Friction
Orthodontic Appliance Design
Stainless Steel
Elastomers
Surface Properties
Orthodontic Brackets
Viscosity
Physical Phenomena
Materials Testing
Biomechanical Phenomena
Textiles
Physics
Dental Alloys
Stress, Mechanical
Saliva, Artificial
Weight-Bearing
Neuronal activity in somatosensory cortex of monkeys using a precision grip. III. Responses to altered friction perturbations. (1/387)
The purpose of this investigation was to examine the activity changes in single units of the somatosensory cortex in response to lubricating and adhesive coatings applied to a hand-held object. Three monkeys were trained to grasp an object between the thumb and index fingers and to lift and hold it stationary within a narrow position window for 1 s before release. Grip forces normal to the skin surface, load forces tangential to the skin surface, and the displacement of the object were measured on each trial. Adhesive (rosin) and lubricant (petroleum jelly) coatings were applied to the smooth metal surface of the object to alter the friction against the skin. In addition, neuronal activity evoked by force pulse-perturbations generating shear forces and slip on the skin were compared with the patterns of activity elicited by grasping and lifting the coated surfaces. Following changes in surface coatings, both monkeys modulated the rate at which grip forces normal to the skin surface and load forces tangential to the skin surface were applied during the lifting phase of the task. As a result, the ratio of the rates of change of the two forces was proportionately scaled to the surface coating properties with the more slippery surfaces, having higher ratios. This precise control of normal and tangential forces enabled the monkeys to generate adequate grip forces and prevent slip of the object. From a total of 386 single neurons recorded in the hand area of the somatosensory cortex, 92 were tested with at least 1 coating. Cell discharge changed significantly with changes in surface coating in 62 (67%) of these cells. Of these coating-related cells, 51 were tested with both an adhesive and lubricating coating, and 45 showed significant differences in activity between the untreated metal surface and either the lubricant or the adhesive coating. These cells were divided into three main groups on the basis of their response patterns. In the first group (group A), the peak discharge increased significantly when the grasped surface was covered with lubricant. These cells appeared to be selectively sensitive to slip of the object on the skin. The second group (group B) was less activated by the adhesive surface compared with either the untreated metal or the lubricated surface, and they responded mainly to variations in the force normal to the skin surface. These cells provide useful feedback for the control of grip force. The third group (group C) responded to both slips and to changes in forces tangential to the skin. Most of these cells responded with a biphasic pattern reflecting the bidirectional changes in load force as the object was first accelerated and then decelerated. One hundred sixty-eight of the 386 isolated neurons were tested with brief perturbations during the task. Of these, 147 (88%) responded to the perturbation with a significant change in activity. In most of the cells, the response to the perturbation was shorter than 100 ms with a mean latency of 44.1 +/- 16.3 (SD) ms. For each of the cell groups, the activity patterns triggered by the perturbations were consistent with the activity patterns generated during the grasping and lifting of the coated object. (+info)Influence of archwire and bracket dimensions on sliding mechanics: derivations and determinations of the critical contact angles for binding. (2/387)
There is every indication that classical friction controls sliding mechanics below some critical contact angle, theta c. Once that angle is exceeded, however, binding and notching phenomena increasingly restrict sliding mechanics. Using geometric archwire and bracket parameters, the theta c is calculated as the boundary between classical frictional behaviour and binding-related phenomena. What these equations predict is independent of practitioner or technique. From these derivations two dimensionless numbers are also identified as the bracket and the engagement index. The first shows how the width of a bracket compares to its Slot; the second indicates how completely the wire fills the Slot. When nominal wire and bracket dimensions are calculated for both standard Slots, the maximum theta c theoretically equals 3.7 degrees. Thus, knowledge of the archwire or bracket alone is insufficient; knowledge of the archwire-bracket combination is necessary for theta c to be calculated. Once calculated, sliding mechanics should be initiated only after the contact angle, theta, approaches the characteristic value of theta c for the particular archwire-bracket combination of choice--that is, when theta approximately theta c. (+info)The diving physiology of bottlenose dolphins (Tursiops truncatus). II. Biomechanics and changes in buoyancy at depth. (3/387)
During diving, marine mammals must balance the conservation of limited oxygen reserves with the metabolic costs of swimming exercise. As a result, energetically efficient modes of locomotion provide an advantage during periods of submergence and will presumably increase in importance as the animals perform progressively longer dives. To determine the effect of a limited oxygen supply on locomotor performance, we compared the kinematics and behavior of swimming and diving bottlenose dolphins. Adult bottlenose dolphins (Tursiops truncatus) were trained to swim horizontally near the water surface or submerged at 5 m and to dive to depths ranging from 12 to 112 m. Swimming kinematics (preferred swimming mode, stroke frequency and duration of glides) were monitored using submersible video cameras (Sony Hi-8) held by SCUBA divers or attached to a pack on the dorsal fin of the animal. Drag and buoyant forces were calculated from patterns of deceleration for horizontally swimming and vertically diving animals. The results showed that dolphins used a variety of swimming gaits that correlated with acceleration. The percentage of time spent gliding during the descent phase of dives increased with depth. Glide distances ranged from 7.1+/-1.9 m for 16 m dives to 43.6+/-7.0 m (means +/- s.e.m.) for 100 m dives. These gliding patterns were attributed to changes in buoyancy associated with lung compression at depth. By incorporating prolonged glide periods, the bottlenose dolphin realized a theoretical 10-21 % energetic savings in the cost of a 100 m dive in comparison with dives based on neutral buoyancy models. Thus, modifying locomotor patterns to account for physical changes with depth appears to be one mechanism that enables diving mammals with limited oxygen stores to extend the duration of a dive. (+info)Direct observation of one-dimensional diffusion and transcription by Escherichia coli RNA polymerase. (4/387)
