This article needs additional citations for verification. (September 2015) In common parlance, the core of the body is broadly considered to be the torso. Functional movements are highly dependent on this part of the body, and lack of core muscular development can result in a predisposition to injury.[1] The major muscles of the core reside in the area of the belly and the mid and lower back (not the shoulders), and peripherally include[clarification needed] the hips, the shoulders and the neck.
Major muscles included are the pelvic floor muscles, transversus abdominis, multifidus, internal and external obliques, rectus abdominis, erector spinae (sacrospinalis) especially the longissimus thoracis, and the diaphragm. The lumbar muscles, quadratus Lumborum (deep portion), deep rotators, as well as cervical muscles, rectus capitus anterior and lateralis, longus coli may also be considered members of the core group.[2] Minor core muscles include the latissimus dorsi, gluteus maximus, and trapezius.
The core is used to stabilize the thorax and the pelvis during dynamic movement and it also provides internal pressure to expel substances (vomit, feces, carbon-laden air, etc.).
Continence is the ability to withhold bowel movements, and urinary stress incontinence (the lack of bladder control due to pelvic floor dysfunction) can result from weak core musculature.
Core muscles, specifically the transversus abdominis, are used during labor and delivery.
Core muscles are also involved in the Valsalva maneuver, where the thorax tightens while the breath is held to assist, often involuntarily, in activities such as lifting, pushing, excretion and birthing.
The core is traditionally assumed to originate most full-body functional movement, including most sports. In addition, the core determines to a large part a person's posture. In all, the human anatomy is built to take force upon the bones and direct autonomic force, through various joints, in the desired direction. The core muscles align the spine, ribs, and pelvis of a person to resist a specific force, whether static or dynamic. [3] Static core functionality is the ability of one's core to align the skeleton to resist a force that does not change.
Example of static core functionFrom Army FM 3-22.9 page 4-16 An example of static core function is firing a rifle in the prone position. To maintain accuracy, the shooter must be able to transfer their body weight and the weight of the rifle into the earth. Any attempt of the shooter to create a dynamic motion of the sights (muscle the sights onto the target vs. allowing the posture to aim) will result in a jerky posture where the sights do not sit still on the target. For the shooter to maintain accuracy, the muscles cannot exert force on the rifle, and the skeleton must be aligned to set the rifle (and therefore the sights) onto the target. The core, while resting on the ground and relatively far away from the rifle, is nevertheless aligning the spine and pelvis to which the shoulder and arms and neck are connected. For these peripheral elements to remain static, and not move unnecessarily, the spine, pelvis, and rib cage must be aligned towards this end. Thus the core muscles provide support of the axial skeleton (skull, spine, and tailbone) in an alignment where the upper body can provide a steady, solid base for the rifle to remain motionless.
Dynamic core functionThe nature of dynamic movement must take into account our skeletal structure (as a lever) in addition to the force of external resistance, and consequently incorporates a vastly different complex of muscles and joints versus a static position. Because of this functional design, during dynamic movement there is more dependence on core musculature than just skeletal rigidity as in a static situation. This is because the purpose of the movement is not to resist a static, unchanging resistance, but to resist a force that changes its plane of motion. By incorporating movement, the bones of the body must absorb the resistance in a fluid manner, and thus tendons, ligaments, muscles, and innervation take on different responsibilities. These responsibilities include postural reactions to changes in speed (quickness of a contraction), motion (reaction time of a contraction), and power (amount of resistance resisted in a period of time). Example of dynamic core functionAn example of this is walking on a slope. The body must resist gravity while moving in a direction, and balancing itself on uneven ground. This forces the body to align the bones in a way that balances the body while at the same time achieving momentum through pushing against the ground in the opposite direction of the desired movement. Initially, it may seem that the legs are the prime movers of this action, but without balance, the legs will only cause the person to fall over. Therefore, the prime mover of walking is achieving core stability, and then the legs move this stable core by using the leg muscles.
ALL > Technology Nowadays, we see many home appliance giants rushing to launch cordless stick vacuum cleaners. This appliance is loved by many users as they are light in weight for even a child to steer, but yet boast strong suction power. The birth of cordless vacuums was possible in large part due to Li-ion batteries. Lightweight, high energy density Li-ion batteries with high capacity and efficiency than other batteries are widely applied in diverse areas ranging from small appliances and IT devices to power tools, energy storage systems and electric vehicles. Let's look into Li-ion batteries inside out today.
