Initial Seat Research Articles

Research on Automotive Seat Heating Strategy Based on Objective Thermal Comfort Evaluation

Abstract Seat heating is an essential means to improve cabin occupant thermal comfort. How to set a reasonable seat heating strategy is very important to improve occupant thermal comfort and reduce vehicle energy consumption. Based on objective thermal comfort evaluation criteria, this paper analyzes three strategies: fixed heating power, fixed seat surface temperature, and intermittent seat heating. It explores the occupant thermal comfort characteristics under different strategies. It is found that the optimum heating power or optimum seat surface temperature to maintain occupant thermal comfort varies with the initial seat temperature. Compared with the two strategies of fixed heating power and fixed seat surface temperature, the intermittent seat heating proposed in this paper can make the human body reach the optimal state of comfort in a shorter period, and the power consumption is less as the seat heating is opened for a longer time. This intermittent seat heating strategy not only adapts to different low-temperature environments outside but also provides sufficient safety guarantees while improving human thermal comfort. It can provide some references for the design of car seat heating and research on passenger cabin thermal comfort.

Effect of seat back angle on preferred seat pan inclination for the development of highly automated vehicles

Recent studies on occupants’ safety in reclined positions suggest that a more inclined seat pan could be needed to reduce the occurrence of submarining. This study aimed to investigate whether a more inclined seat pan would also be comfortable for occupants. Eighteen volunteers participated in the experiment. They were asked to self-select seat pan inclination for seat back angles from 20 to 60 degrees using a reconfigurable experimental seat from two initial seat pan angles (10 and 40 degrees from the horizontal). On average, preferred seat pan angle varied from 11.3(±2.1, standard deviation) to 29.9(±6.8), 12.5(±3.8) to 37.4(±3.7), and 12.8(±4.8) to 38.6(±2.7) degrees for seat pan angles of 20, 40, and 60 degrees respectively. The shear force analysis suggests that the seat pan inclination might be self-selected to reduce the forward shear, while a high inclination angle with a noticeable backward shear was also preferred. Practitioner summary: Preferred range of seat pan inclination for different seat back angles studied for the development of highly automated vehicles. The present work provides quantitative guidelines for specifying comfortable seating in a reclined position.

Social distancing in airplane seat assignments for passenger groups

We provide a mixed-integer programming model (MIP) to assign airplane passengers to seats while preserving two types of social distancing: the distance from the passengers’ seats to the aisle and the distance among groups of passengers who are not travelling together. The method assigns passengers travelling within a family group to seats near others of the same group. We present a heuristic algorithm to solve the proposed MIP. This algorithm is warm started with an initial seat assignment. Stochastic simulation experiments using the new method confirm that more passengers can be assigned safely to the seats when family groups are considered. For a certain load of passengers, as the percentage of family groups compared to singleton passengers increases, the model can practice social distancing among more passengers from different groups. The proposed model provides a superior seating assignment compared to an airline policy of blocking all middle-seats.

Dramatic invasion of the orbit by periocular cutaneous squamous cell carcinoma

The periocular skin is susceptible to numerous benign and malignant neoplasms. Malignant skin tumors of the periocular area are very particular; they can present differently, are rapidly aggressive and pose a real therapeutic challenge. Aggressive forms occur mostly in immunocompromised individuals. A complete destruction of the orbit is rare and the initial seat is most often the eyelid. We report the case of an immunocompetent 70-year-old patient with destruction of the entire orbital region including the eyeball secondary to the extension of squamous cell carcinoma of the internal canthus.

Hemorrhagic Breakdown of the Cerebral Bridge: A Report of 5 Observations at Lomé Teaching Hospital, Togo

Introduction: Intracerebral hemorrhage is a major public health problem in Africa. The care is well codified in developed nations but the medical outcome and the technical platform remains a thorny challenge in African countries. It is responsible for a heavy handicap and a high mortality. The corpus callosum is an anatomical structure that connects the two cerebral hemispheres and control neuropsychological behavior. The objective was to determine the epidemiological and clinical characteristics of hematomas located in the corpus callosum. Clinical presentation: The stuy was carried out in the neurlogical department of the big tertiary hospital of the country. The study had reported five cases of hematoma of the corpus callosum. That has represented 0.3% of hemorrhagic strokes in the service. The average age was 33.4 years old with four females. Clinical symptoms in the acute phase were dominated by speech disorders, intracranial hypertension and meningeal signs. In the subacute phase, all patients had neuropsychological symptoms. These disorders included aphasia, left tactile anomia, ideomotor and diagonostic apraxia, and mood and behavior disorders in two-third of cases. The brain scan was performed with an average delay of 6 days. In the cerebral scan, the posterior part of the corpus callosum was the initial seat of the hematomas observed in all cases. Cerebrovascular risk factors were high blood pressure in all cases and alcoholism in two cases. The factor of poor prognosis was the association with meningeal contamination. The evolution was favorable in all five cases. Conclusion: This work brings out that hematoma of the corpus callosum is rare but still a serious disease with a misleading semiology dominated by neuropsychological disorders. The early management is the best practice to preserve functional autonomy.