The dynamics of nonspecific and specific Escherichia coli RNA polymerase (RNAP)-DNA complexes have been directly observed using scanning force microscopy operating in buffer. To this end, imaging conditions had to be found in which DNA molecules were adsorbed onto mica strongly enough to be imaged, but loosely enough to be able to diffuse on the surface. In sequential images of nonspecific complexes, RNAP was seen to slide along DNA, performing a one-dimensional random walk. Heparin, a substance known to disrupt nonspecific RNAP-DNA interactions, prevented sliding. These observations suggest that diffusion of RNAP along DNA constitutes a mechanism for accelerated promoter location. Sequential images of single, transcribing RNAP molecules were also investigated. Upon addition of 5 microM nucleoside triphosphates to stalled elongation complexes in the liquid chamber, RNAP molecules were seen to processively thread their template at rates of 1.5 nucleotide/s in a direction consistent with the promoter orientation. Transcription assays, performed with radiolabeled, mica-bound transcription complexes, confirmed this rate, which was about three times smaller than the rate of complexes in solution. This assay also showed that the pattern of pause sites and the termination site were affected by the surface. By using the Einstein-Sutherland friction-diffusion relation the loading force experienced by RNAP due to DNA-surface friction is estimated and discussed. (+info)Nanometer scale organization of mixed surfactin/phosphatidylcholine monolayers. (5/387)
Mixed monolayers of the surface-active lipopeptide surfactin-C(15) and of dipalmitoyl phosphatidylcholine (DPPC) were deposited on mica and their nanometer scale organization was investigated using atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). AFM topographic images revealed phase separation for mixed monolayers prepared at 0.1, 0.25, and 0.5 surfactin molar ratios. This was in agreement with the monolayer properties at the air-water interface indicating a tendency of the two compounds to form bidimensional domains in the mixed systems. The step height measured between the surfactin and the DPPC domains was 1.2 +/- 0.1 nm, pointing to a difference in molecular orientation: while DPPC had a vertical orientation, the large peptide ring of surfactin was lying on the mica surface. The N/C atom concentration ratios obtained by XPS for pure monolayers were compatible with two distinct geometric models: a random layer for surfactin and for DPPC, a layer of vertically-oriented molecules in which the polar headgroups are in contact with mica. XPS data for mixed systems were accounted for by a combination of the two pure monolayers, considering respective surface coverages that were in excellent agreement with those measured by AFM. These results illustrate the complementarity of AFM and XPS to directly probe the molecular organization of multicomponent monolayers. (+info)An ex-vivo investigation into the effect of bracket displacement on the resistance to sliding. (6/387)
This ex-vivo study investigated the effect that repeated bracket displacement has on sliding friction and the magnitude of bracket displacement, and hence tooth movement, required to release bracket/archwire binding. The design consisted of an ex-vivo laboratory study. A jig was designed that allowed repeated displacement of a bracket to occur, while the resistance to sliding (friction) was measured using an Instron universal testing machine. One type of stainless steel bracket was used in conjunction with four archwire types (0.016-inch stainless steel, 0.019 x 0.025-inch stainless steel, 0.021 x 0.025-inch stainless steel, 0.019 x 0.025-inch beta-titanium) and four magnitudes of displacement. Repeated bracket displacement has a significant effect on the sliding resistance at the bracket/archwire interface (P < 0.001). The reduction in sliding resistance noted with displacement depended on the archwire. Over the range of displacements tested, there was an 85 and 80 per cent reduction associated with 0.021 x 0.025-inch and 0.019 x 0.025-inch stainless steel, respectively. For 0.019 x 0.025-inch beta-titanium and 0.016-inch stainless steel, these reductions were 27 and 19 per cent, respectively. The importance of true friction, given the likelihood of bracket and/or archwire displacements in vivo, may be lessened. (+info)Keratocytes pull with similar forces on their dorsal and ventral surfaces. (7/387)
As cells move forward, they pull rearward against extracellular matrices (ECMs), exerting traction forces. However, no rearward forces have been seen in the fish keratocyte. To address this discrepancy, we have measured the propulsive forces generated by the keratocyte lamella on both the ventral and the dorsal surfaces. On the ventral surface, a micromachined device revealed that traction forces were small and rearward directed under the lamella, changed direction in front of the nucleus, and became larger under the cell body. On the dorsal surface of the lamella, an optical gradient trap measured rearward forces generated against fibronectin-coated beads. The retrograde force exerted by the cell on the bead increased in the thickened region of the lamella where myosin condensation has been observed (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G. G. Borisy. 1997. J. Cell Biol. 139:397-415). Similar forces were generated on both the ventral (0.2 nN/microm(2)) and the dorsal (0.4 nN/microm(2)) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts. The correlation between the level of traction force and the density of myosin suggests a model for keratocyte movement in which myosin condensation in the perinuclear region generates rearward forces in the lamella and forward forces in the cell rear. (+info)Reconstitution of Listeria motility: implications for the mechanism of force transduction. (8/387)
Listeria monocytogenes and some other infectious bacteria polymerize their host cell's actin into tails that propel the bacteria through the cytoplasm. Here we show that reconstitution of this behavior in simpler media resolves two aspects of the mechanism of force transduction. First, since dilute reconstitution media have no cytoskeleton, we consider what keeps the tail from being pushed backward rather than the bacterium being propelled forward. The dependence of the partitioning of motion on the friction coefficient of the tail is derived. Consistent with experiments, we find that the resistance of the tail to motion is sensitive to its length. That even small tails are stationary in intact cells is attributed to anchoring to the cytoskeleton. Second, the comparatively low viscosity of some reconstitution media magnifies the effects of diffusion, such that a large gap will develop between the bacterium and its tail if they are unattached. At the viscosities of diluted platelet extracts, steady-state gaps of several bacterium lengths are predicted. Since such gaps are not observed, we conclude that Listeria must be attached to their tails. We consider what purposes such attachments might serve under physiological conditions. The implications for related pathogens and amoeboid locomotion are also discussed. (+info)I'm sorry for any confusion, but "friction" is not a term that has a specific medical definition. Friction is a physical concept that describes the force that resists the sliding of one surface over another. It is commonly described as the "roughness" between two surfaces. While friction can have effects on various biological processes and medical devices, it does not have a unique medical meaning in and of itself.
In medical terms, lubrication refers to the application of a slippery substance or fluid to reduce friction and facilitate smooth movement between two surfaces. This is particularly relevant in the context of human anatomy, where lubrication plays a crucial role in various bodily functions. For instance, the mucous membranes that line body cavities such as the mouth, vagina, and rectum secrete fluids to provide lubrication for easy movement of tissues and foreign substances (like food or during sexual intercourse). Similarly, synovial fluid, a viscous substance found in joints, provides lubrication that enables smooth articulation between bones. Artificial lubricants may also be used in medical procedures to facilitate the insertion and movement of medical devices such as catheters or endoscopes.
