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## 3db Vs 5db Exchange Rate

This is the 3dB exchange rate that most of the world uses. 5dB up to 10GHz and less than 2dB peaking from 16GHz to 24GHz, and less than 3% total. $20 OFF orders over$600. This fall or reduction in gain is known commonly as the roll-off region of the frequency response curve. LED showing level noise exceedances during run. What is considered good DSL line attenuation ? Line attenuation (loss) is a measure of how much the signal has degraded between the DSLAM and the modem. However, their low ra. Noise levels above 140 dB are not considered safe for any period of time, however brief. and an Exchange Rate of 5dB; in this example a 100% DOSE would be received in only 4 hours. However, I've noticed that the large companies seem to be more susceptible to commodity price fluctuations, currency exchange rates, gas prices, etc. Wide dynamic range from 70 to a full 140dB. Some organizations such as OSHA in the U. • Calculates all the popular noise dose parameters. To derive X = 5dB, the sound intensity would have to be more than doubled in this equation. 00 ET or order online 24/7. Refer to the local regulations or standards. Figure 4 Q vs. Exchange rate refers to how the sound energy is averaged over time. BB Healthcare Trust plc is a closed-ended investment company, registered in England and Wales on 7 October 2016. edu is a platform for academics to share research papers. This case study of a educational institution is based on an October 2019 survey of HPE High Performance Computing Solutions customers by TechValidate, a 3rd-party research service. dollar has gained increasing prominence in domestic and international economic policy discussions. To derive X = 5dB, the sound intensity would have to be more than doubled in this equation. But nearly all speakers are in this range, plus or minus 5db. 5dB Frequency weighting 'A' weighting Frequency response 31. Read here for an explanation plus a handy calculator which will convert dB values into watts and vice versa. A 5dB gain antenna radiates more energy toward the horizon compared to the 0, 2 and 3dB antennas to reach radio communication sites that are further apart and less obstructed. International prices may vary due to local duties, taxes, fees and exchange rates. The magnitude of the analog or digital output signal from the microphone with that input stimulus is a measure of its sensitivity. Estimating Exchange Rate Effects on Exports: A Cautionary Note Michael 1'. We invite you to the world of 3D BlockChain value, by giving a real comprehension of its prospect and worthiness!. ; Doswell Royster, Julia. Understanding Noise Exposure Limits: Occupational vs Blogs. 3dB (C or Z weighted), Exchange Rate: Q=3 or Q=5dB exchange rates. The non-zero baseline level was due to water remaining in the diluted peptide solution. 70 - 90dB in 1dB steps. The two exchange rates currently used are the 3 db(A) (NIOSH) and the 5 db(A) (OSHA) exchange rate. 1 ETH to USD, ETH to USD Exchange Rate, ETH to USD Currency Converter. They deliver more hours of dependable use, with less time spent for calibration or repair. Should I use a -3. Dose count 1% to 9999% with Variable exchange rate of 3dB,4dB or 5dB exchange rates 75dB, 80dB, 85dB or 90dB criterion value. Product reviews, live phone support, best price guarantee. Unluckily, you can do nothing about a low attenuation figure, except from moving to a new location closer to the ADSL exchange. Using the decibel scale, every time the sound energy doubles, the measured level increases by 3dB. Other Exchange Rates can be selected (3, 4, 5, or 6dB). As the market leader in noise dosimeters, Quest is committed to offering the most innovative cable-free dosimeter on the market today. The Difference Between OSHA and NIOSH — and How They Work Together December 7, 2016 Love it or hate it, every warehouse manager knows what the Occupational Safety and Health Administration ( OSHA ) does. As you listen to these files, you will notice that the last is quieter than the first, but it is rather less clear to the ear that the second of any pair is quieter than its predecessor. This is the 3dB exchange rate that most of the world uses. Casella Intrinsically Safe Noise Dosimeter Kit dBadge2IS/K5. Estimating Exchange Rate Effects on Exports: A Cautionary Note Michael 1’. A more relevant index is total daily production, since this total will reflect the robot's es-sential characteristics; the advantage of being able to work con-. Wide dynamic range from 70 to a full 140dB. ca The noise exposure limit for a 12-hour shift using an exchange rate of 3dB and limit of 85 dB(A), based on the equal energy rule, is 83. , who authored. Many other nations have already lowered their noise PELs to that level. * Simple operation, including direct read-out of results. The Noise Dose Meter measure the frequency weighted noise exposures and peak sound levels simultaneously. Real-time clock with calendar. Configuration Options. • Calculates the LC-LA value. the relationship of voltage, loudness, power and decibels What a boring title! On the contrary, I think you will find the information contained herein to be both enlightening (maybe even surprising) and certainly valuable. dBadge2Pro dBadge2 Pro Personal Noise Dosimeter with Audio 90. Understanding dB. Currency Exchange in London. Calculates the LC-LA value. For example, the maximum permitted duration for a 100 dB(A) noise exposure in the 3 dB(A) exchange rate is 15 minutes. On a good line, BT generally considers that a 6 dB SNR margin is appropriate to maintain a connection without a significant number of drops or errors. Normally I determine number of taps as I did above and then put in targets of 1 for the passband and 0 for the rejection band in the filter design- I review performance and increase/decrease. Both ooheadsoo and I have built the MBOW1 actually. The 3 dBA exchange rate, the ACGIH recommended criteria, results in statistically significant higher values than the 5dBA exchange rate rec-ommended by OSHA, when noise levels vary from 70 dBA to 120 dBA while measurements are taken. edu is a platform for academics to share research papers. It has dual channels, with channel 1 configurable and channel 2 set to make ISO 3dB measurements. This is the 3dB exchange rate that most of the world uses. If you need advanced statistical analysis of your noise exposure data then the NoisePro™ DLX should be your next noise dosimeter. And you'd want a REALLY nice Amp like the Borderpatrol 300B SE Amp (around $6,000 at current exchange rate). the o/p of the gain rate will be 70% to 100%. Visit our article Chart of ADSL and ADSL2+ speed versus distance for a corresponding chart of downlink connection speed against distance from the exchange. In voltage it may not make not make tons of sense as to why we use (\$\sqrt{2}/2\$), but lets look at an example of what it means in the sense of power. SPECIFICATIONS Standard applied Microphone Display Measurement Ranges Frequency Weightings Time Weightings Exchange Rate Threshold Level Criterion Level Alarm warning indicators Clock Memory Measurement Control Timers Logging storage (results) Stored profile values Storage interval Setup Battery. Available in three models, The Edge offers advanced technology packaged in a cable-free, compact frame for a lighter, more ergonomic way to monitor noise levels. 