This Paper Explains the Calculation and Adjustment Method of Frequency Divider in Detail

Do you know that the reason why the speaker has such excellent bass and treble sound quality effect is entirely due to the audio frequency divider in the speaker equipment. Without this small speaker frequency divider, the speaker cannot have excellent sound quality effect at all. This paper mainly leads you to understand the calculation and adjustment of the frequency divider. First, let's understand the principle of the frequency divider and the frequency division point. Second, let's understand the calculation sequence and adjustment method of the frequency divider in detail.

Introduction to frequency divider

The frequency divider is to distinguish the sound signals of different frequency bands, amplify them respectively, and then send them to the speakers of the corresponding frequency band for playback. Electronic frequency division processing is needed in high-quality sound playback.

The frequency divider is a circuit device in the speaker, which is used to separate the input analog audio signal into different parts such as treble, midrange and bass, and then send them to the corresponding high, midrange and bass speaker units for playback. The reason for this is that no single speaker can perfectly replay all frequency bands of sound.

The frequency divider is the "brain" in the speaker, which is very important to the sound quality. The music signal output by the power amplifier must be processed by the over filter element in the frequency divider to let the signal of specific frequency of each unit pass through. Only by scientifically, reasonably and rigorously designing the frequency divider of the speaker, can we effectively modify the different characteristics of the speaker unit, optimize the combination, make each unit develop its strengths and avoid its weaknesses, give full play to their due potential, make the frequency response of each frequency band smooth and the audio-visual phase accurate, and make the music played by high, medium and bass clear, in harmony, bright, comfortable Broad and natural sound quality effect.

In a speaker system, people call the box, frequency division circuit and speaker unit the three major parts of the speaker system, and the frequency divider is the "brain" in the speaker. The frequency division circuit plays an extremely important role in whether the speaker system can restore electroacoustic signals with high quality. Especially in the medium and high frequency parts, the role of frequency division circuit is more obvious.

Principle of frequency divider

From the perspective of circuit structure, the frequency divider is essentially an LC filter network composed of capacitors and inductors. The high frequency channel is a high pass filter, which only allows high-frequency signals to pass through and prevents low-frequency signals; The bass channel is just the opposite. It only allows the bass to pass through and blocks the high-frequency signal; The midrange channel is a band-pass filter. Except that the frequency between two frequency division points can pass through, the high-frequency component and low-frequency component will be blocked. In the actual frequency divider, sometimes in order to balance the sensitivity difference between high and low frequency units, attenuation resistance should be added; In addition, some frequency dividers also add an impedance compensation network composed of resistance and capacitance, which aims to make the impedance curve of the speaker psychological flat, so as to facilitate the driving of the power amplifier.

Since the current speakers almost all adopt the design mode of multi unit frequency division and playback, there must be a device that can divide the full band music signal sent by the power amplifier into treble, bass output or treble, midrange and bass output as required, so as to be connected with the corresponding speaker unit. The frequency divider is such a device. If the full band signal is directly sent to the high, medium and low frequency units without distribution, the "redundant signal" outside the frequency response range of the unit will have an adverse impact on the signal restoration in the normal frequency band, and may even damage the high and medium tone units.

Introduction to frequency division points

Frequency division point refers to the dividing point between high pass, band-pass and low-pass filters of frequency divider. It is commonly expressed in frequency, and the unit is hertz. There is only one frequency division point for high and low frequency division speakers, and there are two frequency division points for high, medium and low frequency division speakers. The frequency division points shall be determined according to the frequency characteristics and power distribution of each frequency band speaker unit or speaker.

The frequency division point is usually defined as the frequency at the intersection of the responses of two frequency dividers (generally composed of an LPF and an HPF), which may be the frequency division point on the electrical characteristics of two electronic frequency dividers (driven or active), or the frequency division point on two acoustic filters. Any horn unit is essentially a filter, each with its inherent high-pass and low-pass filters, as well as its inherent cut-off frequency, slope and network type.

The overall acoustic frequency division point of a system depends on the mathematical combination of the frequency response of the electronic filter and the horn unit in the system. When an electronic filter is added to an acoustic filter system, their frequency response will be superimposed to form a new response curve.

The difference in sound level / sensitivity between two different units and the phase lag of high-frequency devices are obvious. The high-frequency part is likely to be fixed on the horn of a long throat, resulting in delay relative to the low-frequency speaker. In order to better reproduce the signal of the system, the newly developed frequency divider is required to smooth the frequency response curve.

Calculation and adjustment method of frequency divider

1. Calculation order

At present, the calculation method introduced in most materials is to take the rated impedance of the loudspeaker as the fixed value to obtain the LC value of the frequency division frequency, and then adjust the parameters during the sound test. Practice has proved that the error between the calculation results of this method and the final adjustment parameters is too large, because its impedance will increase with the increase of frequency. Although the parallel RC series resonant circuit at both ends of the speaker can stabilize its impedance near the rated impedance, there is no special instrument under amateur conditions. The more frequency division elements, the greater the phase shift, so these two methods are not desirable. Facts show that taking the impedance of the loudspeaker at the frequency division point as the fixed value, the accuracy of obtaining the LC value of the frequency division is high. Taking the common double bass inverter box as an example, this paper introduces the calculation method of two frequency division network with 12dB / oct-6db landing point crossing. According to the parameters of high and low woofer, the frequency division point is 3kHz.

Measure the treble DC resistance ro = 7.6 Ω and the inductance L = 0.52mh with a digital multimeter.

Measure the parallel DC resistance ro = 3.7 Ω and the parallel inductance L = 0.57mh of the double bass with a digital multimeter,

2. Adjustment method

Install the loudspeaker into the speaker box, and select the large 4P junction box and double line sound splitting method. Weld the speaker and the wiring in the junction box. The frequency divider adopts external lap welding, which is convenient for adjustment.

The attached table shows the Hugo gold disc (1) measured by digital frequency meter

Signal frequency of section 17-45. Although there is a certain error, it is enough to be used as an adjusting frequency divider.

Under normal listening volume, when playing the test signal, it is found that the sound pressure at the frequency division of 2.5KHz 4kHz is high. Connect the treble of one speaker in the same phase, and repeatedly compare the sound pressure at the frequency division point and other points with the balance knob of the combined power amplifier. There is no obvious difference. The experience of making frequency divider for many times in the past shows that this is not a large deviation of calculated value. The main reason is that the frequency response curve of loudspeaker can not be obtained under business conditions. The frequency division point falls on the peak point of high and low bass, including the influence of the loudspeaker installed in the box on the frequency response curve. Should we adjust the treble frequency division network or the bass frequency division network now?