Medical definitions of "lubricants" refer to substances that are used to reduce friction between two surfaces in medical procedures or devices. They can be used during various medical examinations, surgeries, or when inserting medical equipment, such as catheters, to make the process smoother and more comfortable for the patient.
Lubricants used in medical settings may include water-based gels, oil-based jellies, or silicone-based lubricants. It's important to choose a lubricant that is safe and suitable for the specific medical procedure or device being used. For example, some lubricants may not be compatible with certain medical materials or may need to be sterile.
It's worth noting that while lubricants are commonly used in medical settings, they should not be used as a substitute for proper medical care or treatment. If you have any concerns about your health or medical condition, it's important to consult with a qualified healthcare professional.
Orthodontic appliance design refers to the creation and development of medical devices used in orthodontics, which is a branch of dentistry focused on the diagnosis, prevention, and correction of dental and facial irregularities. The design process involves creating a customized treatment plan for each patient, based on their specific needs and goals.
Orthodontic appliances can be removable or fixed and are used to move teeth into proper alignment, improve jaw function, and enhance the overall appearance of the smile. Some common types of orthodontic appliances include braces, aligners, palatal expanders, and retainers.
The design of an orthodontic appliance typically involves several factors, including:
1. The specific dental or facial problem being addressed
2. The patient's age, overall health, and oral hygiene habits
3. The patient's lifestyle and personal preferences
4. The estimated treatment time and cost
5. The potential risks and benefits of the appliance
Orthodontic appliance design is a complex process that requires a thorough understanding of dental anatomy, biomechanics, and materials science. It is typically performed by an orthodontist or a dental technician with specialized training in this area. The goal of orthodontic appliance design is to create a device that is both effective and comfortable for the patient, while also ensuring that it is safe and easy to use.
I'm sorry for any confusion, but "Stainless Steel" is not a medical term. It is a type of steel that contains at least 10.5% chromium content by mass, and usually contains nickel as well. The chromium forms a passive film that protects the metal from corrosion and staining. Stainless steel is widely used in various industries including medicine, for example, in medical equipment and surgical instruments due to its resistance to rust and corrosion.
Elastomers are a type of polymeric material that exhibit elastic behavior when subjected to deforming forces. They have the ability to return to their original shape and size after being stretched or compressed, making them ideal for use in applications where flexibility, resilience, and durability are required.
Elastomers are composed of long chains of repeating molecular units called monomers, which are cross-linked together to form a three-dimensional network. This cross-linking gives elastomers their unique properties, such as high elasticity, low compression set, and resistance to heat, chemicals, and weathering.
Some common examples of elastomers include natural rubber, silicone rubber, neoprene, nitrile rubber, and polyurethane. These materials are used in a wide range of applications, from automotive parts and medical devices to footwear and clothing.
Surface properties in the context of medical science refer to the characteristics and features of the outermost layer or surface of a biological material or structure, such as cells, tissues, organs, or medical devices. These properties can include physical attributes like roughness, smoothness, hydrophobicity or hydrophilicity, and electrical conductivity, as well as chemical properties like charge, reactivity, and composition.
In the field of biomaterials science, understanding surface properties is crucial for designing medical implants, devices, and drug delivery systems that can interact safely and effectively with biological tissues and fluids. Surface modifications, such as coatings or chemical treatments, can be used to alter surface properties and enhance biocompatibility, improve lubricity, reduce fouling, or promote specific cellular responses like adhesion, proliferation, or differentiation.
Similarly, in the field of cell biology, understanding surface properties is essential for studying cell-cell interactions, cell signaling, and cell behavior. Cells can sense and respond to changes in their environment, including variations in surface properties, which can influence cell shape, motility, and function. Therefore, characterizing and manipulating surface properties can provide valuable insights into the mechanisms of cellular processes and offer new strategies for developing therapies and treatments for various diseases.
Orthodontic brackets are small square attachments that are bonded to the teeth or bands that are attached to the back molars. They have a slot in which the orthodontic archwire fits and is held in place. The bracket can be made of stainless steel, ceramic, plastic or a combination of these materials. They play an essential role in moving the teeth into the desired position during orthodontic treatment.
Viscosity is a physical property of a fluid that describes its resistance to flow. In medical terms, viscosity is often discussed in relation to bodily fluids such as blood or synovial fluid (found in joints). The unit of measurement for viscosity is the poise, although it is more commonly expressed in millipascals-second (mPa.s) in SI units. Highly viscous fluids flow more slowly than less viscous fluids. Changes in the viscosity of bodily fluids can have significant implications for health and disease; for example, increased blood viscosity has been associated with cardiovascular diseases, while decreased synovial fluid viscosity can contribute to joint pain and inflammation in conditions like osteoarthritis.
I'm sorry for any confusion, but "physical phenomena" is not a term typically used in medical definitions. It is a broader term that refers to observable events or processes in the natural world that can be explained by physical laws and principles. This might include things like gravity, electromagnetism, or motion.
If you're looking for medical definitions related to physical phenomena, you might consider terms like "physical examination," which refers to the process of evaluating a patient's health status using observation, palpation, percussion, and auscultation to assess various body systems. Or, you might consider "physiological response," which refers to the body's natural reaction to a stimulus or change in environment.
If you meant something different by "physical phenomena" in a medical context, could you please provide more context or clarify your question? I'm here to help!
I'm happy to help! However, I must clarify that "materials testing" is not a medical term per se. It is a term used in various fields, including engineering and materials science, to describe the process of subjecting materials to different tests to evaluate their properties and performance under various conditions.
In the context of medical devices or implants, materials testing may refer to the evaluation of the physical and mechanical properties of materials used in their construction. These tests can include assessments of strength, durability, biocompatibility, and other factors that are critical to ensuring the safety and efficacy of medical devices.
Medical device manufacturers must comply with regulatory standards for materials testing to ensure that their products meet specific requirements for performance, safety, and quality. These standards may vary depending on the type of device, its intended use, and the country or region in which it will be marketed and sold.