61 for an exchange rate of 5dB (LOSHA) 20. After all, I spend plenty of my hard earned income locally (local power supplier, local water supplier, local council rates, local taxes). What is dB and frequency? dB and frequency are terms to describe sound level and the number of cycles of a sound wave in one second. Exchange Rate. The dollar’s value gen-erally fell against other currencies. Exchange rate refers to how the sound energy is averaged over time. The Sound Exposure (in physical units) for the measurement duration is known as E (Pa2h). Derive useful insights of your favourite currency contracts from the table below. The 3 dB(A) exchange rate is more stringent. Equal energy rule. dollars, and accordingly, we have not been exposed to foreign currency exchange rate fluctuations related to sales transactions. OSNR for individual test channel It can be noticed that the Q vs. This is because with a 5dB Exchange Rate, a 5dB increase in sound level is considered a doubling of the DOSE. Casella CEL CEL-35X dBadge User Manual • 7 technical specification, 1 specification • Casella CEL Measuring instruments. With the expansion of technology, The Desire to have more TV's through out your house attached to your cable line grows. This paper proposes a Flexible Neural Tree (FNT) model for forecasting three major international. Available in three models, The Edge offers advanced technology packaged in a cable-free, compact frame for a lighter, more ergonomic way to monitor noise levels. The TSI EDGE™4 Dosimeter is an advanced cable-free personal noise meter that features a rechargeable lithium polymer battery and a compact lightweight design. Frequency Weightings 'A' for all RMS measurements 'C' for Peak Sound Pressure. Threshold Level. The 3 dBA exchange rate, the ACGIH recommended criteria, results in statistically significant higher values than the 5dBA exchange rate rec-ommended by OSHA, when noise levels vary from 70 dBA to 120 dBA while measurements are taken. Therefore they are more useful in mountainous and metropolitan areas with tall buildings. Which is the stronger signal and how would it be best to break it down to 4 outputs. Dependance sound levels change factor perceived loudness decibel scale log compare intensities calculate power level formula noise volume doubling loudness volume - logarithm decibel 3 dBSPL 6 dB 10 dB double voltage sound pressure acoustic power loudness sound audio formula relationship decibels dB two times twice as loud louder double distance half by what factor does level decrease increase. A lower noise level means tha. 0, 200, 600 and 600/200 daPa and manual Sweep Accuracy – 10% of nominal rate Maximum limits (in 0. Top selection of 2019 Bluetooth Q1, Consumer Electronics, Earphones & Headphones, Bluetooth Earphones & Headphones, Phone Earphones & Headphones and more for 2019!. User selectable Exchange Rate (3dB, 4dB or 5dB) User selectable Criterion Level (75dB, 80dB, 85dB or 90dB) User selectable Threshold Level (-5dB, -10dB or OFF) Zpeak % Dose Lep'd (Lex) % DOHR (Dose/Hour) Pa2h (Lep'd expressed in Pascals) Exposure Time Lockable Keypad Constructed from tough crack resistance plastic: The GA257L dosemeter also. When your broadband service is first switched on, the target SNR margin is set by the BT exchange equipment at 6 dB. The Noise Dose Meter measure the frequency weighted noise exposures and peak sound levels simultaneously. However, corporations are now reevaluating their risk based on legal cases. exchange rates lower than those specified by OSHA. Dosimeter: Quest EDGE Cable-Free Noise Dosimeters - EG4, EG5. It is the ideal tool to carry out occupational and industrial hygiene noise measurements and provides a unique solution for these applications. Q is the exchange rate in dB, and q = the parameter that determines the exchange rate, where: q = 10 for a 3dB exchange rate q = 13. This requires major advances in aircraft noise reduction at airports, just not to increase the noise exposure due to the increased number of aircraft movements. exchange time was imported into a non-linear least squares routine and fit to the equation, H = H o exp(−kt) + baseline, to define the exchange rate at a given pD. Title: Comparison of daily noise exposures in one workplace based on 3-dB vs 5-dB exchange rates and criteria recommended by the ACGIH versus OSHA. occupational noise from 90 dBA to 85 dBA and to adopt a 3 dB exchange rate for calculating noise dose as a function of exposure time and level. One decibel is of the same order as the Just Noticeable Difference (JND) for sound level. 5db would it make two -7db or would splitting-7db make two -3. Also, antenna gain shoots over the target area and data rates are reduced. 3dB (C or Z weighted), Exchange Rate: Q=3 or Q=5dB exchange rates. Try Prime Measures simultaneously 3dB and 5dB exchange rates. First, the decibel scale is open-ended like that of the Richter scale used for measuring earthquake intensities. This is because with a 5dB Exchange Rate, a 5dB increase in sound level is considered a doubling of the DOSE. (Though the MBOW1 is no longer quite as cheap to build as it once was, because with exchange rates the tweeters have become extremely expensive and there is also a lot of copper used, which has also increased in price. * For 5dB exchange rate instead of 3dB, order the 1805, 2805, 1505, 2505: Click to view a PDF file of our New Sound Level Meter and Vibration Monitor brochure: Various Approvals. The EF-701M interface converts a single channel of standard or TW partyline intercom to four-wire audio, while also converting call signals to RS-422 data (and back). The doseBadge is the original wireless personal noise dosimeter. If the Time Weighting is set to Slow, or a Threshold is set, with any exchange rate (3dB, 4dB or 5dB) the Overall Measurement. Cable Splitters. To derive X = 5dB, the sound intensity would have to be more than doubled in this equation. , who authored. Peak levels up to 143. For example, in the European Union, the EU Physical Agents (Noise) Directive requires the measurement of noise exposure using a 3dB Exchange Rate and recording of LEX,8h and Peak(C), whereas the American OSHA Regulations require the use of a 5dB Exchange Rate, a Slow Time Weighting and an 80dB Threshold. It is the ideal tool to carry out occupational and industrial hygiene noise measurements and provides a unique solution for these applications. 3M Quest SoundPro SE and DL meters include two virtual sound level meters for simultaneous measurements in accordance with regulatory standards. Use a comparison tool like the one above to find the best remortgage deal for you. Criterion Level. Exchange Rate. worked or a peak of > 140 dBC. HHUL TPG Thompson Speedtouch 546v5 DOWN(9. Also if the noise level was say 93dBA, 3dB higher, a 100% DOSE would be accumulated in only 4 hours, The above example is for a dose meter with 3dB Exchange Rate, where a 3dB increase in sound level corresponds to a doubling energy. Dosimeter: Quest EDGE Cable-Free Noise Dosimeters - EG4, EG5. 3dB (C or Z weighted), Exchange Rate: Q=3 or Q=5dB exchange rates Threshold and Criterion: 70-90dB in 1dB steps. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates. The 3 dBA exchange rate, the ACGIH recommended criteria, results in statistically significant higher values than the 5dBA exchange rate rec-ommended by OSHA, when noise levels vary from 70 dBA to 120 dBA while measurements are taken. An alternative to the AMS1000 module from Hypex would be two UcD400HG with HxR and one SMPS1200A400 power supply, totaling$ 489 with current exchange rates. noise dosimeters. An unbiased and informed discussion of many of the more contentious features of wind power and wind farms. All measurements will use the a weighting, slow response, and 5dB exchange rate. Description: Different Receiver Architectures: PCI Express 3. It has dual channels, with channel 1 configurable and channel 2 set to make ISO 3dB measurements. By contrast, the exchange rate defined in the OSHA standard is 5dB (that is, the level must. When the doseBadge is configured to either 4dB or 5dB Exchange Rates, the Overall Measurement Information contains the LAVG, TWA, % Noise Dose and the Estimated % Noise Dose. This case study of a educational institution is based on an October 2019 survey of HPE High Performance Computing Solutions customers by TechValidate, a 3rd-party research service. The Edge eg5 model is a cable-free personal noise dosimeter with Intrinsic Safety approvals from MSHA, SIRA (ATEX), CSA (US and Canada), and Simtars (IECEx) for use in potentially hazardous environments such as mines, petrochemical sites, and manufacturing facilities. To satisfy other regulations around the world, the doseBadge can use an exchange rate of 3dB, 4dB or 5dB. For children, the World Health Organization (WHO) recommends no exposure above 120 dB. 3dB (A) RMS : Frequency Weightings : A, C and Z,Type 2 : Time Weightings : Fast, Slow and Impulse : Exchange Rate : Q=3 or Q=5dB Exchange Rates : Threshold and Criterion : 70-90dB in 1dB Steps : Operating Temperature Range : 0 Degree C - 40 Degree C. By the way HFK is owned by AudioNord Distribution, in Denmark. (Though the MBOW1 is no longer quite as cheap to build as it once was, because with exchange rates the tweeters have become extremely expensive and there is also a lot of copper used, which has also increased in price. For every increase of 3dB in the time-weighted average the measured DOSE would double. Air traffic is growing at a steady rate of to 7% per year in most regions of the world, implying a doubling every 10-25 years. 