According to the parameters of the loudspeaker, the treble sensitivity is 91dB and the mid bass sensitivity is 89dB. When two subwoofers are used in parallel, the impedance is 4 Ω, which reduces the treble sensitivity. In addition, during the audition, the sound pressure of the treble attenuated at 2.5KHz can be heard at locm from the speaker, but it can not be heard at 2KHz. Because its low frequency response reaches 1.5khz, it shows that the frequency division network is correct. The medium and low frequency speakers still have high sound pressure at 4kHz. The above two points indicate that the low-pass network should be adjusted.

Based on the principle of easy before difficult, try to gradually replace C2 with large capacity.

When its capacity is 15 μ F, the frequency signal of the medium and low frequency loudspeaker at 4kHz can not be heard. At the same time, the sound pressure near 3.2khz is also properly attenuated. The parameters of LC element of frequency divider are shown in the attached figure.

3. Phase problem

If you pay attention, you can find that in the two frequency division network published in the newspaper, most of the treble is connected in reverse phase, and a few are connected in phase. According to the calculation method introduced in this paper, the identification of in-phase or inverse connection is mainly at the cross position of high and low frequency division frequency. If the sound pressure at the intersection is small during in-phase connection and increases during reverse phase connection, reverse phase connection shall be adopted. In this way, the phase distortion is minimized. If the synthesized sound pressure is high, the LC value of the frequency division network can be adjusted accordingly, and vice versa. Therefore, we should not arbitrarily think that the treble should be reversed wiring, but draw a conclusion after audition and comparison. For the frequency division circuit in this paper, after repeated comparison of near listening and far listening for many times, because there is no obvious difference, it is finally drawn by the common high pitch inverse connection method.

This Paper Explains the Calculation and Adjustment Method of Frequency Divider in Detail 1