Samsung SDI’s Li-ion Batteries Four Components of Li-ion Battery – Cathode, Anode, Electrolyte, Li-ion batteries consist of largely four main components: cathode, anode, electrolyte, and separator.
The Four Components of Li-ion Battery ▶“Cathode” determines the capacity and voltage of a Li-ion battery A Lithium-ion battery generates electricity through chemical reactions of lithium. This is why, of course, lithium is inserted into the battery and that space for lithium is called “cathode”. However, since lithium is unstable in the element form, the combination of lithium and oxygen, lithium oxide is used for cathode. The material that intervenes the electrode reaction of the actual battery just like lithium oxide is called ”active material”. In other words, in the cathode of a Li-ion battery, lithium oxide is used as an active material.
If you take a closer look at the cathode, you willl find a thin aluminum foil used to hold the frame of the cathode coated with a compound made up of active material, conductive additive and binder. The active material contains lithium ions, the conductive additive is added to increase conductivity; and the binder acts as an adhesive which helps the active material and the conductive additive to settle well on the aluminum substrate. Cathode plays an important role in determining the characteristics of the battery as the battery’s capacity and voltage are determined by active material type used for cathode. The higher amount of lithium, bigger the capacity; and the bigger potential difference between cathode and anode, higher the voltage. The potential difference is small for anode depending on their type but for cathode, the potential difference is relatively high in general. As such, the cathode plays a significant role in determining the voltage of the battery. ▶ ”Anode” sends electrons through a wire Just like the cathode, the anode substrate is also coated with active material. The anode’s active material performs the role of enabling electric current to flow through the external circuit while allowing reversible absorption/emission of lithium ions released from the cathode. When the battery is being charged, lithium ions are stored in the anode and not the cathode. At this point, when the conducting wire connects the cathode to the anode (discharge state), lithium ions naturally flow back to the cathode through the electrolyte, and the electrons (e-) separated from lithium ions move along the wire generating electricity. For anode graphite which has a stable structure is used, and the anode substrate is coated with active material, conductive additive and a binder. Thanks to graphite’s optimal qualities such as structural stability, low electrochemical reactivity, conditions for storing much lithium ions and price, the material is considered suitable to be used for anode. ▶ “Electrolyte” allows the movement of ions only When explaining about cathode and anode, it was mentioned that lithium ions move through the electrolyte and electrons move through the wire. This is the key in enabling the use of electricity in a battery. If ions flow through the electrolyte, not only can’t we use electricity but safety will be jeopardized. Electrolyte is the component which plays this important role. It serves as the medium that enables the movement of only lithium ions between the cathode and anode. For the electrolyte, materials with high ionic conductivity are mainly used so that lithium ions move back and forth easily.
The electrolyte is composed of salts, solvents and additives. The salts are the passage for lithium ions to move, the solvents are organic liquids used to dissolve the salts, and the additives are added in small amounts for specific purposes. Electrolyte created in this way only allows ions to move to the electrodes and doesn’t let electrons to pass. In addition, the movement speed of lithium ions depends on the electrolyte type. Thus, only the electrolytes that meet stringent conditions can be used. ▶ ”Separator”, the absolute barrier between cathode and anode While the cathode and anode determine the basic performance of a battery, electrolyte and separator determine the safety of a battery. The separator functions as a physical barrier keeping cathode and anode apart. It prevents the direct flow of electrons and carefully lets only the ions pass through the internal microscopic hole. Therefore, it must satisfy all the physical and electrochemical conditions. Commercialized separators we have today are synthetic resin such as polyethylene (PE) and polypropylene (PP). So far, we have looked at the four main components which determine the performance of Li-ion batteries. Currently, Samsung SDI is strengthening R&D of new materials for the enhancement of battery performance while ceaselessly continuing its efforts to improve the performance of existing materials and core technologies. Through high capacity/high efficiency Li-ion battery innovation, Samsung SDI seeks to take the lead in the future battery industry which will enrich the lives of human beings all across the world. |
What are the four components of core?
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