4-Wire Interface with Call Signal, Matrix-to-Partyline. The lossy link attenuates the forward channel data with an approximate first-order transfer function that has a much lower bandwidth than the data frequency (data frequency, f b, is equal to one-half of the bit rate). - A stakeholder pointed out that there seemed to be general consensus that an 85 dB threshold with a 3 dB exchange rate is a best practice. Price only $110 to get the Xduoo XP-2 bluetooth 5. Any time a TV distribution signal is split, it will encounter insertion loss that will weaken the signals distributed beyond the splitter. The rationale for implementing these changes is clearly stated in a position paper written for ISEA by widely respected hearing conservation expert, Alice Suter, Ph. So the achievable data rate is influenced more by the channel's bandwidth and noise characteristics than the signal bandwidth. vs 5BARz International, Inc. However, stranded center conductors have a little higher loss than solid ones. These two exchange rates, with criterion levels of 85 dB(A) and 90 dB(A), give two different sets of exposure guidelines, as Table 1A and 1B show. The 3 dBA exchange rate, the ACGIH recommended criteria, results in statistically significant higher values than the 5dBA exchange rate rec- ommended by OSHA, when noise levels vary from 70 dBA to 120 dBA while measurements are taken. Hire this kit of 5 Casella dBadge2 Noise Dosemeters and take your noise at work assessments to the next level. What is considered good DSL Noise margin / SNR ? How to disable Windows Vista TCP/IP auto-tuning ? I can't connect to my router's admin interface ? Wireless Repeater / Extender vs. ; Doswell Royster, Julia. The 3M-Quest EDGE 4 is a cable-free personal noise dosimeter that has all the features of the NoisePro DLX. The price of each liquor is based on its demand and it fluctuate every minute. LAeq is always based on an Exchange Rate, or Q, of 3. Calculates all the popular noise dose parameters. I would not be surprised though of the Price of a 'set' of 85/15's were$400 (or more) new which would still be less than the prices I see based on current Exchange rates. The splitter they put has a -7. In other words, if the noise level is kept below 83 dB(A) then, according to equal energy concept, the maximum permissible limit is not exceeded. TES Electrical Electronic Corp. 00 ET or order online 24/7. The effects of 1 MAC pred F6 ranged from enhancement of the responses to low concentrations of GABA (+96 ± 11% at 1 μM, p=0. guidelines are based on a 3dB exchange rate as opposed to the 5dB mandated by OSHA (3) but the use of Slow time weighting and an 80dB threshold remain. Fixed Rate lines are generally 512kbps, 1Mb or 2Mb and these have corresponding sync speeds of 576kbps, 1152kbps and 2272kbps respectively. dBW or decibel-watt is a unit of power in decibel scale, referenced to 1 watt (W). The Edge Personal Noise Dosimeter. I know what db is but i dont know what octave is An octave is a doubling of frequency. Configuration Options. dB for reference 1uV or 1uV. Take Paradigm for example. For example, the National Institute for Occupational Safety and Health (NIOSH) has an 8-hour TWA recommended exposure limit (referred to as a REL) of 85 dBA. Under normal music reproduction conditions the 10A rail fuses are sufficient even in 2Ω. Decibels vs. Find out all of the information about the klipsch product: tower speaker F-10. The National Institute of Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH) have both called for an 85 dBA exposure limit. It is the ideal tool to carry out occupational and industrial hygiene noise measurements and provides a unique solution for these applications. dollars, and accordingly, we have not been exposed to foreign currency exchange rate fluctuations related to sales transactions. 4-Wire Interface with Call Signal, Matrix-to-Partyline. Noise-induced hearing loss (NIHL) is 100% preventable; however, once acquired, it is permanent and irreversible [NIOSH 1998]. BB Healthcare Trust plc is a closed-ended investment company, registered in England and Wales on 7 October 2016. Remember what I said earlier about the relationship between power and 3db; 3db doubles or halves the power. Try Prime Measures simultaneously 3dB and 5dB exchange rates. The doseBadge is the original wireless personal noise dosimeter. Using OSHA's exchange rate, what must you do if the work environment increases by 5dB? cut exposure time in half If I double my exposure time from 8 to 16 hours, by NIOSH standards, my noise intensity can be. TES Electrical Electronic Corp. Cable Splitters. The dollar’s value gen-erally fell against other currencies. In voltage it may not make not make tons of sense as to why we use (\$\sqrt{2}/2\$), but lets look at an example of what it means in the sense of power. Product reviews, live phone support, best price guarantee. Noise Intensity Level and Duration of Exposure The risk of noise to hearing is based upon two factors: noise intensity level (loudness) and the duration of exposure. 37-2015-00025796-CU-BC-CTL (County of San Diego). dBadge2Pro dBadge2 Pro Personal Noise Dosimeter with Audio 90. Back to the Home Page [. OSNR in 4 shows the same type of relationship as in Figure 2. A lower noise level means tha. $20 OFF orders over$600. 5dB up to 10GHz and less than 2dB peaking from 16GHz to 24GHz, and less than 3% total. 3dB, 4dB, 5dB or 6dB. Derive useful insights of your favourite currency contracts from the table below. Currency Exchange in London. edu is a platform for academics to share research papers. The lossy link attenuates the forward channel data with an approximate first-order transfer function that has a much lower bandwidth than the data frequency (data frequency, f b, is equal to one-half of the bit rate). Exchange Rates for Intermittent and Fluctuating Occupational Noise: A Systematic Review of Studies of Human Permanent Threshold Shift, Ear Hear 35, 86–96. OSNR in 4 shows the same type of relationship as in Figure 2. When the doseBadge is configured to either 4dB or 5dB Exchange Rates, the Overall Measurement Information contains the LAVG, TWA, % Noise Dose and the Estimated % Noise Dose. For any regulations not covered you can select Customer and configure your own settings. The impact of using a 3-dB vs 5-dB exchange rate on the predicted employee's 8-h equivalent A-weighted sound-pressure level in three different types of industrial work environments Authors: Royster, Larry H. I think the price drop has more to do with exchange rates. Prices are indicative only and may vary by country, with changes to the cost of raw materials and exchange rates. The Edge eg5 model is a cable-free personal noise dosimeter with Intrinsic Safety approvals from MSHA, SIRA (ATEX), CSA (US and Canada), and Simtars (IECEx) for use in potentially hazardous environments such as mines, petrochemical sites, and manufacturing facilities. The Model 22 doseBadge is compact, extremely robust and lightweight No cables or controls, reducing the risk of damage, misuse or tampering Everything you need supplied in one user-friendly system package. SVR rates are relatively high, so it's worth looking for a new mortgage deal. rate of production of a manual system with the rate of produc-tion of an automated system then the automated system can ap-pear to have little or no advantage. I removed everything else from the splitter, but not sure what type of splitter to use (-3. Again, you may see different prices if you look on the Official PRS website under Accessories for the region you are living in. EE 323 - Filters. Search the history of over 384 billion web pages on the Internet. com 1‐ Reflected Power (%) = 100 * Γ. Cable Splitters. Refer to the local regulations or standards. Decibels Power-ratio. * Simple operation, including direct read-out of results. Start studying AUDIOLOGY FINAL. Features---The Noise Dose Meter measure the frequency weighted noise exposures and peak sound levels simultaneously. An avid vinyl collector and coffee addict, I can often be found at a workbench tinkering with a faulty electronic device, tweaking a turntable to extract the last bit of detail from those tiny grooves in the plastic stuff, or relaxing in front of the hi-fi with a good album. The maximum, minimum and time-weighted average noise levels are stored for all measurements with. dBadge2Pro dBadge2 Pro Personal Noise Dosimeter with Audio 90. When the doseBadge is configured to either 4dB or 5dB Exchange Rates, the Overall Measurement Information contains the LAVG, TWA, % Noise Dose and the Estimated % Noise Dose. Other Exchange Rates can be selected (3, 4, 5, or 6dB). Could you detail how you made the comparison? Billy, the -3dB/15hz data on the Hsu comes from Keele. OSNR for individual test channel It can be noticed that the Q vs. It has dual channels, with channel 1 configurable and channel 2 set to make ISO 3dB measurements. The Edge eg5 model is a cable-free personal noise dosimeter with Intrinsic Safety approvals from MSHA, SIRA (ATEX), CSA (US and Canada), and Simtars (IECEx) for use in potentially hazardous environments such as mines, petrochemical sites, and manufacturing facilities. 