Bellum omnium contra
This Paper Analyzes the Basic Knowledge of WiFi Module in Detail
This Paper Analyzes the Basic Knowledge of WiFi Module in Detail
The following is the total knowledge of WiFi modules compiled by Skylab, hoping to help you!1. What is the SDK of WiFi module?SDK is the English abbreviation of the software development kit (full name: software development kit) of WiFi module. It is generally a collection of development tools used by some software engineers to establish application software for specific software packages, software frameworks, hardware platforms, operating systems, etc.2. What is the driver of the WiFi module?A driver is a small piece of code added to the operating system that contains information about the hardware device. With this information, the computer can communicate with the device. The driver is a configuration file written by the hardware manufacturer according to the operating system. It can be said that without the driver, the hardware in the computer cannot work.For the WiFi module, this hardware can be used as the WiFi module of the slave device. At present, the WiFi module of the slave device of Skylab can provide drivers. The supported systems include window, Linux and Android.3. What is the network port of WiFi module?The network port of WiFi module should be from two aspects,(1) On hardware:Network interface refers to various interfaces of network equipment. The network interfaces we are using today are Ethernet interfaces.Common Ethernet interface types include RJ-45 interface, RJ-11 interface, SC optical fiber interface, FDDI interface, AUI interface, BNC interface and console interface.(2) Software:Network ports are divided into Wan ports and LAN portsWAN port is used to connect the external network (public network), or the equipment of broadband operators.LAN ports (1, 2, 3 and 4) are used to connect devices in the intranet (local area network), mainly to connect computers, switches, printers and other devices.4. What is the IP address of the WiFi module?IP is the abbreviation of English Internet protocol, which means "protocol for interconnection between networks", that is, a protocol designed for communication between computer networks.IP address is a 32-bit binary number, which is usually divided into four "8-bit binary numbers" (that is, 4 bytes).5. What is routing?Routing refers to the process that a router receives a packet from one interface, orients it according to the destination address of the packet and forwards it to another interface.The routing algorithm fills the routing table according to a lot of information. The destination / next hop address pair tells the router that the best way to reach the destination is to send the packet to the router representing "next hop". When the router receives a packet, it checks its destination address and tries to associate this address with its "next hop".6. What is the default gateway?The IP address of a directly reachable router. Configure the default gateway to create a default path in the IP routing table. A host can have multiple gateways. The default gateway means that if a host cannot find an available gateway, it will send the data packet to the default specified gateway, which will process the data packet.For example, the default gateway of Skylab's WiFi module is generally Enter in the address bar of the browser to enter the WiFi module configuration page. On the configuration page, you can set and change the working mode, language and other items of the WiFi module. When the WiFi module is in apclient working mode, there will be two default gateways.7. What is a LAN?LAN refers to a computer group interconnected by multiple computers in a certain area. LAN can realize the functions of file management, application software sharing, printer sharing, schedule within the working group, e-mail and fax communication services. LAN is a closed type, which can be composed of two computers in the office or thousands of computers in a company.8. What is DHCP?DHCP (Dynamic Host Configuration Protocol) is a LAN network protocol that works using UDP protocol. Automatically assign IP addresses to internal networks or network service providers, and give them to users or internal network administrators as a means of central management of all computers. For example, all WiFi modules of Skylab can support DHCP server.According to the DHCP address pool, each device connected to the module will be automatically assigned an IP address.9. TCP / UDP data transmission protocolTCP (transmission control protocol) is a connection oriented, reliable and byte stream based transport layer communication protocol.The process of TCP three handshakes is as follows:The client sends syn (SEQ = x) message to the server and enters syn_ Send status.The server receives a syn message, responds to a syn (SEQ = y) ack (ACK = x 1) message, and enters the syn_recv state.The client receives the syn message from the server, responds to an ACK (ACK = y 1) message, and enters the established state.TCP handshakes three times to establish a connection and four times to disconnect(1) When host a completes the data transmission, set the control bit fin to 1 and make a request to stop the TCP connection(2) Host B responds to fin after receiving it, confirms that the TCP connection in this direction will be closed, and sets ack to 1(3) The B end puts forward the closing request in the opposite direction and sets fin to 1(4) Host a confirms the request of host B, sets ack to 1, and the two-way shutdown endsFrom the three handshakes and four disconnects of TCP, it can be seen that TCP uses the connection oriented communication mode, which greatly improves the reliability of data communication and makes the sending data endIt interacts with the receiver before formal data transmission, which lays a reliable foundation for formal data transmission.The full name of UDP protocol is user datagram protocol. In the network, it is used to process packets like TCP protocol. It is a connectionless protocol.Before transmitting data, the source and terminal do not establish a connection. When it wants to transmit, it simply grabs the data from the application and throws it to the network as soon as possible. At the sender, the speed of UDP transmitting data is only limited by the speed of data generated by the application, the capacity of the computer and the transmission bandwidthDifferences between TCP and UDP:1. Based on connection and no connection;2. Requirements for system resources (more TCP and less UDP);3. UDP program structure is relatively simple;4. Stream mode and datagram mode;5. TCP guarantees data correctness, UDP may lose packets, TCP guarantees data order, and UDP does not.Well, the above is a basic theoretical knowledge of WiFi module compiled by Skylab. I hope it will be helpful to engineers engaged in WiFi module application development!About Skylab:Shenzhen Tiangong measurement and Control Technology Co., Ltd. (Skylab) , is a professional WiFi module manufacturer in China. It began to enter the field of wireless modules in 2002 with profound experience. The WiFi modules launched now include serial port WiFi module, AP / routing WiFi module, high-power UAV WiFi module, USB interface camera module, Gigabit WiFi module, 2.4/5g dual band WiFi module, etc. for more details, you can visit Tiangong measurement and control or Alibaba store
The Working Principle and Application Method of I2C Bus Are Analyzed in Detail
The Working Principle and Application Method of I2C Bus Are Analyzed in Detail