Modeling passengers boarding in aircraft using cellular automata

Aircraft are profitable to their owners as long as they are in the air transporting passengers to their destinations; therefore it is vital to minimize as much as possible their preparation time on the ground. In this paper we simulate different boarding strategies with the help of a model based on cellular automata parallel computational tool, attempting to find the most efficient way to deliver each passenger to her or his assigned seat. Two seat arrangements are used, a small one based on Airbus A320 U+002F Boeing 737 and a larger one based on Airbus A380 U+002F Boeing 777-300. A wide variety of parameters, including time delay for luggage storing, the frequency by which the passengers enter the plane, different walking speeds of passengers depending on sex, age and height, and the possibility of walking past their seat, are simulated in order to achieve realistic results, as well as monitor their effects on boarding time. The simulation results indicate that the boarding time can be significantly reduced by the simple grouping and prioritizing of passengers. In accordance with previous papers and the examined strategies, the outside-in and reverse pyramid boarding methods outperform all the others for both the small and large airplane seat layout. In the latter, the examined strategies are introduced for first time in an analogous way to the initial small seat arrangement of Airbus A320 U+002F Boeing 737 aircraft family. Moreover, since in real world scenarios, the compliance of all the passengers to the suggested group division and boarding strategy cannot be guaranteed, further simulations were conducted. It is clear that as the number of passengers disregarding the priority of the boarding groups increases, the time needed for the boarding to complete tends towards that of the random boarding strategy, thus minimizing the possible advantages gained by the proposed boarding strategies.

Effect of different hand positions on trunk and shoulder kinematics and reaction forces in sitting pivot transfer.

[Purpose] The purpose of this study was to compare the changes in trunk and shoulder angles, and reaction forces under the two hands elicited by different hand base of support positions during sitting pivot transfer. [Subjects and Methods] Eighteen unimpaired subjects performed independent sitting pivot transfer. Subjects performed sitting pivot transfer between an initial seat to a target seat by only using their hands positioned at the same height as and lower than the seat position. Trunk and shoulder kinematics, and reaction forces on the trailing and leading hands were calculated. Mean peak joint angles and forces were compared between the hand positions using the pared t-test for the lift phase of the transfer. [Results] There were significant increases in the trunk angles of forward and lateral flexion, even though rotation decreased while transferring in the lower hand position. Increased shoulder flexion, anterior/posterior forces and reduced lateral forces were also shown. [Conclusion] Placing the hands of the supporting arms lower than the seat position during sitting pivot transfer was identified as having biomechanical advantages. Therefore, the lower hand position can be recommended as an effective and safe method for sitting pivot transfer by patients with spinal cord injury and can be utilized as a reference data for considering the appropriate height of aids for a wheelchair.

Evaluation of the Head Kinematics of the Q3 Model and a Modified Q3 Model by Means of Crash Reconstruction

Objective: One objective of this study is to evaluate the head kinematics of the Q3 model. Another objective is to evaluate the effect on head kinematics of increased thoracic spine flexibility; more humanlike mass distribution; and more humanlike body geometry in the Q3 model. The evaluations were based on the head kinematics of children deduced from real crashes and on new data of mass distribution and updated body dimensions for 3-year-olds. Methods: The head kinematics of the Q3 model was evaluated by comparing the Q3 model's head displacement response with the deduced response of 3-year-old children in real crashes. To do so, data from crashes were collected. The data were used to develop the mathematical vehicle and restraint system models (MADYMO, TASS, the Netherlands). Three crashes involving 3-year-old children in frontal impacts were reconstructed. The models were run 35 times each (one model per crash), each time with a different setting to each of the variables for which the exact value was not known. Examples of those variables include crash pulse, initial dummy position, and initial seat belt position. Two versions of the Q3 model were used: one that correlated with the Q3 ATD and one that was modified regarding anthropometry and thoracic flexibility. The basis for the updated anthropometry was new data regarding characteristic dimensions and mass distribution collected at a Swedish hospital. Results: In the anthropometry study, 26 children were measured. The main differences between the average of the measured children and the Q3 model were found in the mass distribution of the torso and thighs: the Q3's pelvis was too heavy and the thorax, abdomen/lumbar spine, and thighs were too light. Another difference was identified in the buttock–knee length. Two of the 3 reconstructed crashes had confirmed head impacts. The Q3 model responded with head kinematics that reflected the deduced courses of events for the real children in one of 3 crashes (the one without head impact). The modified Q3 model reflected the real children in 2 of 3 crashes. Conclusions: In high-severity, straight frontal crashes, the Q3 model predicted non-head impact adequately. However, in oblique frontal crashes, the Q3 model did not sufficiently predict the head impacts. The modified Q3 model predicted the head impacts better than the Q3 model did. Greater flexibility of the thorax and redistributed mass made a positive difference regarding the head kinematics.