Biomechanics is the application of mechanical laws to living structures and systems, particularly in the field of medicine and healthcare. A biomechanical phenomenon refers to a observable event or occurrence that involves the interaction of biological tissues or systems with mechanical forces. These phenomena can be studied at various levels, from the molecular and cellular level to the tissue, organ, and whole-body level.
Examples of biomechanical phenomena include:
1. The way that bones and muscles work together to produce movement (known as joint kinematics).
2. The mechanical behavior of biological tissues such as bone, cartilage, tendons, and ligaments under various loads and stresses.
3. The response of cells and tissues to mechanical stimuli, such as the way that bone tissue adapts to changes in loading conditions (known as Wolff's law).
4. The biomechanics of injury and disease processes, such as the mechanisms of joint injury or the development of osteoarthritis.
5. The use of mechanical devices and interventions to treat medical conditions, such as orthopedic implants or assistive devices for mobility impairments.
Understanding biomechanical phenomena is essential for developing effective treatments and prevention strategies for a wide range of medical conditions, from musculoskeletal injuries to neurological disorders.
I'm sorry for any confusion, but "textiles" is not a term that is typically used in a medical context. In general, textiles refer to the broad category of flexible materials made by weaving, knitting, braiding, or felting fibers together. They include things like clothing, upholstery, and other soft goods.
In a medical setting, terms such as "medical textiles" or "healthcare textiles" might be used to refer to textile-based products that are specifically designed for use in medical applications, such as bandages, wound dressings, sutures, and implantable materials. These products must meet strict regulatory requirements to ensure their safety and effectiveness.
However, it's important to note that while some healthcare professionals may be familiar with the term "textiles" in this context, it is not a standard medical term and would not be used in a formal medical definition.
I'm sorry for any confusion, but "physics" is not a term that has a medical definition. Physics is a branch of science that deals with the study of matter, energy, and their interactions. It may be studied in the context of medical physics, which involves the application of physical principles to medicine, such as in the use of radiation therapy for cancer treatment or imaging techniques like MRI and CT scans. However, "physics" itself is not a medical term with a specific definition within the field of medicine.
Dental alloys are materials made by combining two or more metals to be used in dental restorations, such as crowns, bridges, fillings, and orthodontic appliances. These alloys can be classified into three main categories based on their composition:
1. Precious Alloys: Predominantly composed of precious metals like gold, platinum, palladium, and silver. They are highly corrosion-resistant, biocompatible, and durable, making them suitable for long-term use in dental restorations. Common examples include high noble (gold) alloys and noble alloys.
2. Base Metal Alloys: Contain primarily non-precious metals like nickel, chromium, cobalt, and beryllium. They are more affordable than precious alloys but may cause allergic reactions or sensitivities in some patients. Common examples include nickel-chromium alloys and cobalt-chromium alloys.
3. Castable Glass Ionomer Alloys: A combination of glass ionomer cement (GIC) powder and metal liquid, which can be cast into various dental restorations. They have the advantage of being both strong and adhesive to tooth structure but may not be as durable as other alloy types.
Each type of dental alloy has its unique properties and applications, depending on the specific clinical situation and patient needs. Dental professionals consider factors like cost, biocompatibility, mechanical properties, and esthetics when selecting an appropriate alloy for a dental restoration.
Mechanical stress, in the context of physiology and medicine, refers to any type of force that is applied to body tissues or organs, which can cause deformation or displacement of those structures. Mechanical stress can be either external, such as forces exerted on the body during physical activity or trauma, or internal, such as the pressure changes that occur within blood vessels or other hollow organs.
Mechanical stress can have a variety of effects on the body, depending on the type, duration, and magnitude of the force applied. For example, prolonged exposure to mechanical stress can lead to tissue damage, inflammation, and chronic pain. Additionally, abnormal or excessive mechanical stress can contribute to the development of various musculoskeletal disorders, such as tendinitis, osteoarthritis, and herniated discs.
In order to mitigate the negative effects of mechanical stress, the body has a number of adaptive responses that help to distribute forces more evenly across tissues and maintain structural integrity. These responses include changes in muscle tone, joint positioning, and connective tissue stiffness, as well as the remodeling of bone and other tissues over time. However, when these adaptive mechanisms are overwhelmed or impaired, mechanical stress can become a significant factor in the development of various pathological conditions.
Artificial saliva is a synthetic solution that mimics the chemical composition and properties of natural saliva. It is often used for patients with dry mouth (xerostomia) caused by conditions such as Sjögren's syndrome, radiation therapy, or certain medications that reduce saliva production. Artificial saliva may contain ingredients like carboxymethylcellulose, mucin, and electrolytes to provide lubrication, moisture, and pH buffering capacity similar to natural saliva. It can help alleviate symptoms associated with dry mouth, such as difficulty speaking, swallowing, and chewing, as well as protect oral tissues from irritation and infection.
'Adhesiveness' is a term used in medicine and biology to describe the ability of two surfaces to stick or adhere to each other. In medical terms, it often refers to the property of tissues or cells to adhere to one another, as in the case of scar tissue formation where healing tissue adheres to adjacent structures.
In the context of microbiology, adhesiveness can refer to the ability of bacteria or other microorganisms to attach themselves to surfaces, such as medical devices or human tissues, which can lead to infection and other health problems. Adhesives used in medical devices, such as bandages or wound dressings, also have adhesiveness properties that allow them to stick to the skin or other surfaces.
Overall, adhesiveness is an important property in many areas of medicine and biology, with implications for wound healing, infection control, and the design and function of medical devices.
"Weight-bearing" is a term used in the medical field to describe the ability of a body part or limb to support the weight or pressure exerted upon it, typically while standing, walking, or performing other physical activities. In a clinical setting, healthcare professionals often use the term "weight-bearing exercise" to refer to physical activities that involve supporting one's own body weight, such as walking, jogging, or climbing stairs. These exercises can help improve bone density, muscle strength, and overall physical function, particularly in individuals with conditions affecting the bones, joints, or muscles.