Hello everyone, through the previous study, we have understood and familiar with the use and learning methods of ICD2 simulation burner and enhanced pic experimental board, learned how to use single chip microcomputer to control light-emitting tube, relay, buzzer, key, nixie tube, RS232 serial port, stepping motor, temperature sensor and other resources, and realized the ease of use and learning of the learning board, After reading the previous examples, you must be very excited and have a sense of achievement when your experiment is successful! Now let's strike while the iron is hot and take a step up. Let's learn the working principle and use method of I2C bus, so that we can store some data we want to save in the nonvolatile memory of I2C bus to realize the function of power-off holding. For example, you set a password, but it will not be reset after the device is powered off, We can write the password data in the nonvolatile memory. For example, the reading of the range meter of the car is continuously accumulated, which can be realized by continuously accessing the I2C memory.1、 I2C bus featuresI2C bus is the master-slave structure, MCU is the master device and memory is the slave device. A bus can have multiple slave devices (or multiple master structures). SDA and SCL of I2C bus are bidirectional, open gate structure, and positive power supply is connected through pull-up resistance. During data transmission, the data on SDA line must remain stable in the high-level cycle of the clock. The high or low level state of the data line can be changed only when the clock signal of the SCL line is low, as shown in Fig. 1.Figure 1 validity provisions of data bitsWhen the SCL line is a high level, switching the SDA line from high level to low level indicates the starting condition; When SCL is high, the SDA line switches from low level to high level, indicating the stop condition, as shown in Fig. 2.Figure 2 start and stop signalsEach byte sent to the SDA line must be 8 bits.Multiple bytes can be transferred from high to low. Each byte must be followed by a response bit (ACK). The response clock pulse is generated by the host. The master releases the SDA line, and the slave pulls the SDA line low and remains stable during the high level of the clock pulse. As shown in Figure 3. When the host receives data, it must send a signal to the slave to end the transmission after receiving the last data byte. This signal is realized by the "non response" of the host to the slave. Then, the slave releases the SDA line to allow the host to generate a termination or repeat start signal.Figure 3 byte format and response2、 Data frame format(1) The master sends data to the slave, and the transmission direction of the data does not change during the transmission process, as shown in Figure 4.Figure 4 sending data from master to slaveNote: shaded part: indicates that the host sends data to the slave; Unshaded part: indicates that the host reads data from the slave.A: Indicates a response;: Indicates a non response. S: Start signal; P: Termination signal.(2) The host reads data from the slave immediately after the first byte, as shown in Figure 5.Figure 5 the master reads the slave immediately after the first byte(3) Composite format, as shown in Figure 6. When the transmission changes direction, the starting condition and slave address will be repeated, but the R / W-bit is reversed. If the host receiver sends a stop or repeat start signal, it should have sent a non response signal ().Figure 6 composite formatAs can be seen from the above format, regardless of the transmission mode, the start signal, end signal and address are sent by the host (shaded part in the figure), the transmission direction of data bytes is specified by the direction bit in the addressing byte, and the transmission of each byte must have a response bit (a or b).Next, the enhanced pic experimental board is programmed through the 24C02 example, and its hardware schematic diagram is shown in Figure 7. U7 is the 24C02 chip on the experimental board, SDA is connected with RB5 port of MCU, SCL is connected with RB4 port of MCU, seven segment nixie tubes D5, D7 and D8 form the display unit, and the data of font code is sent through RC port, The display chip selection signal of each nixie tube is controlled by different RA ports.Fig. 7 Schematic diagram of reading / writing AT24C series memoryCreate a new project in MPLAB ide software, add source code, select chip model and set configuration bit at the same time. The chip model used in our experiment is PIC16F877A.The program code is as follows, and the program flow chart is shown in Figure 8.3、 Software flow chartFigure 8 I2C bus read / write data flow chart4、 Software code/**********//*Target device: PIC16F877A*//*Crystal oscillator: 4.0mhz*//*Compilation environment: MPLAB v7.51*//**********//**********Include header file**********/#include/**********Data definition**********/#define address 0xa#define nop() asm("nop")#define OP_ READ 0xa1//Device address and read operation#define OP_ WRITE 0xa0//Device address and write operation/**********Port definition**********/#define SCL RB4#define SDA RB5#define SCLIO TRISB4#define SDAIO TRISB5/**********Common cathode led segment code table**********/const char table[]=0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0x88,0x83,0xC6,0xA1,0x86,0x8E;/**********Function: delay subroutine**********/void delay()int i;for(i=0;i;/**********Function: start signal**********/void start()SDA=1;nop();SCL=1;nop();nop();nop();nop();nop();SDA=0;nop();nop();nop();nop();nop();SCL=0;nop();nop();/**********Function: stop signal**********/void stop()SDA=0;nop();SCL=1;nop();nop();nop();nop();nop();SDA=1;nop();nop();nop();nop();/**********Function: read dataExit parameter: read_ data**********/unsigned char shin()unsigned char i,read_data;for(i=0;i nop();nop();nop();SCL=1;nop();nop();read_data《=1;if(SDA == 1)read_data=read_data1;nop();SCL=0;return(read_data);/**********Function: write data to EEPROMEntry parameter: write_dataExit parameter: ack_bit**********/bit shout(unsigned char write_data)unsigned char i;unsigned char ack_bit;for(i = 0; i if(write_data&0x80)SDA=1;elseSDA=0;nop();SCL = 1;nop();nop();nop();nop();nop();SCL = 0;nop();write_data 《= 1;nop();nop();SDA = 1;nop();nop();SCL = 1;nop();nop();nop();Ack_bit = SDA; / / read the responseSCL = 0;nop();nop();return ack_bit;//Return at24cxx reply bit/**********Function function: write data to the specified addressEntry parameters: addr, write_data**********/void write_byte(unsigned char addr,unsigned char write_data)start();shout(OP_WRITE);shout(addr);SDAIO = 0;//SDA should be set to output before writing datashout(write_data);stop();delay();/**********Function function: read data to the specified addressEntry parameter: random_addrExit parameters: read_data**********/unsigned char read_random(unsignedchar random_addr) unsigned char read_data;start();shout(OP_WRITE);shout(random_addr);start();shout(OP_READ);SDAIO = 1;//SDA should be set as input before reading dataread_data = shin();stop();return(read_data);/**********Function function: display subroutineEntry parameters: K**********/void display(unsigned char k)TRISA=0X00;//Set port a as all outputsPORTC=table[k/1000];//Display thousandsPORTA=0xEF;delay();PORTC=table[k/100%10];//Display hundredsPORTA=0xDF;delay();PORTC = table [k/ 10%10] ;//Display ten digitsPORTA=0xFB;delay();Portc = table [k%10]; / / display bitsPORTA=0xF7;delay();/**********Function: main program**********/void main()unsigned char eepromdata;TRISB=0X00;OPTION&=(1《7);//Set the internal pull-up resistance of Rb port to be effectiveTRISC=0X00;PORTB=0X00;PORTC=0xff;TRISA=0X00;eepromdata=0;write_byte(0x01,0x55);//Write data of 0x55 (85) to 0x01 addressdelay();write_byte(0x02,0xaa);//Write data of 0XAA (170) to 0x02 addressdelay();eepromdata=read_random(0x02);//Read the data in one of the addresses to verifywhile(1)display(eepromdata);After programming, burn the compiled hex code into the single chip microcomputer chip through the ICD2 simulation burner, power on and run. In the main program, write "0x55" at 0x01 address and "0XAA" at 0x02 address, and then read out the value of 0x02 address in the while cycle, that is, the "0x55" we wrote before. After reading out, it is displayed on the nixie tube, and we can see the nixie tube display "170", that is, the corresponding decimal number of "0XAA".As a beginner, readers must have some questions about some sentences. You can see the notes in the program, and analyze the 24C series IC data manual combined with the source program.
Your Family Names and Details?
Your Family Names and Details?
Your family names and details?G-Carina Quinn, sporty but girly, blonde curly hair and green eyes G/G-Hanaley Lyra- dark brown hair, smart, quiet Hadley Mylee-dark brown hair, blue eyes, smart, artsy B-Chase Jackson-blonde hair, blue eyes, sporty OR my families tradition is to have SAS initials, so if I keep my last name... G-Skye Alina G/G-Summer Andrea Sienna Ava B-Sawyer Aaron— — — — — —Is it legal? (Read details)?It is illegal for persons under the age of 21 to purchase, own, rent, steal, borrow hand gun pistols. this is a Federal Statute(Law)— — — — — —DETAIL internationallyThe journal is read in more than 80 countries and is published in three different languages: DETAIL in a bilingual (German-English) edition with an online translation supplement in French and Italian; 10 issues a year (2008) DETAIL in English (the entire journal translated into English; 6 issues a year) DETAIL in Chinese (6 issues a year)— — — — — —Look in the details part for the question.?Obviously it is a Doppler effect problem :->)— — — — — —Would you be leery of this (details)?Definately my friend, see it for what it's worth. They are a wolf in sheep's clothing. You would be better off selling through the classifieds. Every Christian is either a heretic, or a hypocrite!