3dB peak), measure the Slow, Fast, Impulse and Peak responses simultaneously, and calculate the time-weighted average noise level with the 3, 4 and 5 dB exchange rates in every run. The speaker levels are set to achieve two goals: (1) make each speaker play at the same level as the others and (2) make the system play at film reference level when the volume control is set to reference (0 dB when using the relative scale setting). erage (TWA) calculated results may vary significantly depending upon the exchange rate used. The National Institute of Occupational Safety and Health (NIOSH) and the American Conference of Governmental Industrial Hygienists (ACGIH) have both called for an 85 dBA exposure limit. Attenuator Imports Data under HS 85367000 | India Import of HS 85367000, Indian Importers of Attenuator in India, Indian Import of HS 85367000 Attenuator, Attenuator Buyers, Attenuator Shipment Data, HS 85367000 Shipment Data, Major Countries exporting Attenuator, Monthly Trends, Major Ports. Configuration Options. Overall i liked this place. When the doseBadge is configured to either 4dB or 5dB Exchange Rates, the Overall Measurement Information contains the LAVG, TWA, % Noise Dose and the Estimated % Noise Dose. dollars based upon Bloomberg's conversion rates. NIOSH uses 85 db(A) with a 3db exchange rate and OSHA uses 90 bd(A) with a 5 db exchange rate to determine their maximum. The CR:110A doseBadge can be easily configured to meet any of these requirements. Single measurement range from 54 to 140 dB which covers all levels required by OSHA, ACGIH and other national and international standards. APPENDIX D Noise Model Output Griffith Park Performing Arts Center Project Initial Study/MND December 2013. 70 - 90dB in 1dB steps. Many other nations have already lowered their noise PELs to that level. 5dB may be added to the permissible exposure level every time the exposure duration is cut in half. For 3dB Exchange Rate: LAeq, LEX,8h, LAE, % Dose, Exposure (Pa2h), Estimated % Dose, Estimated Exposure (Pa2h) For 4dB & 5dB Exchange Rates: LAVG, TWA, % Dose, Estimated % Dose. The non-zero baseline level was due to water remaining in the diluted peptide solution. The Hypex will yield 240w per channel into 8 ohms whereas the AMS1000 will yield 170w per channel. The 3 dBA exchange rate, the ACGIH recommended criteria, results in statistically significant higher values than the 5dBA exchange rate rec- ommended by OSHA, when noise levels vary from 70 dBA to 120 dBA while measurements are taken. Posted on January 28, 2015. TES 660 Micro Noise Dosimeter (Badge Type) - - Amazon. A 5dB gain antenna radiates more energy toward the horizon compared to the 0, 2 and 3dB antennas to reach radio communication sites that are further apart and less obstructed. The Company's registered office is Mermaid House, 2 Puddle Dock, London EC4V 3DB. A 2dB or 3dB gain antenna is the compromise in suburban and general settings. Top selection of 2019 Bluetooth Q1, Consumer Electronics, Earphones & Headphones, Bluetooth Earphones & Headphones, Phone Earphones & Headphones and more for 2019!. They used to own NAD, before Lenbrook (Canada) acquired it. RMS Range 70dB to 140dB RMS Weighting A or C RMS Time Response Fast or Slow Frequency Weighting A, C, Z. This mixer is optimized for differential IF output, and a parallel 2kΩ resistor is needed for IF output matching. L) INCE the abandonment offixed exchange rates in the early 1970s, the value of the U. I think the price drop has more to do with exchange rates. The Safety and Environmental Data Logging Sound System is designed for Noise at Work and Environmental measurements and features the Sonus Logging meter. Exchange Rate: 5 MAX SPL: 115 Peak SPL: 140 Specifications: ANSI S1. 3dB, 4dB, 5dB or 6dB. Calculating OSHA Employee Permissible Exposure Limit for Noise. * For 5dB exchange rate instead of 3dB, order the 1805, 2805, 1505, 2505: Click to view a PDF file of our New Sound Level Meter and Vibration Monitor brochure: Various Approvals. Got to say it went better than I expected and cruises along at 145 kph quite happily and it averaged 9. Threshold Level. 4200 | Fax 408. And you'd want a REALLY nice Amp like the Borderpatrol 300B SE Amp (around $6,000 at current exchange rate). Peak Measurement Range: 90. Microphone sensitivity is typically measured with a 1 kHz sine wave at a 94 dB sound pressure level (SPL), or 1 pascal (Pa) pressure. The noise exposure limit for a 12-hour shift using an exchange rate of 3dB and limit of 85 dB(A), based on the equal energy rule, is 83. Use the Post Office Branch Finder tool to find our where your nearest branch is and what services are available at your local branch. It has dual channels, with channel 1 configurable and channel 2 set to make ISO 3dB measurements. * Simple operation, including direct read-out of results. I would not be surprised though of the Price of a 'set' of 85/15's were$400 (or more) new which would still be less than the prices I see based on current Exchange rates. This is because with a 5dB Exchange Rate, a 5dB increase in sound level is considered a doubling of the DOSE. By contrast, the exchange rate defined in the OSHA standard is 5dB (that is, the level must. e-Book - Microstrip Antenna Design. Exchange Rates for Intermittent and Fluctuating Occupational Noise: A Systematic Review of Studies of Human Permanent Threshold Shift, Ear Hear 35, 86–96. * Simple operation, including direct read-out of results. 4-Wire Interface with Call Signal, Matrix-to-Partyline. The Sonus L model features parameters for measuring a wide range of applications. There are some real problems with wind turbines and there are a number of alleged problems that are unfairly used by opponents of wind power to discredit the technology. The Edge Personal Noise Dosimeter. The Difference Between OSHA and NIOSH — and How They Work Together December 7, 2016 Love it or hate it, every warehouse manager knows what the Occupational Safety and Health Administration ( OSHA ) does. Find out all of the information about the klipsch product: tower speaker F-10. Exchange Rate. *Prices are pre-tax. In this figure, we get the optimum value of ‘n’ out of ‘K’ CRs. dB Noise Reduction frequently asked questions are well written and informative. For 3dB Exchange Rate: L Aeq, L EX,8h, L AE, % Dose, Exposure (Pa 2h) Estimated % Dose, Estimated Exposure (Pa 2h) For 4dB & 5dB Exchange Rates (and con gurations with Time Weighting or Threshold): L AVG, TWA, % Dose, Estimated % Dose 1 Minute Time History of: L Aeq (3dB) or L AVG (4dB or 5dB) Peak(C) Level Battery Level Channel 2 Measurement. Take Paradigm for example. In other words, if the noise level is kept below 83 dB(A) then, according to equal energy concept, the maximum permissible limit is not exceeded. and an Exchange Rate of 5dB; in this example a 100% DOSE would be received in only 4 hours. Get same day shipping on Studio Monitors - Active like the KRK V Series 4 White Noise 8-In Powered Studio Monitor at PSSL. Therefore, they are more useful in mountainous and metropolitan areas with tall buildings. If you live in Canadait could be best to stay with a brand like Paradigm with the current exchange rates. It is the ideal tool to carry out occupational and industrial hygiene noise measurements and provides a unique solution for these applications. 5db cable splitter for my digital cable? The higher channels on my digital cable are very pixelated. From graph we conclude that for low threshold value with low SNR, the required number of CR’s is more. The Noise Dose Meter measure the frequency weighted noise exposures and peak sound levels simultaneously. Refer to the local regulations or standards. Independent Exchange Rates: 3dB, 4dB or 5dB for each dosimeter Independent Criterion Levels: from 70dB to 90dB in 1dB increments Measurement Settings. The doseBadge Industrial version of this popular noise dosimeter is housed in a metal case for tough industrial environments. However, their low ra. THD+N (BW=20kHz): Blue 8Ω (350W), Red 4Ω (600W) Measurements was not performed in 2Ω because rail fuses (10A) will surely blow. A dose meter with 5dB Exchange Rate is also, available where the sound must increase by 5dB to double the dose as required to meet noise legislation in some countries. Other Exchange Rates can be selected (3, 4, 5, or 6dB). Lightweight and small size. ; Doswell Royster, Julia. Wide dynamic range from 70 to a full 140dB.