Measuring dynamic stability requirements during sitting pivot transfers using stabilizing and destabilizing forces in individuals with complete motor paraplegia

Dynamic stability requirements have never been quantified when long-term manual wheelchair users transfer themselves in a seated position from an initial surface to a target surface, a functional task commonly referred to as sitting pivot transfers (SPTs). Ten individuals with spinal cord injury (SCI), who rely on a manual wheelchair for mobility, underwent a comprehensive biomechanical SPT assessment. SPTs performed toward a target seat of same height (even) and a seat 10cm higher than the initial seat (uneven), repeated three times for each task, were assessed. A dynamic equilibrium model, continuously measuring the theoretical forces required to move the center of pressure to the limit of the base of support (destabilizing force) and to neutralize the kinetic energy and stop the displacement of the center of mass at the limit of the base of support (stabilizing force) at each instance during the performance of SPTs, was used to identify the phases of greatest instability during the SPT tasks. The greatest levels of instability were reached around the time the buttocks lost contact with the initial seat and around the time the buttocks landed on the target seat (pre- and post-lift transition phases). These transition periods, characterized by the lowest destabilizing force (424.7–487.1N) and the greatest stabilizing force (24.2–33.2N), confirmed the greatest level of instability. The height of the target seat had no significant effect (p=0.278–0.739) on dynamic postural stability requirements during the SPTs. During SPTs towards even and uneven target seats, the greatest postural instability occurs during the transition phases in individuals with complete motor thoracic SCI.

Electromyographic patterns of upper extremity muscles during sitting pivot transfers performed by individuals with spinal cord injury

Although substantial upper extremity (U/E) muscular efforts are required when individuals with spinal cord injury (SCI) perform sitting pivot transfers, little is known about the electromyographic (EMG) activation patterns of key shoulder and elbow muscles solicited during the performance of this functional task. The aims of this study were to examine the EMG activation patterns of U/E muscles in 10 males with SCI, and to compare them across sitting pivot transfers performed toward seats of different heights (low, same, high). EMG data from the biceps, triceps, deltoid, pectoralis major and latissimus dorsi were recorded bilaterally. Transfers were divided into pre-lift, lift, and post-lift phases. Each phase was time- and amplitude-normalized using a mean dynamic EMG approach. Similar EMG activation patterns were found across the different transfers for all muscles ( r mean = 0.942–0.991), whereas moderate to high inter-subject variability (CV: 20.9–70.6%) was reported for the different muscles and transfers. Peak EMG occurred earlier at the trailing U/E compared to the leading one, and was observed around seat-off for most of the muscles. When transfer to a high target seat was compared to transfer to one of the same height, significantly higher relative EMG values were observed at the biceps (mean: 1.64 vs. 1.00) of the leading U/E as well as the deltoid (mean: 1.20 vs. 1.00) and pectoralis major (mean: 1.20 vs. 1.00; peak: 2.27 vs. 1.79) of the trailing U/E. Transferring to a low target seat did not lead to lower muscular demand than transferring to one of the same height ( P > 0.05). These results indicate that coordinated and higher muscular efforts were generated at the trailing deltoid and pectoralis major when transferring to a high target seat compared to one of similar height. Higher muscular efforts were also developed at the leading biceps when transferring to a high target seat compared to a leveled one. Lowering the target seat with respect to the initial seat had no favorable effect on muscular demand.