— — — — — —Family Problems. ( Alot of details)?First of all, you should not lie to your mother if you think she really is paying more attention to your brother. An autistic child requires constant stimulation, and that means people have to be with him. I am sure your mother does not mean to slight her other children. But, if that is the effect, she needs to be told so that she can work on it. How would you like it if someone would not tell you that you were doing something to upset them, but then got madder and madder and told everyone about it??? TELL YOUR MOTHER! Secondly, you need someone to blow off some steam with. If you do not have a counselor, maybe you can see a pastor or a teacher. Please seek out someone you can lay some of this frustration on.— — — — — —Accuracy and detail of GreenDespite the fact that Abwehr intelligence-gathering in Ireland had not begun until mid-1939, Green was thorough in detail. This can probably be attributed to the intelligence-gathering of German civilians based in Ireland during the 1930s. That the plan for Green was completed days after being ordered is a testament to the planning staff in collating the data. Hitler's hope of a dtente or non-aggression pact of some kind with the British, whom he considered the "natural allies" of Nazi Germany, led to him disallowing Abwehr intelligence-gathering in Britain during the run-up to the war in 1936-1938. Even when intelligence-gathering was attempted following the fall of France it was mostly disastrous (see Operation Lobster I and Operation Seagull). As Sea Lion was postponed and eventually shelved following the launching of Operation Barbarossa, the planning staff working on it issued two reprints, adding detail as they went. Detail in GreenThe full briefing package for Green runs to five volumes, each devoted to a particular area of military interest. A good example of the detail is a seventy five-page booklet titled "Militrgeographische Angaben ber Irland" ("Military Geographical data on Ireland"). This booklet described the frontier, size, historical background, industry, transport infrastructure, vegetation, climate, and weather of the island. It also included seventeen pages of detailed sketches of 233 cities, towns, and villages, complete with a lexicon. 120 photos accompanied the booklet; annexes contained street maps of twenty-five cities and towns, including street names and addresses of garage owners. A second print of the plan in October 1941 added 332 photographs of the Irish countryside and coastline, mostly tourist photos, which were used to reference highly accurate Ordnance Survey maps. There were also details on spring tides, geological formations and possible routes German troops could take off projected invasion beaches. Another addendum included in the further reprinting of the plan in 1942 by the OKL (Luftwaffe High Command), titled "Ksten-Beschreibung des Irischen Freistaates (Irland)" ("Coastal description of the Irish Free State"), contained high-altitude aerial photographs of the areas in question, some taken from 30,000 feet, with houses and trees visible. Despite this attention to detail, and the improvements in the volume of data with each reprinting, a lot of the data was out of date or incomplete. For example, the Galway-Clifden railway is described as being operational, but it had closed in 1935. Ireland was also described as perfectly suited to military operations because of its "excellent network of roads", and details on population centres such as Derry and Belfast were accurate but lacked information on British troop concentrations based in these cities. On the other hand, the Ardnacrusha power station on the lower Shannon was entirely detailed in the plan, thanks to the help of the German firm Siemens, which had built it prior to the war.
Six Points for Attention in the Installation and Maintenance of Agrometeorological Stations Are Intr
Six Points for Attention in the Installation and Maintenance of Agrometeorological Stations Are Intr
The development of Agrometeorological monitoring provides a basic guarantee for agricultural production. With the wide use of Agrometeorological stations and the advantages of advanced information technology, it realizes the efficient collection, transmission and processing of meteorological data, which not only greatly improves the collection efficiency of meteorological parameters, but also faces the problem of installation and maintenance. The installation and maintenance of Agrometeorological stations should pay attention to the following six points: the selection of installation location of Agrometeorological stations, the selection of power supply mode, regular calibration of Agrometeorological stations, technical after-sales support, regular maintenance of Agrometeorological stations, and data security of meteorological stations.1、 Selection of installation location of Agrometeorological station:If the agrometeorological station wants to play an appropriate meteorological monitoring effect, the equipment installation position needs special attention.1. Agricultural weather stations are generally unattended, so the location of agricultural weather stations should be selected in places with convenient transportation to facilitate management and supervision. Moreover, for the sake of safety, the location should also ensure the relative safety of the surrounding environment, otherwise it is easy to cause accidental damage to the weather station. The selection of Agrometeorological stations should also consider the reasonable layout and whether the construction site has the local agroclimatic characteristics. The climate characteristics are obvious. Using Agrometeorological stations for monitoring will be more representative.2. The installation of the agrometeorological station needs to ensure that the surrounding area is open and can not be blocked by buildings or trees. In addition, because the agrometeorological station itself depends on sensor equipment, the sensor itself is more sensitive. In order to ensure the accuracy of monitoring results, it should be far away from areas with high radiation and strong magnetic field, such as voltage transformers, high-voltage electricity, etc.2、 Selection of power supply mode: there are two kinds of agricultural meteorological stations: solar power supply and municipal power supply. Solar power supply is composed of electric positive energy storage battery and solar panel, which is suitable for application in places where it is inconvenient to supply power in the field; However, the municipal power supply will be cut off. Therefore, in order to ensure the continuity of meteorological observation, we'd better choose the agrometeorological station with both municipal power supply and solar power supply.3、 Regular calibration of agricultural meteorological station equipment: the staff in the automatic meteorological station shall check and calibrate the observation instruments in time to ensure the normal operation of the automatic meteorological station and the accuracy of monitoring data. In addition, we should also pay attention to the supervision and repair of monitoring instruments and properly back up some important monitoring instruments, so as to avoid data loss caused by the shutdown of meteorological stations due to instrument failure.In order to ensure the normal operation of the meteorological station and the accuracy of the equipment, it is necessary to regularly send the meteorological station data to relevant departments for calibration and verification, so as to avoid the loss of agricultural production due to the accuracy of the equipment.4、 Technical after-sales support: the automatic weather station is unattended. Once there is a problem with the automatic weather station, skilled maintenance personnel are required to repair the automatic weather station. In case of failure in daily use and data cannot be transmitted, maintenance personnel can be sent to repair in time. The maintenance personnel shall be relatively skilled in maintenance technology and have some knowledge of Agrometeorological stations. In case of simple problems in the automatic weather station, the equipment can be repaired to ensure the integrity and accuracy of data monitoring of the automatic weather station; Be able to communicate effectively with the manufacturer's technical support in case of complex problems.5、 Daily protective measures for Agrometeorological station:After the completion of the agrometeorological station, the daily protective measures for the equipment of the agrometeorological station is also a factor to be considered. The safety protective measures for the monitoring instruments of the agrometeorological station mainly include: first, maintaining the cleanness of the surface of the collector; Second, the weather station and its surroundings must be kept clean and tidy; Third, regularly check whether the rain bucket is firm or not; Fourth, soft objects such as soft bristles should be used to clean the temperature and humidity sensor; Fifth, ensure the smoothness of the air pressure sensor; Sixth, the computer terminal of the special agricultural meteorological station should often kill viruses and back up the data of the meteorological station.6、 Weather station data securityThe data security of meteorological stations is also the main reason affecting meteorological work. Only by ensuring the efficient collection and timely transmission of meteorological data can we ensure the authenticity and effectiveness of meteorological data, so as to form accurate meteorological prediction and management. Agrometeorological stations are generally unattended and the working environment is complex, which is vulnerable to external influence and poses a threat to data security. At the same time, with the advent of the network era, data needs to be transmitted through network channels, facing the impact of network security threats. It is easy to be damaged and tampered in the process of data transmission and processing, while the computer terminal of the weather station is vulnerable to the threat of virus and network malicious access. Improper processing will have a serious impact on data security.fqj
