges, AS, and Sharp, MA. Systematic review and meta-analysis of predictors of military task performance: maximal lift capacity. J Strength Cond Res 31(4): 1142-1164, 2017-Physical performance tests (e.g., physical employment tests, return-to-duty tests) are commonly used to predict occupational task performance to assess the ability of individuals to do a job. The purpose of this systematic review was to identify predictive tests that correlate well with maximal lifting capacity in military personnel. Three databases were searched and experts in the field were contacted, resulting in the identification of 9 reports confined to military personnel that presented correlations between predictor tests and job tasks that measured maximal lift capacity. These 9 studies used 9 variations of a maximal lift capacity test, which were pooled to evaluate comparisons. The predictive tests were categorized into 10 fitness domains, which in ranked order were as follows: body mass and composition, absolute aerobic capacity, dynamic strength, power, isometric strength, strength-endurance, speed, isokinetic strength, flexibility, and age. Limitations of these data include a restricted age range (95% confidence interval [95% CI], 20-35; no correlations to maximal lift capacity) and the limited number of comparisons available within the cited studies. Weighted mean correlations ((Equation is included in full-text article.)) and 95% CI were calculated for each test. Lean body mass (kg) was the strongest overall predictor ((Equation is included in full-text article.); 95% CI, 0.697-0.966). Tests of dynamic strength had stronger correlations than strength endurance ((Equation is included in full-text article.), 95% CI, 0.69-0.89 vs. (Equation is included in full-text article.), 95% CI, 0.21-0.61). The following 6 domains of physical performance predictive tests had pooled correlations of 0.40 or greater for combined-sex samples: dynamic strength, power, isometric strength, strength endurance, speed, and isokinetic strength. Anthropometric measures explain 24-54% of maximal lift capacity variance, and lean body mass alone accounts for ∼69%. This review provides summarized information to assist in the selection of predictive tests for maximal lifting capacity in military personnel.

Thermo-sensitive isopentane aerification for mucosal lift during endoscopic resection in animal models (with video)

Mucosal lift is critical for successful endoscopic treatment. Normal saline (NS) solution is widely used as the submucosal filler, but its short persistency restricts clinical endoscopic submucosal dissection (ESD). In this study, thermo-sensitive isopentane was introduced for submucosal injection. With a boiling point at 27.8°C, liquid isopentane can be easily applied, and gasification inflation can provide great support for submucosal lifting at body temperature. The feasibility and efficiency of isopentane were evaluated in this study. Porcine stomachs were used for invitro evaluation. A 37°C water bath was used to mimic body temperature. Compared with NS, isopentane was studied for its lifting performance, including injection dosage, persistence of lifting strength, and efficacy for assisting submucosal dissection. The changes in submucosal tissue were also compared. For invivo evaluation, rats were used to further compare the differences between isopentane and NS, including lifting efficacy, pathologic effect, and safety. Compared with NS, the maximum lifting height was achieved with less isopentane (2% NS volume). Longer persistency and faster operation for submucosal dissection were also recorded for isopentane during the invitro study. Aerification resulted in vacuolization of submucosal connective tissue, which facilitates EMR and postoperative recovery. The same results were confirmed in the rat model. With the same dosage, isopentane produced better mucosal elevation and larger range than NS. According to the histologic examination, no tissue injury was observed with isopentane application. As a submucosal injection agent, the feasibility, efficacy, and safety of isopentane has been demonstrated. Thermo-sensitive aerification may be a promising approach to facilitate ESD.

Design and Development of Portable Crane in Production Workshop: Case Study in BISHOPTU AUTOMOTIVE INDUSTRY, Ethiopia

This portable crane uses a hydraulic system to lift a heavy loads applying only small force. The main advantage of the project is having detail design of the mechanism in the production workshop of BISHOFTU AUTOMOTIVE INDUSTRY; Ethiopia is that it is portable, moveable, and easy for operation. In this project we designed and produced a portable crane which can lift a heavy load with a maximum capacity of 3 ton. The crane has two loaded side bars to make the base and two links (i.e. Vertical column and boom) connected each other by using pin joint. The Vertical column is secured on the cross bar that is welded to the side bars making the base using bolt connection. There are also other bars for supporting purpose which are connected to the basic link (vertical column) using bolt connection. The crane uses four wheels, of which two of them in the front are connected to the base using permanent joint and the rear wheel is connected to the base using roller. Since the crane operates hydraulically there is piston cylinder device which is connected to the vertical column and boom for lifting up and down the objects. The maximum carrying capacity 3 ton, and maximum lifting height is estimated as greater than greater than 2.96m from the ground run by using 3KW electric motor rotating 2830/3620 rpm.

Asymmetry costs: effects of wing damage on hovering flight performance in the hawkmoth Manduca sexta.

Flight performance is fundamental to the fitness of flying organisms. Whilst airborne, flying organisms face unavoidable wing wear and wing area loss. Many studies have tried to quantify the consequences of wing area loss to flight performance with varied results, suggesting that not all types of damage are equal and different species may have different means to compensate for some forms of wing damage with little to no cost. Here, we investigated the cost of control during hovering flight with damaged wings, specifically wings with asymmetric and symmetric reductions in area, by measuring maximum load lifting capacity and the metabolic power of hovering flight in hawkmoths (Manduca sexta). We found that while asymmetric and symmetric reductions are both costly in terms of maximum load lifting and hovering efficiency, asymmetric reductions are approximately twice as costly in terms of wing area lost. The moths also did not modulate flapping frequency and amplitude as predicted by a hovering flight model, suggesting that the ability to do so, possibly tied to asynchronous versus synchronous flight muscles, underlies the varied responses found in different wing clipping experiments.