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# Maximum principle

1. Aug 20, 2010

### aa1174

can you please help me give an example of an illustration of the maximum principle of the heat equation (using partial differential equations)

thank you..

2. Aug 20, 2010

### kof9595995

em..how about a trivial example that the heat equation reduces to the Laplace equation, and as we know every solution to Laplace equation satisfies maximum principle.

3. Aug 22, 2010

### aa1174

thank you. how about other examples?

4. Aug 22, 2010

### aq1q

do you want a real-life example or an actual math problem that uses the maximum principle?

5. Aug 22, 2010

### aa1174

an actual math problem.. thank you..

6. Aug 22, 2010

### aq1q

Check it out: http://www.math.ucsb.edu/~grigoryan/124A/lecs/lec8.pdf

It's great. It has the proof of the maximum principle (its weaker form) in detail. I think you should find it useful.
Honestly, there are plenty of problems online and in textbooks (you can use google books). Here is one I found in mine:

Consider the diffusion equation $$u_t = u_{xx}$$ in (0 < x < 1, 0 < t < $$\infty$$) with u(0, t) =u(1, t) =0 and u(x, 0) =4x(1 - x).

(a) Show that 0 < u(x,t) < 1 for all t>0 and 0<x< 1.

(b) Show that u(x, t) = u(1 - x, t) for all t $$\geq$$ 0 and 0 $$\leq$$ X $$\leq$$ 1.

(c) Use the energy method to show that $$\int u^2 dx$$ is a strictly decreasing function of t.

parts a and b emphasize more on the maximum principle.

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# SMSPrint causes error in FE code

I am using Mathematica 12.0, AceGen version 7.101. I have not detected this problem when I was using older versions of both, but I've had no need to use the SMSPrint[] command for quite some time, so I don't know if this problem is recent or not. Using SMSPrint[exp1,exp2,"Output" -> {"File", "test.out"}] in the element code, causes the element .dll not to be generated in AceFem. This is the error I get:

Compiler's messages: TestElement.c: In function 'SKR': TestElement.c:4087:1: error: expected declaration or statement at end of input }; ^

By not using the option "Output"->{"File", "test.out"}, the SMSPrint[exp1,exp2] works fine, but I want to be able to print the results in a file, not inside the Mathematica notebook.

Another problem is the use of a new line \n in the expression inside the SMSPrint function. For some reason the element code is not even generated if new line is used. This is the error I get when I try to write the element code, using SMSWrite[]:

SMC::Warning: Cannot split program line.(Sigma=',(double)(v[1382]),(double)(v[1383]),(double)(v[1384]),(double)(v[1385]),(double)(v[1386]),(double)(v[1387]),(double)(v[1388]),(double)(v[1389])); ).

For example, using the option \t inside the SMSPrint[] works fine.

Is there any fix to this, or am I doing something wrong? I have tested this on 2 different basic element codes, but have not tried using an older version of software.

Edit: I was able to recreate the error on an element code from AceShare found here http://symech.fgg.uni-lj.si/MainLibraryV11/SE/7/SEMSS1ASHYANSP6DFiSVenant.html By changing the "Mode" from "Optimal+" to "Debug", and inserting the SMSPrint[] function (that must include a newline \n) somewhere in the code, the same error ("Cannot split program line....") can be observed and the element is not generated.

• Could you provide a MWE of your problem? Apr 8, 2020 at 9:09
• I have tried this also on the element code from AceShare. The code is found here symech.fgg.uni-lj.si/MainLibraryV11/SE/7/… By changing the "Mode" from "Optimal+" to "Debug", and inserting the SMSPrint[] function (that must include a newline \n) somewhere in the code, the same error ("Cannot split program line....") can be observed and the element is not generated. Apr 8, 2020 at 11:02


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YOCTO PROJECT

A SSH server can be a very useful thing to have in a embedded Linux build. It enables things such as scp (secure copy, allowing you to copy files between the embedded device to a development computer over the internet).

You should be able to add a SSH server by adding the following line to your build/conf/local.conf file.

EXTRA_IMAGE_FEATURES += "ssh-server-openssh"

## Add Python To A Build

IMAGE_INSTALL_append = " python-core"

## Add Boost To A Build

IMAGE_INSTALL_append = " boost"

When adding boost, it is work recreating the SDK so that you have the available libraries for cross-compiling.

IMAGE_INSTALL += " valgrind"


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# Real Analysis/Limits

 Real Analysis Limits

## Definition

Recall that a function from a set X to a set Y is a mapping $f: X \rightarrow Y$ such that f(x) is a unique element of Y for every $x\in X$. In analysis, we tend to talk about functions from subsets $A \subseteq \mathbb{R}$ to $\mathbb{R}$.

The definition for the limit of a function is much the same as the definition for a sequence. In fact, as we will see later, it is possible to define functional limits in terms of sequential limits. For the moment, however, let us just give the definition:

Given a subset $A \subset \mathbb{R}$ and a function $f:A\rightarrow \mathbb{R}$, we say $\lim_{x \rightarrow c}f(x) = L$ if $\forall \epsilon > 0: \exists \delta: 0<|x-c|<\delta \implies |f(x)-L|<\epsilon$

The requirement $|x-c|>0$ is somewhat technical. It is an expression of the idea that the behavior of a function near a point shouldn't be affected by its behavior at the point. Thus f(x) need not be defined at c to have a limit there.

This definition gives a lot of people a lot of trouble, so it is best to spend some time puzzling it out, working examples, etc. One way to conceptualize the definition is this: $\lim_{x \rightarrow c}f(x) = L$ means that we can make f(x) as close as we like to L by making x close to c.

We can also define what it means for a function to diverge to infinity, and what it means for a function to have a limit at infinity:

• We say that $\lim_{x \rightarrow c}f(x) = \infty$ if $\forall M>0: \exists \delta: 0<|x-c|<\delta \implies f(x)>M$.
• We say that $\lim_{x \rightarrow c}f(x) = -\infty$ if $\forall M>0: \exists \delta: 0<|x-c|<\delta \implies f(x)<-M$
• We say that $\lim_{x \rightarrow \infty}f(x) = L$ if $\forall \epsilon > 0: \exists M: x > M \implies |f(x)-L|<\epsilon$.
• We say that $\lim_{x \rightarrow -\infty}f(x) = L$ if $\forall \epsilon > 0: \exists M: x < -M \implies |f(x)-L|<\epsilon$.

As an exercise, see if you can define what it means for a function to have limit $\infty$ as $x \rightarrow \infty$.

## Sequential Limits

We might just as well have given the following definition of the limit:

Given a subset $A \subset \mathbb{R}$ and a function $f:A\rightarrow \mathbb{R}$, we say $\lim_{x \rightarrow c}f(x) = L$ if $\forall (x_n)_{n=1}^{\infty}$ such that $x_n \not= c, \lim_{n \rightarrow \infty}(x_n) = c$, and $\lim_{n \rightarrow \infty}(f(x_n)) = L$

Note that the requirement $x_n \not= c$ corresponds with the requirement $|x - c| > 0$.

As an exercise to test your understanding, prove that these two definitions are equivelant. Note that taking the contrapositive gives a good criterion for determining whether or not a function diverges:

If $\exists (x_n), (y_n): (x_n)\rightarrow c, (y_n)\rightarrow c$, and $\lim_{n \rightarrow \infty}(f(x_n)) \not= \lim_{n \rightarrow \infty}(f(y_n))$, then $\lim_{x \rightarrow c}f(x)$ does not exist.

We will be using this formulation extensively in the examples.

## Algebraic Operations/Ordering Theorems

By applying the corresponding theorems for sequential limits, we find that functional limits are unique, that they preserve algebraic operations and ordering, and that a corresponding "Squeeze Theorem" holds. If $\lim_{x \rightarrow c}f(x) = L$, and $\lim_{x \rightarrow c}g(x) = M$, then:

• $\lim_{x \rightarrow c} af(x) = aL$
• $\lim_{x \rightarrow c} f(x) + g(x) = L + M$
• $\lim_{x \rightarrow c}f(x)g(x) = LM$
• $\lim_{x \rightarrow c}\frac{f(x)}{g(x)} = \frac{L}{M}$, assuming

$M$ and $g(x)$ are non-zero.

• If $\exists \delta: f(x) > g(x) \forall x \in A$, then $L > M$.
• $L=M, f(x) \leq h(x) \leq g(x) \implies \lim_{x \rightarrow c}h(x) = L$
• If L = 0 and h(x) is bounded, then $\lim_{x \rightarrow c}f(x)h(x) = 0$.

### Examples

We'll be giving many more examples in the section on continuity. Unfortunately, it is hard to properly define many of the most elementary functions without appealing to derivatives, integrals, and power series, so many of the examples here may seem a bit contrived. We'll start with a relatively nice function and move on to some nastier, unintuitive ones, with the goal being some kind of intuition about what can go right and wrong with limits.

• Let $f(x) = \left \{ \begin{matrix} 1 & \mbox{if }x = 0 \\ 0 & \mbox{if }x \not= 0 \\ \end{matrix} \right.$. Then $\lim_{x \rightarrow 0} f(x) = 0$.

• Let $f(x) = \left \{ \begin{matrix} 0 & \mbox{if }x\leq 0 \\ 1 & \mbox{if }x > 0 \\ \end{matrix} \right.$. Then $\lim_{x \rightarrow 0} f(x)$ does not exist.