Eye for Detail Shines Through
Contrast was the name of the game when Bex and Wade Kimpton set about exhaustively planning the renovation of their villa.As Wade says: "We wanted something that was yin and yang; that was old and new using black and white and some greys." Along with a monochrome colour scheme, the couple has used a combination of sleek and rustic surfaces, recycled materials and industrial touches.The extension at the rear is a black, boxy pavilion with cantilevered roof in stark contrast to the street frontage where the home presents as a traditional white-painted villa (with black front door).An eye for design and detail shines through in the elegant home, not surprising given that Wade is a boatbuilder by trade and Bex has a fashion and homewares business.Their home is packed with personality and mementoes of their travels with furniture, ornaments and fittings from places such as Bali and Turkey.Wade, who was a superyacht skipper for 14 years, says they bought the home about six years ago because it had a swimming pool. They moved in a couple of years later and began planning the renovation.Architect Phillip Matz designed the extension to the rear of home to create space and light as well as provide a better connection to the in-ground swimming pool and back yard.Bex says: "The house used to have a lean-to at the back and be so dark and enclosed even though that's where you get all the afternoon sun. I wanted light, and we even made the swimming pool smaller so that we could have a sun deck and patio beside it." Wade says: "What we wanted was that you open the door and see a garden oasis out the back and the house looks like it is sitting on the edge of the water." Behind its white picket fence the home has a standard villa layout with rooms either side of a central hallway.On one side of the hallway is the master bedroom with walk-in wardrobe and en suite and beyond that the main bathroom. On the opposite side of the hallway are a bedroom each for pre-schoolers Jagger and Wilder and a fourth bedroom that could also be a study or second living area.Quirky touches are a highlight of the master bedroom's walk-in wardrobe, which has chunky, rustic wooden shelving supported by industrial style black pipe framing. These materials feature in the living areas of the house to tie the look together.Shiny copper piping recycled from the house supports the basin in the en suite and the bathroom fittings and tapware are keyed off the copper look.White-painted floorboards and mainly white walls help to fill the home with light and give it a sense of space and serenity. White dominates in the decor but the look is broken up with different patterns and textures.In the main bathroom a large standalone bath framed by geometric marble-look tiles is big enough for the whole family and, says Bex, has been known to host up to eight kids.A black pipe handrail guides you down steps to the new part of the house, which has a high stud and black aluminium joinery contrasting with the white walls. Bifolds open out to the pool area and a covered patio with louvred roof.White-painted floorboards feature in the open plan kitchen/dining/living area and have a rustic look in keeping with those in the original part of the home."When the floor layer did this part of the house, I told him to do the worst possible job he could do," says Wade. "It wouldn't have looked right with the rest of the house if all the boards in here were perfect so he put chocks in and laid them at funny angles." Scrim boards removed during the building work were used to give the concrete fireplace texture.A butler's pantry is off the kitchen, which has slick, white cabinetry softened by more rustic timber shelving and black pipe framing.Having put so much into their home's revamp, the Kimptons are reluctant to leave but need a dedicated office space for Bex's growing online fashion and homewares business.More space for the children and their energetic Vizsla dog would also be desirable."We have an open-door policy with the neighbours and all the kids around here play together," says Bex. "So we don't want to move too far away."
Discuss the Differences, Applications and Suppliers Between SASE and Sd-wan in Detail
SASE (secure access service edge) and sd-wan are two network technologies designed to connect geographically different endpoints to data sources and application resources.Sd-wan - software defined wide area network, which uses virtualization network overlay to connect and remotely manage branches. Sd-wan focuses on connecting these branches back to the central private network. Although sd-wan can be connected to the cloud, it is not built around the cloud.SASE focuses on the cloud and has a distributed architecture. SASE does not focus on connecting branches to the central network, but on connecting individual endpoints (branches, individual users or individual devices) to the service edge. The service edge consists of a distributed pop network running the SASE software stack. In addition, SASE focuses on inherent security.The difference between the two is similar to the difference between using intranet and using nut cloud to share files. Both methods can achieve the same ultimate goal, but the methods are different.Sd-wan is an increasingly mature market. Although the epidemic has hindered its development, it has maintained stable growth on the whole. SASE is relatively new because it is a new term created by Gartner in 2019. Although the SASE market is still in its infancy, many suppliers have begun to enter the market through their own SASE or similar services.1、 DifferenceThe differences between SASE and sd-wan can be divided into three categories:Relationship with cloudSecurityHow to check the flow1. SASE, sd-wan and cloud(1)SASESASE uses a private data center, public cloud, or hosting facility as a pop. These pops form the service edge of the architecture in which the SASE stack runs. In addition, these POPs are usually located in the public cloud or close to the public cloud gateway to achieve low latency secure access to cloud resources. No matter which node has enough resources to meet the user's request. SASE software can determine the best path to use when traffic reaches its endpoint. Unlike sd-wan's data center centric architecture, SASE adopts a distributed architecture. Gartner believes that when cloud services are increasingly used, focusing on a single private data center as the focus of the network will lead to inefficiency.(2)SD-WANFor sd-wan, cloud integration is only a function, not a key component. In the sd-wan supporting cloud, users connect to the virtual cloud gateway through the Internet, making the network easier to access and supporting cloud native applications. This is very similar to the SASE method.2. SafetySecurity is a key factor in the competition between SASE and sd-wan.IDG recently released an interest survey on SASE and sd-wan. The data show that 91% of respondents are interested in SASE solutions, and the key point they consider is the security that SASE can provide. Similarly, 70% of companies considering adopting sd-wan also emphasize the importance of security.(1)SASESASE focuses on providing secure access to distributed resources for networks and their users. These resources can be distributed in private data centers, hosting facilities and clouds. The security proxy can contain a secure Web Gateway, and the provider's cloud can contain a firewall as a service. In branches or other places where people gather, SASE equipment is usually used to protect the security of agentless equipment such as printers.