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No. 34/2012 (Oct. 15, 2012)
Sprayed-on or printed solar cells.
Let's paint the roof with special paints and we'll have a home power plant... This vision is not so awkward after the announcement that scientists have built a solar cell based on Colloidal Quantum Dot (CQD) films with a record-breaking efficiency of 7%, about 40% higher than that of the best previous devices using CQDs.Although commercial cells based on traditional silicon technology have efficiency of 15-20%, which is up to three times higher than in the case of the new achievement, the sharp increase in CQD cell efficiency promises a number of interesting applications. They will result from the way of the production of the new cells, with the use of special paints or even just by printing using inkjet printers.
a) diagram of the solar cell made out of colloidal quantum dot film
b) cross-section photographed by a scanning electron microscope
b) cross-section photographed by a scanning electron microscope
(source: physicsworld.com)
Colloidal Quantum Dot (CQD) films employ the recent developments in nanotechnology, particularly the phenomena taking place in so-called "Quantum dots" - ultra-thin semiconductor layer with unique light-capture properties. Quantum dots is an integrated thin film of thickness several to tens of nanometers, divided into cells ( "dots") of similar dimensions. It is worth to note that the wavelength of visible light ranges from 400 to 700 nm and 1 nanometer is one millionth of a millimeter.
The capturing of photons that increase the energy of electrons is the basis of all solar cells. The small surface and thickness of a "quantum dot" restricts the free movement of particles. By analogy to a shooting gallery, the photon has a greater chance to hit the immobilized electron instead of one constantly vibrating in a haphazard manner - hence the greater efficiency.
The problem is the selection of materials and mastering the technology, but the prospective performance levels are impressive, especially when combining existing and quantum technologies. In October, the United States Air Force commissioned Magnolia Solar to develop nanotechnology solutions for reaching the efficiency of solar cells intended for the defense and space industries close to 50%!
The capturing of photons that increase the energy of electrons is the basis of all solar cells. The small surface and thickness of a "quantum dot" restricts the free movement of particles. By analogy to a shooting gallery, the photon has a greater chance to hit the immobilized electron instead of one constantly vibrating in a haphazard manner - hence the greater efficiency.
The problem is the selection of materials and mastering the technology, but the prospective performance levels are impressive, especially when combining existing and quantum technologies. In October, the United States Air Force commissioned Magnolia Solar to develop nanotechnology solutions for reaching the efficiency of solar cells intended for the defense and space industries close to 50%!
The total power used by humans is only about 0.02% of the solar radiation power reaching the Earth. The solar energy received by the Earth during six months equals the amount of energy contained in the estimated resources of the currently used fuels - coal, oil, gas and uranium.
The total energy that reaches a horizontal surface throughout the year ranges from 600 kWh/m²/year in the Nordic countries to more than 2500 kWh/m²/ year in central Africa.
All the energy of solar radiation absorbed by the Earth, also used in any form by plants and animals, is transformed into heat and then emitted as infrared radiation into outer space.
Development of a new generation of photovoltaic cells will allow for better absorption and use of solar energy.
The total energy that reaches a horizontal surface throughout the year ranges from 600 kWh/m²/year in the Nordic countries to more than 2500 kWh/m²/ year in central Africa.
All the energy of solar radiation absorbed by the Earth, also used in any form by plants and animals, is transformed into heat and then emitted as infrared radiation into outer space.
Development of a new generation of photovoltaic cells will allow for better absorption and use of solar energy.
- 1st place: "Dish and fork" by Wojciech Domagala. For an interesting composition, presenting a play of the subject and its shadow. The use of black and white photography enhances the purity of the form.
- 2nd place: "On the carousel" and "The magnet of souls", both by Elzbieta Bakowska. For the geometric approach to the world around us. "On the carousel" is a combination of mathematical geometry with nature, life, communication, and "The magnet of souls" shows some curvature which can be associated with a deformation of the reality.
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- 3rd place: "Something for the birds" by Marcel Kasprzak. For the desire to spread new technology among our smaller friends and doing so in a professional manner (directional antenna) :)
The table below shows fiber optic cables offered by DIPOL. They are divided into the mentioned earlier four groups.
