resistivity

(noun)

In general, the resistance to electric current of a material; in particular, the degree to which a material resists the flow of electricity.

Related Terms

Examples of resistivity in the following topics:

  • Resistance and Resistivity

    • Resistance and resistivity describe the extent to which an object or material impedes the flow of electric current.
    • Conductance and resistance are reciprocals .
    • What determines resistivity?
    • Its resistance to the flow of current is similar to the resistance posed by a pipe to fluid flow.
    • Identify properties of the material that are described by the resistance and resistivity

  • Resistance to French Rule

  • Dependence of Resistance on Temperature

    • Resistivity and resistance depend on temperature with the dependence being linear for small temperature changes and nonlinear for large.
    • The resistivity of all materials depends on temperature.
    • where ρ0 is the original resistivity and α is the temperature coefficient of resistivity.
    • is the temperature dependence of the resistance of an object, where R0 is the original resistance and R is the resistance after a temperature change T.
    • Compare temperature dependence of resistivity and resistance for large and small temperature changes

  • Mechanisms of Resistance

    • Resistance can be mediated by the environment or the microorganism itself .
    • Intrinsic resistance is considered to be a natural and inherited property with high predictability.
    • Once the identity of the organism is known, the aspects of its anti-microbial resistance are also recognized.
    • On the other hand, acquired resistance results from a change in the organism's genetic makeup.
    • Describe the mechanisms bacteria use to develop antimicrobial resistance and the factors that can lead to it

  • Factors Affecting Pulmonary Ventilation: Airway Resistance

    • Airway resistance refers to resistance in the respiratory tract to airflow.
    • Airway resistance can change over time, especially during an asthma attack when the airways constricts causing an increase in airway resistance.
    • Below is the equation for calculating airway resistance (R).
    • Therefore the resistance to air in the bronchi is greater than the resistance to air in the trachea.
    • Laminar flow (a) has orderly layers and low resistance.

  • Cost and Prevention of Resistance

    • Antimicrobial resistance is a major public health and economic burden on patients, affected communities, and healthcare providers.
    • Patients who are infected with bacterial strains resistant to more than one type or class of drugs (multidrug-resistant organisms, MDRO) often have an increased risk of prolonged illness, extended hospital stay, and mortality.
    • Multidrug resistance forces healthcare providers to use antibiotics that are more expensive or more toxic to the patient.
    • Research and development of new drugs effective against resistant bacterial strains also comes at a cost.
    • Antibiotic misuse is a major cause of the staggering healthcare costs for the treatment of resistant bacterial strains.

  • Relative Resistance of Microbes

    • Endospores are considered the most resistant structure of microbes .
    • They are resistant to most agents that would normally kill the vegetative cells from which they formed.
    • Certain bacterial species are more resistant to treatment than others.
    • Gram-negative bacteria have high natural resistance to some antibiotics.
    • Staphylococcus aureus is one of the major resistant pathogens.

  • Resisitors in Series

    • The total resistance in the circuit with resistors connected in series is equal to the sum of the individual resistances.
    • A measure of this limit on charge flow is called resistance.
    • The total resistance in the circuit is equal to the sum of the individual resistances, since the current has to pass through each resistor in sequence through the circuit.
    • This implies that the total resistance in a series is equal to the sum of the individual resistances.
    • Since all of the current must pass through each resistor, it experiences the resistance of each, and resistances in series simply add up.

  • Introduction to Blood Flow, Pressure, and Resistance

    • Resistance is a term used to define the resistance to flow which must be overcome to push blood through the circulatory system.
    • If resistance increases either pressure must increase to maintain flow, or flow rate must reduce to maintain pressure.
    • With increasing length, increasing viscosity and decreasing radius resistance is increased.
    • The resistance offered by the peripheral circulation is known as the systemic vascular resistance (SVR), while the resistance offered by the vasculature of the lungs is known as the pulmonary vascular resistance (PVR).
    • A relatively constant flow is required by the tissues of the body and so pressure and resistance are altered to maintain this.

  • Combination Circuits

    • This is commonly encountered, especially when wire resistances is considered.
    • In that case, wire resistance is in series with other resistances that are in parallel.
    • Essentially, wire resistance is a series with the resistor.
    • It thus increases the total resistance and decreases the current.
    • Each is identified and reduced to an equivalent resistance, and these are further reduced until a single equivalent resistance is reached.