(2)SD-WANThe design of sd-wan technology does not focus on security. Sd-wan security is usually provided through auxiliary functions or third-party suppliers. Although some sd-wan solutions have indeed achieved success in security, they are only a few. The central goal of sd-wan is to connect offices in different geographical locations to each other and to a central headquarters, which has flexibility and adaptability to different network conditions. In sd-wan, security tools are usually located in CPE's office rather than the equipment itself. Network decisions in sd-wan are made in virtualized network devices distributed throughout the network.3. SASE and sd-wan flow inspection(1)SASEIn SASE network, traffic is open at one time and can be checked by multiple policy engines at one time. The engines run in parallel without passing traffic between engines. This can save time, because the traffic will not pass from one security function to the next as in sd-wan, and will not be accessed repeatedly. In addition, these policy engines serve as many or more functions as security tools in sd-wan.(2)SD-WANSd-wan uses the service chain for traffic checking. Service chain refers to checking traffic one security function at a time, one by one. These separate functions deal with one type of threat, called point solutions. Each point solution turns on traffic, checks it, closes it, and then forwards it to the next point solution until the traffic passes through all point solutions.2、 SimilarityAlthough the ultimate goals of SASE and sd-wan are similar, they do not have many similarities in architecture. At the high level, they have one thing in common: they are both Wan and virtualization infrastructure.Both sd-wan and SASE are designed to cover a large geographical area. The difference is infrastructure. SASE's infrastructure includes private data centers, hosting facilities, or clouds acting as endpoints. These are the places where network, optimization and security functions run. In sd-wan, these functions run in the chassis of branches and headquarters. SASE and sd-wan can be controlled from anywhere. In the case of sd-wan, the DIY method usually places the control right at the headquarters of the organization, and the hosting solution will be remotely controlled by the service provider. The common management solution is similar to the hosting solution, but the organization has certain control right through the portal.Although the two infrastructures are different, they are still virtualized. Sd-wan and SASE do not rely on fixed function proprietary devices like non virtualized Wan. As mentioned earlier, SASE runs security and networking functions in the cloud or other data centers and security agents. For sd-wan, network nodes and CPE are software defined. In other words, these functions run as software.3、 Supplier1. SASE is still in its infancyNow many sd-wan vendors are also offering SASE solutions. For example, Cisco, VMware velocloud and opensystems are practicing this solution.Other organizations have devoted more of their resources to developing and deploying SASE services on sd-wan, such as PaloAlto and Cato networks.Gartner has compiled a list of suppliers that have provided SASE or have the idea to provide SASE:Gartner said, "at present, the major IAAs providers (AWS, azure and GCP) are not competitive in the SASE market." "we expect that at least one company will enter the SASE market in the next five years because they are expanding their edge network business and security capabilities."2. There are many participants in sd-wan ecologyGartner expects that the proportion of enterprises deploying sd-wan will increase from 30% in 2019 to 90% in 2023.According to IDC data, the global sd-wan market space in 2019 is USD 2.3 billion, and the compound growth rate is expected to be as high as 35% from 2019 to 2021.There are many sd-wan players in China, including start-ups, network equipment manufacturers, network operators, IDC manufacturers, public cloud operators, security manufacturers, etc.3、 SummarySASE and sd-wan are two different network technologies, which use different methods to achieve similar purposes. Both technologies aim to connect geographically distributed organizations in a flexible and adaptable way. SASE network focuses on providing cloud native security tools and takes cloud as the center of the network; Sd-wan technology is dedicated to connecting offices to central headquarters and data centers, but it can also connect users directly to the cloud.At present, although only a few sd-wan suppliers and security providers are launching SASE solutions, Gartner predicts that at least 40% of enterprises will adopt SASE strategy by 2024, that is, more sd-wan suppliers will transform to SASE in the future. Editor ajx
Best Cement Tiles Making Machine Suppliers and Price Details
Golden Engineers is the finest name as the Cement Tiles Making Machine Manufacturers in India. Our all machines is highly durable and low in cost. We work for quality and standard. Our Cement Tiles Making Machine is manufactured by using best quality of raw material. Since the decades no one beats us in the terms of quality and Price. If you are searching for the 100% durable and low cost Cement Tiles Making Machine then Golden Engineers is the best choice for you.We are also the huge manufacturers of interlocking tile making machine, fly ash brick making machine, cement tile making machine, vibrating table machine etc. Golden Engineers is the best Cement Tiles Making Machine Suppliers in India. We are the Indias largest and first company how manufacturers the customized machines. As our main focus is on the client needs and requirements. We uses the high quality of raw materials. through which our machines is highly durable and Low in cost RELATED QUESTION What is a cement tile? Cement tile is a handmade flooring building material, which they are mainly cement content (white cement for color layer, grey cement for body ). It is non-baking. The tile can be durable hundred years, that we can find those cement tile in architecture since 19 centuries, especially in the church, colonial architecture, They can be called in another name like hydraulic tile (as the name of production method) or pattern tile (as the name of large variety of pattern designs) All the patterns are able to be customized in both designs and color way, with small quantity. The color of cement tile look very vividly. Although cement tile was found over hundred years ago, cement tile is still made with traditional technique. It is secured for the last long beauty of a handmade product.
Important Solutions to Granite Suppliers Melbourne in Easy to Follow Step by Step Detail
Up in Arms About granite suppliers melbourne?Since it isnt completely natural, reconstituted stone is offered in a broad range of finishes and colours, which is fantastic if youve got an extremely specific scheme in mind. As one of the strongest substances on earth, stone is extremely durable and will persist for a lifetime, additionally it is resistant to stains and scratches and is incredibly simple to wash. Natural stone will improve your project whilst providing high performance, durability and very low maintenance. On account of the way its formed, granite is among the hardest and most durable surfaces out there. Granite is among the very best building materials you will find for the home. Please be aware that marble and granite change from supplier to supplier so if you like what you see at the same supplier, make sure that you put it on hold as you might not find the exact same again. When youre deciding what things to use crushed or decomposed granite for in your lawn, keep in mind that it comes in a wide selection of colors and granular sizes, so you may always find one which will match perfectly to agree with your requirements.Granite is a great option for outdoor paving and cladding. Beyond that, it is also very easy to maintain. It is an eco-friendly material that is built to last. Crushed granite is an amazingly versatile material that may be utilized in landscaping projects for both modest residential jobs and much larger commercial spaces.Granite offers many benefits and may be used for a large number of applications. It is not a material that is weak or easy to damage. There are some things you want to learn about granite before you approach granite suppliers. Its essential to note that crushed granite tends to get sharp edges and shapes. Choosing Good Granite Suppliers MelbourneWhether its a driveway, pathway, pool area or entertaining location, pavers are an efficient approach to use the space in your surroundings. It is possible to use stone pavers for many years with very little maintenance. Its possible for you to consider granite pavers when youre renovating your kitchen for benchtops. Granite pavers are incredibly dense and