Consider the sequences $(x_n) = (\frac{1}{n}), (y_n = (\frac{-1}{n})$. Each converges to zero, but $(f(x_n)) = 1$ and $(f(y_n)) = 0$, and these have different limits as $n \rightarrow \infty$. Thus the limit does not exist.

The next example is often given as a demonstration of just how nasty functions can get. It is not continuous at any point of its domain.

• Let $f(x) = \left \{ \begin{matrix} 1 & \mbox{if }x \in \mathbb{Q} \\ 0 & \mbox{if }x \in \mathbb{R} \setminus \mathbb{Q} \\ \end{matrix} \right.$. Then $\lim_{x \rightarrow c} f(x)$ does not exist for any $c \in \mathbb{R}$.

Given $x \in R$, let $x_n$ be any rational number in the interval $(\frac{-1}{n},\frac{1}{n})$, and let $y_n$ be any irrational number in the same interval ($x_n$ and $y_n$ are gauranteed to exist by density of the rationals and irrationals). Given any $\epsilon > 0, |x_n - 0| < \frac{1}{n}$ and $|y_n - 0| < \frac{1}{n}$, so $(x_n),(y_n) \rightarrow 0$. However, (f(x_n)) = 1 and (f(y_n)) = 0, so their limits are 1 and 0. Since these are not equal, $\lim_{y\rightarrow x} f(y)$ does not exist.

Now we finally get to a limit that actually exists. Don't get too excited, though. The function is still extremely nasty (nastier than the previous two, perhaps), and the fact that it has a limit everywhere is one of its nastier aspects.

• Let $f(x) = \left \{ \begin{matrix} \frac{1}{q} & \mbox{if }x = \frac{p}{q} \in \mathbb{Q}\\ 0 & \mbox{if }x \in \mathbb{R} \setminus \mathbb{Q} \\ \end{matrix} \right.$. Then $\lim_{x \rightarrow c} f(x) = 0$ for all $c \in \mathbb{R}$.

The idea is to show that the denominators of the rational numbers near f(x) are arbitrarily large. Given $\epsilon > 0$, let $\frac{1}{N} < \epsilon$, and let $S = {\frac{p}{q} \in Q: 0<|\frac{p}{q} - c|< 1, q \leq N}$. This is a finite set, since the numerators and the denominators are bounded and can therefore only take on a finite number of values. Thus, let $\frac{p}{q}$ be the element of S such that $|\frac{p}{q} - c|$ is minimized, and let $\delta = |\frac{p}{q} - c| = \delta$. Then $\forall 0<|x-c|<\delta: |f(x)-0| = |f(x)| = 0 < \epsilon$(if x is irrational) or $|f(x)-0|= |f(x)| < \frac{1}{N} < \epsilon$. Thus $\lim_{x \rightarrow c} f(x) = 0$.

## Definition on an Arbitrary Metric Space

Let $(X,d_1)$, and $(Y,d_2)$ be metric spaces. And let $f:X \to Y$

The limit as $x \in X$ approaches $a \in X$ of $f$ is equal to $L \in Y$ if $\forall \epsilon > 0 \text{ }\exists \delta \text{ such that if } 0

This is denoted $\lim_{x \to a} f = L$


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# Posts published in “Math”

Implement pow(xn), which calculates x raised to the power n (xn).

Example 1:

Input: 2.00000, 10
Output: 1024.00000

Example 2:

Input: 2.10000, 3
Output: 9.26100

Example 3:

Input: 2.00000, -2
Output: 0.25000
Explanation: 2-2 = 1/22 = 1/4 = 0.25

Note:

• -100.0 < x < 100.0
• n is a 32-bit signed integer, within the range [−231, 231 − 1]

## Solution: Recursion

square x and cut n in half.
if n is negative, compute 1.0 / pow(x, |n|)

pow(x, n) := pow(x * x, n / 2) * (x if n % 2 else 1)pow(x, 0) := 1
Example:pow(x, 5) = pow(x^2, 2) * x           = pow(x^4, 1) * x           = pow(x^8, 0) * x^4 * x          = 1 * x^4 * x = x^5

Time complexity: O(logn)
Space complexity: O(logn)

## C++

Given two binary strings, return their sum (also a binary string).

The input strings are both non-empty and contains only characters 1 or 0.

Example 1:

Input: a = "11", b = "1"
Output: "100"

Example 2:

Input: a = "1010", b = "1011"
Output: "10101"

Solution: Big integer

Time complexity: O(n)
Space complexity: O(n)

## C++

Given a non-empty array of digits representing a non-negative integer, plus one to the integer.

The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.

You may assume the integer does not contain any leading zero, except the number 0 itself.

Example 1:

Input: [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.

Example 2:

Input: [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.

Solution: Big Integer

Process from right to left (lest significant to most signification). Use carry to indicate whether need +1 for next digit or not.

Time complexity: O(n)
Space complexity: O(n)

## c++

In a forest, each rabbit has some color. Some subset of rabbits (possibly all of them) tell you how many other rabbits have the same color as them. Those answers are placed in an array.

Return the minimum number of rabbits that could be in the forest.

Examples:
Input: answers = [1, 1, 2]
Output: 5
Explanation:
The two rabbits that answered "1" could both be the same color, say red.
The rabbit than answered "2" can't be red or the answers would be inconsistent.
Say the rabbit that answered "2" was blue.
Then there should be 2 other blue rabbits in the forest that didn't answer into the array.
The smallest possible number of rabbits in the forest is therefore 5: 3 that answered plus 2 that didn't.

Input: answers = [10, 10, 10]
Output: 11

Output: 0

Note:

1. answers will have length at most 1000.
2. Each answers[i] will be an integer in the range [0, 999].

## Solution: Math

Say there n rabbits answered x.
if n <= x: they can have the same color
if n > x: they must be divided into groups, each group has x + 1 rabbits, and there are at least ceil(n / (x+1)) groups.
So there will be ceil(n / (x + 1)) * (x + 1) rabbits. This expression can be expressed as (n + x) / (x + 1) * (x + 1) in programming languages. (n + x) // (x + 1) * (x + 1) for Python3.

## Python3

Given two strings S and T, each of which represents a non-negative rational number, return True if and only if they represent the same number. The strings may use parentheses to denote the repeating part of the rational number.

In general a rational number can be represented using up to three parts: an integer part, a non-repeating part, and a repeating part. The number will be represented in one of the following three ways:

• <IntegerPart> (e.g. 0, 12, 123)
• <IntegerPart><.><NonRepeatingPart>  (e.g. 0.5, 1., 2.12, 2.0001)
• <IntegerPart><.><NonRepeatingPart><(><RepeatingPart><)> (e.g. 0.1(6), 0.9(9), 0.00(1212))

The repeating portion of a decimal expansion is conventionally denoted within a pair of round brackets.  For example:

1 / 6 = 0.16666666… = 0.1(6) = 0.1666(6) = 0.166(66)

Both 0.1(6) or 0.1666(6) or 0.166(66) are correct representations of 1 / 6.

Example 1:

Input: S = "0.(52)", T = "0.5(25)"
Output: true
Explanation:
Because "0.(52)" represents 0.52525252..., and "0.5(25)" represents 0.52525252525..... , the strings represent the same number.

Example 2:

Input: S = "0.1666(6)", T = "0.166(66)"
Output: true

Example 3:

Input: S = "0.9(9)", T = "1."
Output: true
Explanation:
"0.9(9)" represents 0.999999999... repeated forever, which equals 1.  [See this link for an explanation.]
"1." represents the number 1, which is formed correctly: (IntegerPart) = "1" and (NonRepeatingPart) = "".

Note:

1. Each part consists only of digits.
2. The <IntegerPart> will not begin with 2 or more zeros.  (There is no other restriction on the digits of each part.)
3. 1 <= <IntegerPart>.length <= 4
4. 0 <= <NonRepeatingPart>.length <= 4
5. 1 <= <RepeatingPart>.length <= 4

## Solution1: Expend the string

Extend the string to 16+ more digits and covert it to double.

0.9(9) => 0.99999999999999
0.(52) => 0.525252525252525
0.5(25) => 0.5252525252525

## C++

Mission News Theme by Compete Themes.