Trunk and upper extremity kinematics during sitting pivot transfers performed by individuals with spinal cord injury

Although reaching an optimal level of independence during sitting pivot transfer is crucial for individuals with spinal cord injury, little is known regarding the kinematic requirements of this functional task. Ten males with spinal cord injury performed independent sitting pivot transfers between an initial seat and a target one placed at same (50 cm), lower (40 cm), and higher heights (60 cm) than the initial one, using their usual movement strategies. Three-dimensional trunk, shoulder, elbow and wrist kinematics were collected bilaterally during sitting pivot transfers. Each sitting pivot transfer was divided into three phases for analysis: pre-lift, lift-pivot and post-lift. Temporal parameters were also documented. Peak shoulder extension displacement and velocities were always higher at the leading shoulder compared to the trailing one (P<0.004), and almost coincided with peak trunk velocities early during the lift phase. With increasing target seat height, shoulder flexion (P<0.011) and elbow extension (P<0.013) displacements and velocities of the trailing upper extremity augmented and reached higher values at this upper extremity compared to the leading upper extremity, with one exception at the shoulder. Elbows generally remained flexed (min=28-56 degrees ) during the lift phase of all transfers whereas extreme wrist extension positions (max=84-88 degrees ) were documented across all transfers. Total durations of transfers (2.6-2.8s) and lift-pivot phases (1.0-1.3s) were not affected by target seat heights. Sitting pivot transfers are characterized by substantial angular displacements and velocities at the trunk and upper extremities. Some kinematic parameters documented during sitting pivot transfers may increase the risk of developing secondary musculoskeletal impairments in this population.

THE INFLUENCE OF SEAT POSITION ON LOWER EXTREMITY MECHANICS DURING RECUMBENT STEPPING

Recumbent stepping ergometers are effective for improving cardiovascular and muscular fitness, which are often goals of rehabilitation. Stationary cycling ergometers have traditionally filled this role. Seat position is normally an important variable that clinicians must consider relative to joint kinetics during cycling especially for individuals with lower extremity limitations. However, few data are available concerning recumbent steppers, seat position, and lower extremity mechanics. PURPOSE To evaluate the magnitude of hip and knee moments, knee reaction forces, and knee flexion angle during recumbent stepping. METHODS Twelve healthy males with no history of lower extremity injury participated (mean ±SD, age: 21.2 ±2.0 y; height: 1.77 ±0.05 m; mass: 76.3 ±11.5 kg). Subjects were videotaped with a pair of 60Hz cameras as they performed moderate (RPE=3, cadence=80 steps/min) exercise on a recumbent stepper. Four seat positions were used resulting in minimum knee flexion angles of 0° (full extension), 15°, 30°, and 45°. The right pedal of the stepper was fitted with a load cell to measure the forces and moments creates by the foot against the pedal. Video and force data were synchronized and combined with anthropometric data from each subject's right leg to perform an inverse dynamics analysis of the lower extremity. Peak flexion/extension moments for the hip and knee were extracted, as well as, anterior/posterior knee forces, proximal/distal knee forces, and maximum knee flexion angles. RESULTS Maximum knee flexion angle increased from the 0° initial seat position to the 45° initial seat position (p = .019). Hip and knee kinetics were not different across seat positions (p > .05). CONCLUSION Our results indicate that seat position does not influence lower extremity mechanics during recumbent stepping for healthy individuals exercising at moderate workloads. Contrary to rehabilitation performed on a stationary cycle, initial seat position on a recumbent stepper may not be an issue for clinicians when joint kinetics are the primary concern. Supported by NuStep, Inc. (UPN 01061905).

The stone synthronon and the frieze of fresco icons in the altar in the Church of the Ascension of Christ in Zica

The semi-circular exedra at the end of the altar apse, with a single or step-like bench and a cathedra in the centre, is among the important, focal points in the liturgical rites of the Orthodox Christian Church: the hierarchs dwells in the "upper place" several times during the Divine Liturgy. Here, in the act of enthronement, he receives the administration of his church. The synthronon is reserved for the co-administrants. The function of this part of the building soon began to influence the programme of the painted ornamentation. Among the mechanisms linking the exedra and the painting in the altar area, one can distinguish the translation of the symbolic base of the cathedra in the upper place and the synthronon in the programme and the adaptation of the ornaments to their liturgical and ritual application. The painting of the lowest zone of the apse in Zica, the initial seat of the autocephalous Serbian church, comprises both these principles. It is testimony of the mutual inter-relationship of the function of the space, and the symbolism and painting that was created from it...

HEREDITY IN EPILEPSY

There are still people who use congenital and as synonyms, and who speak of inherited (meaning congenital) syphilis, forgetting that the parent is merely the carrier of a foreign body, a spirochete, to the fetus, and that there is nothing genetic in the process. Many accept the appearance of a disease or abnormality in successive generations as absolute proof of heredity: it is not, as is shown in miner's phthisis, in which the exposure to the same environment is the cause, and not heredity. I shall use J. Arthur Thompson's definition of heredity. He says by inheritance we mean all the qualities or characters which have their initial seat, their physical basis, in the fertilized egg cell; the expression of this inheritance in development results in the organism. Thus, heredity is no entity, no force, no principle, but a convenient term for the genetic relation between successive generations, and