hardwearing. If youre searching for the very best granite pavers we need to offer, you can depend on RMS Traders!Choosing Granite Suppliers Melbourne Is SimpleNormally, professional rock installation business will charge by the square foot for each undertaking, but others might quote a price for the whole project or simply ask to get covered by the hour. If you are searching for reliable stone suppliers, look no more. Locating a dependable supply of excellent construction materials for your building projects might be challenging practice. Pave World is called the supplier that has the best of the very best, the maximum quality products out there. A supplier with a very selective array of granite stones isnt one who can provide you with a lot of choices and so, isnt the perfect supplier for your purpose either. Turkeys biggest supplier of travertine is currently producing stone inspired porcelain. Many retailers have cleaning products offered and only a quick wipe down will safeguard your base for a very long time.The Most Popular Granite Suppliers MelbourneLight surface scratch repair on granite demands re-polishing by an expert. Stone cladding installation demands artistic expertise and access to right products. A neighborhood driveway installer is the ideal source for cost info.Granite benchtops will boost the general appearance of your kitchen. Should you need white or black granite benchtops, Melbourne locals can benefit from our top-quality assortment of stones! Choosing benchtops for your house or business workspace is among the most exciting regions of the design practice.When it has to do with countertop materials, granite is genuinely an extraordinary option all around. Found throughout the Earth, every bit of pure stone is unique and gives the purchaser a more personalised touch to their residence or workspace. As a pure material, every bit of stone is unique and it not only adds personality to your residence, but could also boost the general value of your premises. Additionally, it uses waste materials as an alternative to quarrying new materials. Using our on-line price check tool and calculator, you may rest assured you will get the very best lanscaping materials for competitive rates. What Granite Suppliers Melbourne Is and What it Is NotIf you are interested in an intriguing appearance for your garden, think about installing a decomposed granite patio. Adding an abstract modern sculpture or classical figure to the exact garden will make a different appearance. Not only do you have to think of the aesthetic wants but the suitable needs. Why Choose Us Granite Warehouse is the ideal place to begin your stone journey. The choice really comes to the look and feel you wish to attain in your kitchen. Find out more about the benefits and disadvantages of crushed or decomposed granite, how much to budget, and whether it is the correct alternative for your premises. With our wide assortment of paving stones, you can acquire numerous design choices RELATED QUESTION How many people participate in the campaign "break the chain" in Kerala? Break the Chain is the latest social campaign started by Kerala Government in its fight against the deadly Corona Virus outbreak. The campaign was announced by Kerala Government yesterday (15/03/2020) by Health Minister- KK Shyalaja Teacher The social campaign is to promote personal hygiene and social distancing as a means to control the spread of Covid 19 dieases. Break the Chain intends to ensure personal hygiene by using hand sanitising and hand washing at offices, public spaces and houses. The campaign aims to ensure, people are sanitized regularly and ensure the break of virus spread. Minister KK Shailaja Teachers public appeal as part of Break the Chain campaign. As per this campaign, the government has mandated and will encourage all organizations, bodies and establishments to keep provisions of hand santiziers and soap/lotion dispensers to have people associated with them to wash their hands regularly. As per orders issued, companies and organizations are required to keep sanitizers at the entrance and encourage people to use it at regular intervals. Departmental heads of every organization are required to ensure their staff regularly wash their hands and sanitizes themselves. The government has directed local bodies and various local health agencies to open kiosks, booths etc at public places , bus stands, railway stations, boat jetties, airports and in government offices to allow public to wash their hands frequently.Residential associations, hotels, lodges etc are mandated to keep sanitizers or soap water dispensers at appropriate places where residents/visitors can sanitize their hands. NGOs, community associations, political parties and public organizations are requested to assist government in setting roadside kiosks, booths and parlours etc where sanitizers could be arranged for frequent sanitizing of public. Those who cant afford hand sanitizers are requested to keep a bucket of soap water or water mixed with personal disinfectants like Dettol etc so that people can wash their hand frequently. So as health authorities have started their road-side checking of travellers by stopping vehicles and exit the vehicle, where they will be mandated to wash their hands and test their temperature. As part of social campaign, Kerala Govt as sought celebrity assistance to promote the campaign and entire Malayalam cinema fraternity came forward in the campaign Many celebrities started endorsing this campaign in their social media accounts Manju Warrier Mammotty, Joju George, Saiju Kurup Tovino Thomas, Jayasurya, Aiswarya, Jayaram, Aju Varghese, Unni Mukunand, Indrajith Sukumaran, Miya George Singer Vidhu Prathap Magician Muthukad Today, most of the news channels in Kerala kept Sanitizers near the news desk and frequently streaming live with news anchors cleaning their hands as part of social awareness Most of the FMs started this campaign Trivandrum Medical Colleges School of Pharmaeuticals started inhouse production of hand sanitizers by its students and now they are distributing for free at road sides to make people use it as a praticse People have slowly started changing their profile pics to new Photo frames from DHS on this campaign as a constant reminder to wash hands Hopefully in coming days, it shall be a major challenge in social media and reduce the intensity of spread.
Migrants in Libya Detention Center Detail Dire Conditions
BENGHAZI, Libya (AP) Migrants held at a small, dilapidated detention center in the southern Libyan city of Sabha say they are being neglected by international organizations and often go hungry due to lack of food.One of the detained is Ahmed Saleh Ibrahim, a 19-year-old Sudanese who made his way into Libya with the help of smugglers last year. He was arrested by an immigration patrol in the eastern city of Benghazi and moved from one detention center to another until he was brought to Sabha, 650 kilometers (400 miles) south of the capital, Tripoli, four months ago."There's little food, and at night there are a lot of mosquitoes, and the place is dirty," Ibrahim recently told The Associated Press.Mohamed Jibril, the center's deputy manager, admits they lack "a lot of things, including a water supply," a generator and a clinic.The center consists of three buildings and can hold up to 45 migrants, but has less now after about 20 were deported back to their countries, according to Jibril.Ibrahim works daily at the center's kitchen a spacious room where wall and floor tiles are covered with dirt. Like other migrants, he sleeps on a sponge mattress or a blanket spread on the ground in a hall with grey-painted walls covered with graffiti mostly with religious messages, both Christian and Muslim the work of migrants who passed through.The migrants are given access to phones to call their families back home only when representatives of the International Organization for Migration visit, he said.Libya became a major conduit for African migrants and refugees fleeing to Europe after the 2011 uprising that ousted and killed longtime ruler Moammar Gadhafi. The EU has spent hundreds of millions of euros to equip and train Libya's coast guard and to improve the conditions of the detention centers.The migrants have also been caught in the ongoing war between Libya's U.N.-backed government based in Tripoli and the self-styled Libyan National Army led by commander Khalifa Hifter, who launched an offensive to capture the capital in April. The U.N. said in May it feared detention centers were being used to store weapons, effectively turning migrants into human shields.On July 3, more than 50 migrants were killed in an airstrike on the Tajoura detention center. The Tripoli government blamed Hifter's forces for the deaths.
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