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## Rotating black hole with a probe string in Horndeski Gravity

22 May 2020  ·  F. F. Santos ·

In this work, we present the effect of a probe string on Horndeski's gravity on the complexity of the black hole according to the CA conjecture (Complexity equals action). In our system we consider a rotating black hole in ($2+1$)-spacetime... We consider the effect of the string moving in this spacetime geometry of the black hole BTZ. Thus, for the double description, we have the insertion of a fundamental string in the bulk of spacetime. The effect of this string is given by the Nambu-Goto term. Analyzing the term Nambu-Goto, we can analyze the time of development of this system according to the parameters of Horndeski's gravity. In ours we show some interesting properties of complexity for this severity. read more

PDF Abstract

# Code Add Remove Mark official

No code implementations yet. Submit your code now

# Categories

High Energy Physics - Theory General Relativity and Quantum Cosmology


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# Blog

January 7, 2021

## echo pb 2620 vs stihl

Transitive Relation - Concept - Examples with step by step explanation. De nition 2. Loosely speaking, it is the set of all elements that can be reached from a, repeatedly using relation … R2 is certainly contained in the transitive closure, but they are not necessarily equal. transitive closure can be a bit more problematic. It can be shown that the transitive closure of a relation R on A which is a finite set is union of iteration R on itself |A| times. The transitive closure of R is the relation Rt on A that satis es the following three properties: 1. TRANSITIVE RELATION. In this article, we will begin our discussion by briefly explaining about transitive closure and the Floyd Warshall Algorithm. Connectivity Relation A.K.A. For a relation R in set AReflexiveRelation is reflexiveIf (a, a) ∈ R for every a ∈ ASymmetricRelation is symmetric,If (a, b) ∈ R, then (b, a) ∈ RTransitiveRelation is transitive,If (a, b) ∈ R & (b, c) ∈ R, then (a, c) ∈ RIf relation is reflexive, symmetric and transitive,it is anequivalence relation 1. R =, R ↔, R +, and R * are called the reflexive closure, the symmetric closure, the transitive closure, and the reflexive transitive closure of R respectively. 3) The time complexity of computing the transitive closure of a binary relation on a set of n elements is known to be: a) O(n) b) O(nLogn) c) O(n^(3/2)) d) O(n^3) Answer (d) In mathematics, the transitive closure of a binary relation R on a set X is the smallest transitive relation on X that contains R. We will also see the application of Floyd Warshall in determining the transitive closure of a given graph. Transitive Closures Let R be a relation on a set A. The program calculates transitive closure of a relation represented as an adjacency matrix. The last item in the proposition permits us to call R * the transitive reflexive closure of R as well (there is no difference to the order of taking closures). Transitive closure. For calculating transitive closure it uses Warshall's algorithm. It is not enough to ﬁnd R R = R2. For transitive relations, we see that ~ and ~* are the same. Warshall’s Algorithm: Transitive Closure • Computes the transitive closure of a relation Algorithm Warshall Let us consider the set A as given below. Notice that in order for a … The transitive closure of a binary relation $$R$$ on a set $$A$$ is the smallest transitive relation $$t\left( R \right)$$ on $$A$$ containing $$R.$$ The transitive closure is more complex than the reflexive or symmetric closures. A = {a, b, c} Let R be a transitive relation defined on the set A. Deﬁning the transitive closure requires some additional concepts. 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Uncategorized


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# Heated MOSFET with LED strip

I am trying to toggle the power on a 24V LED strip using a IRFZ44N MOSFET. I am able to power the LED strip and vary the current using different PWM duty cycles, but the MOSFET gets really hot, especially when the lights are "dimmed", i.e. 0 < duty-cycle < 100. With duty-cycle = 0 there are no heating issues though.

The LED strip is rather power consuming, 24W/m, and I'm utilizing 4m so i figured a 4A power supply would suffice. The idea is to toggle the voltage, ~10V, on the T3 MOSFET gate by regulating the current at the base of T1 and T2. To my help is a Raspberry Pi 4B, using 3.3V GPIO, the 12V input is 1A

I am not an EE and apologize if there is anything unclear about the above schematic, would be happy to elaborate.

I found a similar post here on SE, which made me suspect the PWM frequency and T3 input voltage: I've tried many different PWM frequencies, from 1Hz to 10KHz, and also measured the voltage on the T3 gate, which according to my multi-meter is around 12v, 10V+ should be enough from what i understand. I didn't quite get the points they made about capacitance, but i have tried to lower the resistance on R4, which seems to delay the heating issue, but not fix it.


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Effect Of Overall Treatment Time

As always, Hall is an invaluable reference, particularly the chapter on Time, Dose and Fractionation in Radiotherapy (Chapter 22). This entry is mainly based on that chapter.

# Overall Treatment Time and Dose

The first observed effects with regards to time and dose were that as treatment time increased, the dose required to achieve a similar effect (the isoeffective dose also increased.

## Isoeffect Curves

Isoeffect curves were first published in 1944 by Strandquist. They showed the effect of treatment time on the the dose required for certain effects.

## Nominal Standard Dose

The nominal standard dose was the first widely used equation developed to determine biological effect based on the number of fractions and the overall treatment time. It was developed by Ellis in the 1960s from data on skin reactions, and was frequently used until supplanted by the more accurate linear quadratic and alpha beta models. It is given by the following formula, where T is treatment time in days and N is the number of fractions.

(1)
\begin{align} \text{Dose}=\text{NSD}.\text{T}^{0.11}.\text{N}^{0.24} \end{align}

And

(2)
\begin{align} \text{NSD}=\frac{\text{Dose}}{\text{T}^{0.11}.\text{N}^{0.24}} \end{align}

The NSD (nominal standard dose) constant represented the tolerance of skin. It was also applied to other organs and connective tissue. If the calculated NSD value for a fractionated treatment was less than the tolerance NSD value, then it would be 'safe' to increase the amount of treatment until tolerance was reached.

### Partial Tolerance (PT)

The partial tolerance was introduced by Ellis to counter the inability of the NSD model to adjust for changes in treatment regimen (from 5 to 3 fractions per week) or for gaps in treatment. The partial tolerance of a treatment course x (PTx) was given by:

(3)
\begin{align} PT_x=\frac{N_x}{N_{T_x}}.\text{NSD} \end{align}

Where Nx represented the number of fractions given in a treatment, and NT was the number of fractions required to reach the tolerance of the tissue. The NSD value represented the tolerance of the tissue in general.

The various partial tolerances of a treatment could then be added up:

(4)
$$PT_{tot}=PT_1 + PT_2 + ... + PT_n$$

It was also realised that gaps in treatment increased the tolerance of tissues. This was accounted for by another equation which used the rest period R to adjust the partial tolerance:

(5)
\begin{align} PT_{x_{\text{after rest}}}=PT_x(\frac{T}{T-R})^{0.11} \end{align}

### Problems with the NSD model

I haven't finished going into the NSD model, but as you can see it becomes very complicated with altered treatment regimes. It was also inaccurate due to reliance on acute skin toxicity data. Finally, it also assumes repopulation is linear, whereas human data shows repopulation does not become a significant factor for about 4 weeks. It was also very cumbersome and difficult to use when treatments became more complicated.

The Cumulative Radiation Effect was proposed by Kirk et al in 1971. It was an improvement on the NSD, by substituting factors related to dose per fraction ($d=\frac{D}{N}$) and interval per fraction ($x=\frac{T}{N}$). The subsequent equation eliminated the total dose (D) and treatment time (T).

(6)
\begin{align} CRE = \frac{dN^{0.65}}{x^{0.11}} \end{align}

The CRE functioned in a similar way to the NSD - if the calculated CRE for a treatment was less than the tolerance CRE, then the treatment would be 'safe'. If different treatment schedules were used, the CRE values could be added to give the total CRE for a treatment. Unlike the NSD model, the CRE model took variations in treatment schedule into account and did not require the partial tolerance concept.

The CRE model suffered from the same problems as the NSD with regards to reliance on skin toxicity and problems with repopulation calculations. It would be overturned by the linear quadratic equation and alpha/beta models.

## Proliferation of Normal Tissues

The two major problems with the early formulae such as the NSD and CRE were:

• Proliferation of normal tissues does not occur linearly as time increases
• Early responding and late responding tissues undergo proliferation at different times

### Sigmoid Increase in Normal Tissue Proliferation

Studies on mouse skin have shown that proliferation does not occur until about 12 days after starting fractionation. Beyond this point, it rises rapidly, requiring an extra 1.3 Gy per day to reach the same biological effect.

This sigmoid curve explains why the NSD and CRE models are inaccurate, as they assume the above line to be linear.