Comparing the effect of resistance, aerobic, and concurrent exercise program on the level of resistin and high reactive protein C of overweight and obese women

History and Objective: Obesity is one of the health risks factors, and aerobic exercise is one of the means to prevent and control obesity. The research was designed to compare methods of resistance, aerobic, and concurrent exercises on resistin and C-reactive protein (CRP) serum level of overweight and obese women. Research Methodology: In this semi-experimental research, 36 voluntary overweight or obese women were randomly assigned into three groups (n = 12) of aerobic, resistance, and concurrent exercise programs. The training included 8 weeks of exercise performed with 55%–75% of 1-repetition maximum weight lifting. The aerobic exercise was performed at 55%–75% of maximum oxygen consumption and concurrent training included both programs for 3 days/week. The resistin and CRP serum level of the participant was measured 48 h before the start and again 48 h after the termination of the exercise protocol. The statistical analysis was performed on data using SPSS 22.0 (Chicago, USA). One-way analysis of variance and paired t-test was employed to test the hypothesis at significance level set to 0.05. Results: The result indicated that exercise program significantly decreased CRP level of blood serum (P 0.05). Discussion: Aerobic exercise regardless of types has a beneficiary effect on CPR, but resistin level needs different types of exercise to change in overweight and obese women. Conclusion: Some aerobic exercises are beneficiary for overweight and obese women health.

EMG Processing Based Measures of Fatigue Assessment during Manual Lifting.

Manual lifting is one of the common practices used in the industries to transport or move objects to a desired place. Nowadays, even though mechanized equipment is widely available, manual lifting is still considered as an essential way to perform material handling task. Improper lifting strategies may contribute to musculoskeletal disorders (MSDs), where overexertion contributes as the highest factor. To overcome this problem, electromyography (EMG) signal is used to monitor the workers' muscle condition and to find maximum lifting load, lifting height and number of repetitions that the workers are able to handle before experiencing fatigue to avoid overexertion. Past researchers have introduced several EMG processing techniques and different EMG features that represent fatigue indices in time, frequency, and time-frequency domain. The impact of EMG processing based measures in fatigue assessment during manual lifting are reviewed in this paper. It is believed that this paper will greatly benefit researchers who need a bird's eye view of the biosignal processing which are currently available, thus determining the best possible techniques for lifting applications.

The effect of craniokinesis on the middle ear of domestic chickens (Gallus gallus domesticus).

The avian middle ear differs from that of mammalians and contains a tympanic membrane, one ossicle (bony columella and cartilaginous extra-columella), some ligaments and one muscle. The rim of the eardrum (closing the middle ear cavity) is connected to the neurocranium and, by means of a broad ligament, to the otic process of the quadrate. Due to the limited number of components in the avian middle ear, the possibilities of attenuating the conduction of sound seem to be limited to activity of the stapedius muscle. We investigate to what extent craniokinesis may impact the components of the middle ear because of the connection of the eardrum to the movable quadrate. The quadrate is a part of the beak suspension and plays an important role in craniokinesis. Micro-computed tomography was used to visualize morphology and the effect of craniokinesis on the middle ear in the domestic chicken (Gallus gallus domesticus). Both hens and roosters are considered because of their difference in vocalization capacity. It is hypothesized that effects, if present, of craniokinesis on the middle ear will be greater in roosters because of their louder vocalization. Maximal lower jaw depression was comparable for hens and roosters (respectively 34.1±2.6° and 32.7±2.5°). There is no overlap in ranges of maximal upper jaw elevation between the sexes (respectively 12.7±2.5° and 18.5±3.8°). Frontal rotation about the transversal quadrato-squamosal, and inward rotation about the squamosal-mandibular axes of the quadrate were both considered to be greater in roosters (respectively 15.4±2.8° and 11.1±2.5°). These quadrate rotations did not affect the columellar position or orientation. In hens, an influence of the quadrate movements on the shape of the eardrum could not be detected either; however, craniokinesis caused slight stretching of the eardrum towards the caudal rim of the otic process of the quadrate. In roosters, an inward displacement of the conical tip of the tympanic membrane of 0.378±0.21mm, as a result of craniokinesis, was observed. This is linked to a flattening and slackening of the eardrum. These changes most likely go along with a deformation of the extra-columella. Generally, in birds, larger beak opening is related to the intensity of vocalization. The coupling between larger maximal upper jaw lifting in roosters and the slackening of the eardrum suggest the presence of a passive sound attenuation mechanism during self-vocalization.

OPINIONS ABOUT ALLOTTING STRAINS ON THE LAYERS OF A LAMINATED MONOLITH COMPOSITE

A previous paper stated the method of determination of the neutral surface of a composite monolithic, laminate composite, organizing some of the component layers, go to the method of distribution of tasks developed in one given case. This regard illustrates several possible options of which results can enable a proper assessment of the maximum strains and alignment layers, ensuring a maximum lifting capacity. The study can be developed to optimize the organization of layers, depending on the practical purpose of using the composite structure (mechanical, thermal and / or sound).