In addition, "weight-bearing" is also used to describe the positioning of a body part during medical imaging studies, such as X-rays or MRIs. For example, a weight-bearing X-ray of the foot or ankle involves taking an image while the patient stands on the affected limb, allowing healthcare providers to assess any alignment or stability issues that may not be apparent in a non-weight-bearing position.
I'm sorry for any confusion, but "hydrodynamics" is not a term typically used in medical definitions. Hydrodynamics is a branch of physics that deals with the motion of fluids and the forces acting on them. It is commonly used in fields such as engineering, particularly in the design of fluid-handling systems, and in the study of phenomena like water waves and blood flow in certain scientific contexts.
If you have any questions related to medicine or health, I would be happy to try to help answer those for you!
Friction
Belt friction
Friction drilling
Friction torque
Friction (disambiguation)
Friction surfacing
Pulpit Friction
Bobby Friction
Friction drive
Dynamical friction
Pump Friction
Fault friction
Friction Groove
Friction drum
Friction extrusion
Boundary friction
Friction primer
Friction modifier
ABS Friction
Friction burn
Science Friction
Friction blister
Operation Friction
Friction idiophone
Friction tape
Friction welding
Friction, Baby
Friction Acoustics
Friction sensitivity
Les Friction
Friction - Wikipedia
Friction
Belt friction - Wikipedia
friction
Tire/Ice Friction Values
Multimedia Gallery - Friction & Heat | NSF - National Science Foundation
Friction Costs - The Escapist
PhET-søk: friction
What is an example of reducing friction? - Answers
Friction Experiment - PhET-bidrag
Easy Acceleration / Friction question
Fighting-Friction
Friction - National Council of Teachers of English
Advances in Wet Friction Materials 75 Years of Progress
Friction based material sorter (Patent) | DOE Patents
Friction! - Always - Free Music Archive
Friction Blisters: Practice Essentials, Pathophysiology, Etiology
FRICTION Synonyms: 72 Similar and Opposite Words | Merriam-Webster Thesaurus
7 Ways to Reduce Friction Between Remote and Onsite Employees
How friction leads to static electricity - ScienceBlog.com
Optimal Corporate Taxation Under Financial Frictions | NBER
Friction Slab : Photos, Diagrams & Topos : SummitPost
Friction Free: Streamlining the Customer Journey
Friction Pens Archives - Steve Spangler Science
friction-stir welding | ASSEMBLY
Salesforce: Retail Techniques to Reduce Friction and Boost Revenue - Salesforce Blog
Causation vs. constitution: loosening the friction | Coincidence Analysis | UiB
Uniaxial orientation of P3HT film prepared by soft friction transfer method | Scientific Reports
Designing Friction For A Better User Experience - Smashing Magazine
Friction Stir Welding of Aluminum... preview & related info | Mendeley
Coefficient6
- 2. Dragging coefficient of friction μ g {\displaystyle \mu _{g}} and angle α {\displaystyle \alpha } are satisfying the following criteria for all points of the curve − μ g (wikipedia.org)
- This generalization has been obtained by Konyukhov A., There are certain factors that help determine the value of the friction coefficient. (wikipedia.org)
- Braking deceleration values in units of gravity on ice surfaces have typically applied to the locked and sliding wheel with a representative friction coefficient of 0.10 ascribed. (sae.org)
- 7 ] proposed a damage model of bearings based on the change of the friction coefficient and discussed the failure state of movable bearings in earthquakes. (hindawi.com)
- Preload, Coefficient of Friction, and Thread Friction in an Implant-Abutment-Screw Complex. (bvsalud.org)
- To examine the screw preload, coefficient of friction (COF), and tightening torque needed to overcome the thread friction of an implant-abutment-screw complex. (bvsalud.org)
20231
- Dec. 1, 2023 Friction is hard to predict and control, especially since surfaces that come in contact are rarely perfectly flat. (sciencedaily.com)
Reducing Friction3
- What is an example of reducing friction? (answers.com)
- What is an example of reducing friction in the moving parts of machinery? (answers.com)
- An equality of benefits and scheduling is key to reducing friction, agreed Ellen Ernst Kossek, a management professor at Purdue University and co-author of CEO of Me: Creating a Life That Works in the Flexible Job Age (FT Press, 2007). (shrm.org)
Energy dissipation3
- The energy dissipation characteristics of the laminated rubber bearings with two end plates, rubber bearings with unilateral friction sliding, and lead rubber bearing (LRB) under low-frequency cyclic loads were compared and analyzed. (hindawi.com)
- The rubber bearings with unilateral friction sliding had similar energy dissipation capacities compared to the LRB. (hindawi.com)
- However, the research on the ultimate failure state and the energy dissipation due to the friction sliding of the bearings is insufficient. (hindawi.com)
Types of friction3
- There are several types of friction: Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact. (wikipedia.org)
- Another important consequence of many types of friction can be wear, which may lead to performance degradation or damage to components. (wikipedia.org)
- The Boston Consulting Group's e-Friction Index ranks economies according to four types of friction: infrastructure, industry, individual, and information. (bcg.com)
Increase the friction1
- Moisture on the skin surface may either increase the friction force or, in the case of very moist skin, decrease it temporarily by providing lubrication. (medscape.com)
Kinetic energy5
- Kinetic energy is converted to thermal energy whenever motion with friction occurs, for example when a viscous fluid is stirred. (wikipedia.org)
- In the presence of friction, some kinetic energy is always transformed to thermal energy, so mechanical energy is not conserved. (wikipedia.org)
- In machines, friction quietly steals power by wasting kinetic energy in the form of heat. (acs.org)
- So I am wondering, since 1/2mv^2 is for kinetic energy, and the velocity here is 1/8th, does it mean the friction is 1/8th or 1/64th? (physicsforums.com)
- Like if a friction surface is moved twice as fast does the kinetic energy, being 4 times higher produce 4 times as much heat or twice as much heat? (physicsforums.com)
Lubricant3
- Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces. (wikipedia.org)
- Conditions under which the belt and pulleys are operating - The friction between the belt and pulley may decrease substantially if the belt happens to be muddy or wet, as it may act as a lubricant between the surfaces. (wikipedia.org)
- One way to reduce friction is to use a lubricant. (answers.com)
Lubrication1
- The study of tribology deals with friction, wear, and lubrication. (anton-paar.com)
Surfaces9
- Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. (wikipedia.org)
- Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces. (wikipedia.org)
- Amontons presented the nature of friction in terms of surface irregularities and the force required to raise the weight pressing the surfaces together. (wikipedia.org)