### Differences in tissue types

Different tissues proliferate at different times after exposure to ionising radiation.

Late responding tissues tend to proliferate much later following treatment, usually after therapy has ceased, whereas early reacting tissues (and some tumours) begin proliferating during the course of treatment.
Hall sums this up well:

Prolonging overall treatment time, within the normal radiotherapy range:

• Significantly reduces early treatment related effects
• Has minimal effect on late treatment effects

## Summary of Overall Treatment Time

• Treatment time was observed by Strandquist in the 1940s to increase the dose required for the same effect
• Initial modeling of this effect was done with NSD and CER equations, but these were inaccurate due to insufficient data to model them on
• Early reacting tissues begin proliferation after a short time interval. This means that overall treatment time has a major effect on the effects seen.
• Late reacting tissues begin proliferation after treatment has been completed (for most treatments). This means that overall treatment time has minimal effects on the effects seen.


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# The Flat Earth Society!

## Recommended Posts

I noticed that the site is receiving quite a lot of traffic for the past few days from a site called theflatearthsociety.org ... apparently, they do still exist (isn't that cute?) and they're discussing my "the earth is not flat" post!

Check it out here: http://theflatearthsociety.org/forum/index.php?topic=23120.msg480940

Check out their reasoning, too.. I was curious to see if I should, perhaps, correct myself or be more specific, but apparently their problems with what they call the "REers" ("Round Earthers"?) is not about the logic.

Go figure.

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#### Popular Posts

Most of them don't believe in Flat Earth (FE), but it also looks like a lot of them really enjoy just confounding people that don't realize how easy it is to counter argue - even against something as

while some of them are merely practicing debate skills, there is a core of people who really do still believe the earth is flat. there are also those who believe the earth is hollw and there is a gian

I hate to be the one to tell all of you that the Earth isn't round. It's spherical.

It's bendy light I tell thee!!!

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.. but apparently their problems with what they call the "REers" ("Round Earthers"?) is not about the logic.

:eek:The Earth is round!?! Preposterous!!!

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It's bendy light I tell thee!!!

its not "bendy light" its curved space caused by gravity over 1,000`s of miles of flatness.

and I thought you understood fiziks!

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pfft your all wrong isn't it obvious the surface of the earth is the inside of a giant cosmic egg with the sun(yoke) at the centre and when that chicken starts growing then we're really fscked

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• 4 months later...

And the stars are just other cities on the far side of the Egg. right?

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From the looks of that link, it seems that most of the flat earthers don't believe that the earth is flat, but are being devil's advocate for fun. It is a good logical exercise, to see whether the evidence can be explained while maintaining that the earth is flat.

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Most of them don't believe in Flat Earth (FE), but it also looks like a lot of them really enjoy just confounding people that don't realize how easy it is to counter argue - even against something as obvious as the fact that the Earth is round.

It's not always through "high brow debating tactics" and honestly, my favorite thread I've ever read there was on plate tectonics, but devolved into "Dinosaurs could have built boats" where, I am pretty sure the debate ended when the proponent of "fossil records prove Pangaea" had to excuse himself to prevent an aneurism.

The few threads that really challenge "Flat Earth Theory" in a simple, hard to "wiggle out of" way tend to get a little attention at first due to misconception by "FEers" and, then quickly die without any posts to challenge the "Round Earth" arguments.

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• 1 month later...

i figured out how to destroy them, sign up, become a mod, then say you went into space and saw the earth round

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i figured out how to destroy them, sign up, become a mod, then say you went into space and saw the earth round

how little you know about this kind of person. you could take them up into space themselves and show them and they would still not accept the earth was round.

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• 8 months later...

i think its funny how their logo looks like a globe.

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I started a thread on this months ago. Most people don't realize that these people are simply practicing their debate skills. It makes for good fun, certainly more so than watching cable television.

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while some of them are merely practicing debate skills, there is a core of people who really do still believe the earth is flat. there are also those who believe the earth is hollw and there is a giant 1000km wide hole at the north pole to the center that people have somehow missed all these years.

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• 2 weeks later...

Hasn't there been research on the human brain and how it interprets visual data? Such as... well, I don't know... the 3D being interpreted as 2D data by the brain but later processed as 3D?

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• 4 weeks later...

Of course the world is flat. How else would people make maps that lie flat on the wall?

Irrefutable evidence!

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I can almost understand believing the earth was flat by crazy theories alone... but shouldn't it have ended when we actually got into space and took pictures of earth... you can debate forever on theories because of the void of absolute evidence (in a way) but once we got into space and saw it, seems like the game would end right about there.

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• 2 months later...

Of course the Earth is flat!

...economically speaking, that is

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• 2 weeks later...

...and they're discussing my "the earth is not flat" post!

Incidentally, your number 9 is not a good argument, since the Earth could be an infinite plane, so the force would be downwards everywhere, not directed towards the centre (there would be no centre).

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Incidentally, your number 9 is not a good argument, since the Earth could be an infinite plane, so the force would be downwards everywhere, not directed towards the centre (there would be no centre).

But if it would be infinite, you wouldn't be seeing an edge. We do see an edge (and quite close to us, relatively, in the form of the horizon) and so either the Earth has a limited size or it's curved...

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Do flat earthers even believe in gravity? What if they think it's not masses attracting, but just a universal "down" force? Or maybe the Earth is just perpetually accelerating uniformly up?

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But if it would be infinite, you wouldn't be seeing an edge. We do see an edge (and quite close to us, relatively, in the form of the horizon) and so either the Earth has a limited size or it's curved...

I'm fairly certain that, given that the horizon is only 30 miles away or so, most flat earthers have a different explanation for horizons than "that's where the Earth ends."

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I'm fairly certain that, given that the horizon is only 30 miles away or so, most flat earthers have a different explanation for horizons than "that's where the Earth ends."

I'll be happy to hear it and examine it.

As it turns out, *most* of the known flat-earth "hypothesis" claims that the Earth is a flat disk. With an end to it. Why does the horizon look like it's around 30 miles away? .... uhhhhhhhhh...... becauseeee...we........ uhhh... need glasses...?

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As it turns out, *most* of the known flat-earth "hypothesis" claims that the Earth is a flat disk. With an end to it.

Why does the horizon look like it's around 30 miles away? .... uhhhhhhhhh...... becauseeee...we........ uhhh... need glasses...?

There's also the option of a not-so-flat plane, with a what-do-ya-call-it, spherical cap type shape.

But they also have very strange ideas about light: 'bendy light' as they call it. If light travelled really slowly and was affected by gravity (or an upwardly mobile earth) in a much greater sense than it actually is - so more like a bullet than a photon - then once 'shot' from far away at a reasonable height it'd eventually hit the ground.

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But if it would be infinite, you wouldn't be seeing an edge. We do see an edge (and quite close to us, relatively, in the form of the horizon) and so either the Earth has a limited size or it's curved...

We see an edge... but that observation is caused by mass hallucination.

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I'd rather try to explain quantum mechanics to a chicken than talk to a flat earther. They are so deluded that the only way to get anything into their brain is with an ice pick

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# Famous Theorems of Mathematics/Number Theory/Fermat's Little Theorem

## Statement

If p is a rational prime, for all integers a ≠ 0,

$a^{p-1}\equiv 1 \mod{p}$

## Proofs

There are many proofs of Fermat's Little Theorem.

Proof 1 (Bijection)

Define a function $f(x)=ax$ (mod p). Let S={1,2,...,p-1} and T=f(S)={a,2a,...,(p-1)a}. We claim that these two sets are identical mod p.

Since all integers not equal to 0 have inverses mod p, for any integer m with 1≤m<p, $f(a^{-1}m)=m$. Then $f$ is surjective.

In addition, if $f(x)= f(y)$, then $ax\equiv ay$ and $a^{-1}ax\equiv x\equiv y\equiv a^{-1}ay$. Then $f$ is injective, and is bijective between S and T.

Then, mod p, the product of all of the elements of S will be equal to the product of elements of T, meaning that

$\prod_{k=1}^{p-1} k \equiv \prod_{k=1}^{p-1} ak \pmod p$ and that
$\prod_{k=1}^{p-1}k \equiv a^{p-1}\prod_{k=1}^{p-1} k \pmod p$.

Then

$a^{p-1}\equiv 1 \mod{p}$.