|
Operating Temperature
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the maximum operating temperature (or peak operating temperature). Outside this range of safe operating temperatures the device may fail. It is one component of reliability engineering. Similarly, biological systems have a viable temperature range, which might be referred to as an "operating temperature". Ranges Most devices are manufactured in several temperature grades. Broadly accepted grades are: *Commercial: 0 ° to 70 °C *Industrial: −40 ° to 85 °C *Military: −55 ° to 125 °C Nevertheless, each manufacturer defines its own temperature grades so designers must pay close attention to actual datasheet spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible to extract energy as heat from a body at that temperature. Temperature is important in all fields of natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit. The integrated circuit is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results (also in binary form) as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system. The integration of a whole CPU onto a single or a few integrated circuits using Very-Large-Scale Integration (VLSI) greatly reduced the cost of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as ''catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruvate by ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypothalamus
The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. In the terminology of neuroanatomy, it forms the ventral part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is the size of an almond. The hypothalamus is responsible for regulating certain metabolic processes and other activities of the autonomic nervous system. It synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls body temperature, hunger, important aspects of parenting and maternal attachment behaviours, thirst, fatigue, sleep, and circadian rhythms. Structure T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertility Awareness
Fertility awareness (FA) refers to a set of practices used to determine the fertile and infertile phases of a woman's menstrual cycle. Fertility awareness methods may be used to avoid pregnancy, to achieve pregnancy, or as a way to monitor gynecological health. Methods of identifying infertile days have been known since antiquity, but scientific knowledge gained during the past century has increased the number, variety, and especially accuracy of methods. Systems of fertility awareness rely on observation of changes in one or more of the primary fertility signs ( basal body temperature, cervical mucus, and cervical position), tracking menstrual cycle length and identifying the fertile window based on this information, or both. Other signs may also be observed: these include breast tenderness and mittelschmerz (ovulation pains), urine analysis strips known as ovulation predictor kits (OPKs), and microscopic examination of saliva or cervical fluid. Also available are computerized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basal Body Temperature
Basal body temperature (BBT or BTP) is the lowest body temperature attained during rest (usually during sleep). It is usually estimated by a temperature measurement immediately after awakening and before any physical activity has been undertaken. This will lead to a somewhat higher value than the true BBT. In women, ovulation causes a sustained increase of at least in BBT. Monitoring BBTs is one way of estimating the day of ovulation. The tendency of a woman to have lower temperatures before ovulation, and higher temperatures afterwards, is known as a biphasic temperature pattern. Charting this pattern may be used as a component of fertility awareness. The BBT of men is comparable to the BBT of women in their follicular phase. Hormonal causes of biphasic patterns The higher levels of estrogen present during the pre-ovulatory (follicular) phase of the menstrual cycle lower BBTs. The higher levels of progesterone released by the corpus luteum after ovulation raise BBTs. Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeostasis
In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium and calcium ions, as well as that of the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in the optimal conditions, and equilibrium is maintained by many regulatory mechanisms: it is thought to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment (the study of such processes in zoology has been called physiological ecology). If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above for six hours. The opposite condition, when body temperature decreases below normal levels, is known as hypothermia. It results when the homeostatic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Battery
Lithium battery may refer to: * Lithium metal battery, a non-rechargeable battery with lithium as an anode ** Rechargeable lithium metal battery, a rechargeable counterpart to the lithium metal battery * Lithium-ion battery, a rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging ** Thin-film lithium-ion battery, a solid-state lithium-ion battery constructed as a thin-film ** Aqueous lithium-ion battery ** Lithium-ion flow battery ** Lithium ion manganese oxide battery * Lithium polymer battery * Lithium–sulfur battery * Lithium-titanate battery * Lithium–air battery * Lithium iron phosphate battery * Nickel–lithium battery * Lithium–silicon battery * Lithium vanadium phosphate battery * Lithium hybrid organic battery See also *List of battery types *Lithium batteries in China *High capacity oceanographic lithium battery pack *Glass battery, which may use a lithium metal electrode *Sub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Cell
A primary battery or primary cell is a battery (a galvanic cell) that is designed to be used once and discarded, and not recharged with electricity and reused like a secondary cell (rechargeable battery). In general, the electrochemical reaction occurring in the cell is not reversible, rendering the cell unrechargeable. As a primary cell is used, chemical reactions in the battery use up the chemicals that generate the power; when they are gone, the battery stops producing electricity. In contrast, in a secondary cell, the reaction can be reversed by running a current into the cell with a battery charger to recharge it, regenerating the chemical reactants. Primary cells are made in a range of standard sizes to power small household appliances such as flashlights and portable radios. Primary batteries make up about 90% of the $50 billion battery market, but secondary batteries have been gaining market share. About 15 billion primary batteries are thrown away worldwide every year, vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistance
The electrical resistance of an object is a measure of its opposition to the flow of electric current. Its reciprocal quantity is , measuring the ease with which an electric current passes. Electrical resistance shares some conceptual parallels with mechanical friction. The SI unit of electrical resistance is the ohm (), while electrical conductance is measured in siemens (S) (formerly called the 'mho' and then represented by ). The resistance of an object depends in large part on the material it is made of. Objects made of electrical insulators like rubber tend to have very high resistance and low conductance, while objects made of electrical conductors like metals tend to have very low resistance and high conductance. This relationship is quantified by resistivity or conductivity. The nature of a material is not the only factor in resistance and conductance, however; it also depends on the size and shape of an object because these properties are extensive rather than intens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise Mitigation
Noise control or noise mitigation is a set of strategies to reduce noise pollution or to reduce the impact of that noise, whether outdoors or indoors. Overview The main areas of noise mitigation or abatement are: transportation noise control, architectural design, urban planning through zoning codes, and occupational noise control. Roadway noise and aircraft noise are the most pervasive sources oenvironmental noise Social activities may generate noise levels that consistently affect the health of populations residing in or occupying areas, both indoor and outdoor, near entertainment venues that feature amplified sounds and music that present significant challenges for effective noise mitigation strategies. Multiple techniques have been developed to address interior sound levels, many of which are encouraged by local building codes. In the best case of project designs, planners are encouraged to work with design engineers to examine trade-offs of roadway design and architectural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