- he proposed that friction was the force necessary to tear the adhering surfaces apart. (wikipedia.org)
- The effect of the time of repose was explained by Pieter van Musschenbroek (1762) by considering the surfaces of fibrous materials, with fibers meshing together, which takes a finite time in which the friction increases. (wikipedia.org)
- Friction is the force that opposes the relative motion or tendency of such motion of two surfaces in contact. (sciencedaily.com)
- What's worse, whenever surfaces rub, friction eventually causes the materials to wear down, ending an object's useful life. (acs.org)
- As the axle grinds against the surface of the wheel, it has friction, and as the wheel is forcibly rotated (such as by a team of 12 oxen pulling with great force) the friction of the two surfaces causes temperatures at their contact points to increase. (physicsforums.com)
- Friction (the constant rubbing of 2 surfaces against one another) in the oral cavity may result in the development of clinically observable white patches. (medscape.com)
Mechanical8
- In the long course of the development of the law of conservation of energy and of the first law of thermodynamics, friction was recognised as a mode of conversion of mechanical work into heat. (wikipedia.org)
- July 25, 2022 For machines with mechanical elements, friction is an unavoidable enemy. (sciencedaily.com)
- Researchers who study friction, part of a field of mechanical engineering called tribology, say that new performance materials hold the promise of vastly reducing the effect of friction on mechanical parts, including car engines and wind turbine gears. (acs.org)
- This paper focused on the Mechanical and Microstructural changes of aluminum alloy 6082-T6 welded joints formed by Friction Stir Welding Technique by varying process. (mendeley.com)
- In summary, the conversation discussed the mechanical advantages of a wheel, specifically in relation to its friction and heat generation. (physicsforums.com)
- If you don't appreciate the mechanical poetry that is pushing a derailleur through gears entirely on muscle memory and feel, LinkGlide is not going to make you covet a friction setup. (nsmb.com)
- 12 , 13 ] proposed the sliding friction mechanical model of rubber bearings during an earthquake and analyzed the effect of the bearing sliding on the seismic performance of bridges. (hindawi.com)
- [ 4 ] Increasing skin hydration caused sex-specific changes in the mechanical properties and/or surface topography, as the friction of female skin demonstrated significantly higher moisture sensitivity. (medscape.com)
20221
- 22, 2022 Chemists and physicists shed light on a crucial aspect of friction: how things begin to slide. (sciencedaily.com)
Tribology1
- The classic laws of sliding friction were discovered by Leonardo da Vinci in 1493, a pioneer in tribology, but the laws documented in his notebooks were not published and remained unknown. (wikipedia.org)
Fundamental2
- Friction is not itself a fundamental force. (wikipedia.org)
- This is a great example of how fundamental research can explain everyday phenomena which hadn't been understood previously, and of how research in one area - in this case friction and wear - can lead to unexpected advances in another area," said Andrew Wells, a program director at the National Science Foundation (NSF), which funded the research. (scienceblog.com)
Pulley1
- Pulley with friction, how to get the friction in the pulley? (physicsforums.com)
Surface12
- With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities (see Figure 1). (wikipedia.org)
- Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. (wikipedia.org)
- Dry friction arises from a combination of inter-surface adhesion, surface roughness, surface deformation, and surface contamination. (wikipedia.org)
- Belt friction is a term describing the friction forces between a belt and a surface, such as a belt wrapped around a bollard. (wikipedia.org)
- Erythema and superficial blisters, a friction-induced injury referred to as pool toes, may be evident on the plantar surface of the toes or on the heels in contact with a rough pool surface. (medscape.com)
- 0.916 inches of surface friction travel per inch of road travel, vs. 0.0833 inches of surface friction per inch of road travel. (physicsforums.com)
- Obviously the static friction for the rotating wheel with the larger axle is higher, because of the larger surface, but what about the kinetic friction? (physicsforums.com)
- This global friction surface enumerates land-based travel speed for all land pixels between 85 degrees north and 60 degrees south for a nominal year 2019. (google.com)
- In cases of large earthquakes, the relative friction sliding between the bearing and the contact surface of the pier reduces the horizontal seismic load transmitted to the substructure, which plays a role in seismic isolation [ 1 ]. (hindawi.com)
- Friction is the force that act oppose relative motion of two surface. (powtoon.com)
- It depends on toughness of the surface and force push the surface together As i know, there are 4 type of friction which is static, rolling, sliding and fluid. (powtoon.com)
- The present paper compares the friction surface of self-ligated brackets and conventional brackets, their advantages and disadvantages, based in studies wich evaluates such factors as the materials of wires and brackets, the surface condition of the wires and the brackets fit, the cable section, the torque on the bracket-wire interface, the angle of the brackets and strength of their ligations, the saline and oral functions. (bvsalud.org)
Bearings2
- It was noted that smaller diameter plain bearings move the friction nearer to the axis of rotation, resulting in a reduction in torque and power. (physicsforums.com)
- To fully ascertain the ultimate shear failure state and the friction sliding performance of laminated rubber bearings in bridges, a series of cyclic loading tests were conducted. (hindawi.com)
Static7
- This view was further elaborated by Bernard Forest de Bélidor and Leonhard Euler (1750), who derived the angle of repose of a weight on an inclined plane and first distinguished between static and kinetic friction.John Theophilus Desaguliers (1734) first recognized the role of adhesion in friction. (wikipedia.org)
- The distinction between static and dynamic friction is made in Coulomb's friction law (see below), although this distinction was already drawn by Johann Andreas von Segner in 1758. (wikipedia.org)
- Shouldn't this be kinetic friction instead of static friction! (physicsforums.com)
- Greek philosopher Thales of Miletus first reported friction-induced static electricity in 600 B.C. After rubbing amber with fur, he noticed the fur attracted dust. (scienceblog.com)
- The conversation also touched on the difference between static and kinetic friction and how they are affected by velocity. (physicsforums.com)
- Friction comes in static friction, and kinetic friction. (physicsforums.com)
- These factors influence the friction of both self-ligated brackets and conventional brackets, but all self-bonded brackets showed lower friction values compared to those of conventional brackets in both (static and kinetic) frictions. (bvsalud.org)
Search4
- I do so by assuming search frictions in the labor market. (repec.org)
- Search Frictions, Real Rigidities and Inflation Dynamics ," CEP Discussion Papers dp0822, Centre for Economic Performance, LSE. (repec.org)
- Search frictions, real rigidities and inflation dynamics ," LSE Research Online Documents on Economics 19692, London School of Economics and Political Science, LSE Library. (repec.org)
- Search frictions, real rigidities and inflation dynamics ," Working Papers 0806, Banco de España. (repec.org)
Force9
- Internal friction is the force resisting motion between the elements making up a solid material while it undergoes deformation. (wikipedia.org)
- Friction is a non-conservative force - work done against friction is path dependent. (wikipedia.org)
- This experiment will help you understand how friction force cause a material to heat up. (colorado.edu)
- You multiply it by the normal force to get the (magnitude of the) friction force: F friction = µN. (physicsforums.com)
- On Earth, friction is a physical force, like gravity, that people take for granted. (acs.org)
- In regions of the body where the stratum corneum is thinner, a repeated friction force causes the stratum corneum to erode, and instead of a blister, an erosion or abrasion occurs. (medscape.com)
- The likelihood of forming a friction blister at susceptible sites is based on the magnitude of the frictional force and the number of times an object moves across the skin (ie, shear cycles). (medscape.com)
- however, friction tends to increase with prolonged application of the external force. (medscape.com)
- [ 3 ] Wearing socks with low friction against the foot skin reduced the plantar shear force on the skin more than a sock with low friction against the insole. (medscape.com)
Grip1
- Modern, derailleur-based indexed shifting is much newer, as you note, and has become pretty reliable, albeit more complex, and potentially more expensive and difficult to service than friction shifting (getting a frayed cable out of an STI lever can be a challenge, and replacing a worn unit is often more cost effective than rebuilding it, and some grip-shift units are not worth bothering trying to service). (bikeforums.net)
Belt6
- Belt friction can be modeled by the Belt friction equation. (wikipedia.org)
- In practice, the theoretical tension acting on the belt or rope calculated by the belt friction equation can be compared to the maximum tension the belt can support. (wikipedia.org)
- Mountain climbers and sailing crews demonstrate a working knowledge of belt friction when accomplishing tasks with ropes, pulleys, bollards and capstans. (wikipedia.org)
- This also applies to extremely dry or warm conditions which will evaporate any water naturally found in the belt, nominally making friction greater. (wikipedia.org)
- An understanding of belt friction is essential for sailing crews and mountain climbers. (wikipedia.org)
- Here, we investigate whether a planet scattered away from the giant-planet region could be lifted to an orbit similar to the one suggested for Planet Nine through dynamical friction with a cold, distant planetesimal belt. (lu.se)
Mechanics2
- The Mechanics of Friction in Rope Rescue (PDF). (wikipedia.org)
- Overall, the discussion aimed to understand the various factors involved in wheel mechanics and their impact on friction and heat generation. (physicsforums.com)
Content1
- Information-related friction includes the volume of content available in a local language, a country's commitment to Internet openness, and the obstacles to accessing certain types of content. (bcg.com)
Torque3
- The conversation also explored the concept of work and how it relates to friction, torque, and power. (physicsforums.com)
- The _torque_ caused by friction between wheel and ground is usually the same or similar to the torque at the axle. (physicsforums.com)
- Friction would be related to torque which in turn would be related to acceleration and inertia of the non-driven wheel. (physicsforums.com)
Describes2
- Fluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. (wikipedia.org)
- The study from Facebook, KPMG and Nielsen - Eliminating friction in automobile path to purchase - describes friction as consumer dropout during the path to purchase because of incremental steps or non-essential inconveniences. (warc.com)
Calculation1
- The complexity of these interactions makes the calculation of friction from first principles difficult and it is often easier to use empirical methods for analysis and the development of theory. (wikipedia.org)
Increases1
- Giving your visitors multiple options to choose from might seem polite, however, more often than not, our tests show that this only increases the Friction a visitor experiences in a conversion process. (marketingexperiments.com)
Conventional2
- The orientation factor was 17 times higher than that of a film prepared using a conventional friction transfer technique at a high temperature of 120 °C. In addition, an oriented film with a thickness of 40 nm was easily picked up and transferred to another substrate. (nature.com)
- The resultant orientation factor was greater than that for a film prepared by conventional friction transfer on a Teflon plate heated at 120 °C. The soft friction transfer method presented here does not require high temperature, a glove box, or vacuum equipment, but provides uniaxial oriented films by a facile process that involves brushing a soft fabric on the substrate at room temperature. (nature.com)
Ladder1
- This report updates the index and expands on that analysis, showing economies how they can move up the e-friction ladder. (bcg.com)
Https2
- Tire/Ice Friction Values," SAE Technical Paper 960959, 1996, https://doi.org/10.4271/960959 . (sae.org)
- Merriam-Webster.com Thesaurus , Merriam-Webster, https://www.merriam-webster.com/thesaurus/friction. (merriam-webster.com)
Joints1
- Wear and damage because of friction had rendered the joints inoperable. (acs.org)
Creates3
- In Leslie's view, friction should be seen as a time-dependent process of flattening, pressing down asperities, which creates new obstacles in what were cavities before. (wikipedia.org)
- Friction always creates heat. (nsf.gov)
- She is an avid runner, which creates a lot of friction on her skin. (medscape.com)
Overcome1
- Here, the scalable bottom-up fabrication of wafer-scale carbon nanotube (CNT) membranes with highly aligned, low-friction, straight-channels/capillaries and narrow pore-diameter distributions (≈0.5-4.5 nm) is demonstrated, to overcome persistent challenges in hemofiltration/hemodialysis. (lu.se)
Materials6
- This paper traces the advancements made in wet friction materials. (sae.org)
- The paper concludes by describing the performance characteristics of wet friction materials currently available. (sae.org)
- Originally developed for joining aluminum, friction stir welding is now being applied to other materials, including steel, copper, titanium and even nylon. (assemblymag.com)
- The Paper Friction Materials market research report is proficient and top to bottom research by specialists on the current state of the industry. (openpr.com)
- The Paper Friction Materials research report offers significant bits of information into the business focus from the early stage including some steady techniques chalked out by perceptible market pioneers to develop a strong foothold and development in the business. (openpr.com)
- Moreover, the important areas of the Paper Friction Materials market are also assessed on the basis of their performance. (openpr.com)
Aluminum1
- Friction Stir Welding of Aluminum. (mendeley.com)
Resistance2
- Friction stir spot welding has many advantages compared with riveting or resistance spot welding. (assemblymag.com)
- The friction transfer method is conducted by sliding a solid polymer material on a substrate heated at temperatures in the range of 140-180 °C. However, for flexible electronic devices to be integrated on a polymer substrate, such temperatures may be too high because the material typically has low heat resistance. (nature.com)
Reduce4
- That means retailers must reduce friction and create seamless experiences if they want to grow revenue. (salesforce.com)
- But by using mobile more effectively in the media mix, it is possible to reduce media friction and increase sales opportunity, the report said. (warc.com)
- Already, around seven in ten car purchases in India are influenced by smartphone, a figure that will increase to eight in ten during the next five years, so optimising mobile spending could reduce media friction to 7.8% and unlock one million units of sales opportunity. (warc.com)
- Do pencil reduce the friction between box and table? (powtoon.com)
Curve1
- There is a learning curve in achieving quick, reliable friction shifting, but as my music teacher daughter put it, it's like learning to play the trombone: practice enough and your hand eventually learns where it has to stop. (bikeforums.net)
Thick2
- Friction blisters tend to occur in areas of thick adherent stratum corneum (eg, palms, soles, heels, dorsa of fingers). (medscape.com)
- Friction hinge for non-grooved 3/16 or ¼-inch thick panels. (clearsonic.com)
Cellulitis2
- Prompt attention to friction blisters is important to prevent the development of secondary impetigo with possible cellulitis and sepsis. (medscape.com)
- Friction blisters and cellulitis in a navy recruit population. (medscape.com)
Material1
- These determining factors are: Belting material used - The age of the material also plays a part, where worn out and older material may become more rough or smoother, changing the sliding friction. (wikipedia.org)
Process5
- On the other hand, they also point out that solving the friction problem is an unending process. (acs.org)
- From the user's perspective, such confirmation is an extra step in the process (a friction, actually) but at the same time, they are assured that they will not accidentally perform an action that is hard to undo. (smashingmagazine.com)
- Friction is one of the greatest obstacles to your conversion process, and though most marketers currently have some idea of what Friction is, many are only seeing half the picture. (marketingexperiments.com)
- When asking marketers to identify the Friction associated with a conversion process, the response is often very confident. (marketingexperiments.com)
- However, our research suggests that most of the Friction in a conversion process goes undetected. (marketingexperiments.com)
Plate1
- Shimano's DuraAce rear barcon shifter, seen here on a Paul Components Thumbie plate, can be run in an indexed mode (with clicks for each gear) or a friction mode (without). (nsmb.com)
Design5
- In experience design, friction is usually the opposite of being intuitive or effortless. (smashingmagazine.com)
- In this article, you'll learn when and how friction can be an efficient tool to actually design better experiences. (smashingmagazine.com)
- In experience design, friction is anything that prevents users from accomplishing their goals or getting things done. (smashingmagazine.com)
- In game design, for example, friction is actually required. (smashingmagazine.com)
- But it's not just game design where friction can come in handy. (smashingmagazine.com)
Factors1
- Brennan FH Jr, Jackson CR, Olsen C, Wilson C. Blisters on the battlefield: the prevalence of and factors associated with foot friction blisters during Operation Iraqi Freedom I. Mil Med . (medscape.com)
Rear1
- There's often some confusion as many rear thumb-shifters of yore can be run in both indexed and friction modes. (nsmb.com)
Suggests2
- Our finding suggests that triboelectricity, flexoelectricity and friction are inextricably linked," Marks said. (scienceblog.com)
- However, our research suggests there is a lot of Friction that goes under the radar when it comes to multimedia. (marketingexperiments.com)
Study1
- In a study of 11 men and 11 women, the friction between the inner forearm and a hospital fabric was measured in different hydration states. (medscape.com)
Amount1
- The right amount of friction at the right time is what makes a game challenging enough. (smashingmagazine.com)
Paper1
- Labour Market Frictions, Monetary Policy and Durable Goods ," Working Paper Series of the Department of Economics, University of Konstanz 2012-09, Department of Economics, University of Konstanz. (repec.org)
Skin3
- Friction blisters of the skin commonly occur in active populations. (medscape.com)
- The influence of epidermal hydration on the friction of human skin against textiles was studied. (medscape.com)
- Gerhardt LC, Strässle V, Lenz A, Spencer ND, Derler S. Influence of epidermal hydration on the friction of human skin against textiles. (medscape.com)
Performance2
- 11 ] discussed the effect of the sliding friction of the bearing on the seismic performance of bridges. (hindawi.com)
- The Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) and Thiessen Team USA, Spokane, WA, have developed a pull claw that can be attached to any accessible friction bolt ring to test bolt performance. (cdc.gov)
Opposite1
- John Leslie (1766-1832) noted a weakness in the views of Amontons and Coulomb: If friction arises from a weight being drawn up the inclined plane of successive asperities, why then isn't it balanced through descending the opposite slope? (wikipedia.org)
Create2
Work1
- As a result, friction is rising at some companies between remote employees and those required to work onsite who are jealous of their colleagues' flexibility. (shrm.org)
Report2
- To make it easier for those with an interest in the health and growth of their online economies to "grease the wheels" by reducing the friction that holds back the development of the Internet economy, this report looks at the major causes of e-friction and at how countries can learn from those that faced similar challenges but have managed to address the most significant impediments. (bcg.com)
- In our January 2014 report, The Connected World: Greasing the Wheels of the Internet Economy , which was commissioned by the Internet Corporation for Assigned Names and Numbers (ICANN) as was this update, we identified 55 indicators of "e-friction" that inhibit online activity by consumers, businesses, and governments. (bcg.com)