1) MM - Multi-Mode fiber(s)
2) SM - Single-Mode fiber(s)
2) SM - Single-Mode fiber(s)
Ultimode IDC duplex cables L7202, L7502 are usually used in indoor networks based on point-to-point architecture. Applications which require a larger number of fibers use distribution cables with four ( L7504) and eight ( L7508) single-mode fibers, or with four ( L7204) and eight ( L7208) multimode fibers.
Easy access cables Ultimode BS L7712 and L7724 are specially designed for applications in multi-story buildings. Thanks to a special structure - reinforced loose tube made of LSZH material - the distribution of the fibers to the end users cannot be simpler.
Universal cables Ultimode UNI L7354, L7358, L7644 and L7648 can be used inside buildings as well outdoors (linking campus buildings etc). Because the universal cables have central tubes filled with hydrophobic gel, they are dedicated mainly for horizontal cabling.
Easy access cables Ultimode BS L7712 and L7724 are specially designed for applications in multi-story buildings. Thanks to a special structure - reinforced loose tube made of LSZH material - the distribution of the fibers to the end users cannot be simpler.
Universal cables Ultimode UNI L7354, L7358, L7644 and L7648 can be used inside buildings as well outdoors (linking campus buildings etc). Because the universal cables have central tubes filled with hydrophobic gel, they are dedicated mainly for horizontal cabling.
How to solve the problem of interference between overlapping or neighboring channels in antenna systems?
Combination of signals from antennas aimed at different terrestrial TV transmitters or from a terrestrial antenna and a cable television network will result in interference when some of the RF channels from the sources are identical or close. In such cases, the subnetworks have to be isolated by a switch, which will allow for the selection of the current source. The cheapest solution may be based on Signal E2022 switch that has to be operated manually.
IR-controlled CATV/DVB-T switch MST-01 E2024
MST-01 E2024 switch is controlled by any infrared remote control (TV, DVD, SAT, etc.). The alternate input selection is performed when the user holds down any key on the remote for 3 seconds. Thanks to high isolation between inputs (>50 dB), the sources can contain signals distributed on adjacent or even on the same channels (in the case of digital signals).
Two scenarios of using the MST-01 E2024 switch:
-In the first, two terrestrial TV antennas aimed at different transmitters receive signals of similar frequencies (e.g. adjacent RF channels).
- In the second, some DVB-T channels use the same RF channels that are employed in CATV network.
-In the first, two terrestrial TV antennas aimed at different transmitters receive signals of similar frequencies (e.g. adjacent RF channels).
- In the second, some DVB-T channels use the same RF channels that are employed in CATV network.
CCTV systems with limited access to DVRs.
In many cases the surveillance staff should not have physical access to the DVRs. The DVRs are often located in places with higher security levels, such as server rooms. In such situations, it is necessary to provide the surveillance staff with the video necessary for their job.The diagram below shows a monitoring system based on high-speed PTZ cameras PH-33 M1196. The Signal DL-6208 M76208 DVR has been placed in a dedicated room. The surveillance booth is located ca. 1 km away. The surveillance staff can control the PTZ cameras and oversee the video channels, but cannot change any settings of the DVR.
A video surveillance system with the DVR protected from physical access
The video signals from the DVR to the surveillance booth and the control PTZ signals in the opposite direction are transmitted by sets of active Etrix video baluns M16742 and M16743. In the case of a much greater distance and possibility of use/deployment of a fiber optic cable, the task can be performed by ULTIMODE video converters.
How to diagnose IP CCTV systems?
Long delays in imaging, no recording and loss of communication with the IP cameras, are the most common problems in IP CCTV systems. NUUO has implemented in its video surveillance software a diagnostic tool dedicated for monitoring the system and recording its activity. "Resource Report" allows for quick identification of problems.
"Resource Report" is a part of NUUO surveillance which displays diagnostic data
The report provides information on many parameters:
- System Health: CPU temperature, motherboard temperature, fan speeds - the information is vital for uninterpreted operation of the computer.
- CPU Loading: this parameter shows the percentage of CPU load. Long periods of the load close to 100% may cause delays in viewing and gaps in the archiving of the video material.
- Memory Usage: indicator of the memory used and available. Any problems with memory may cause instability of the system.
- Logical Disk Free: information on disk space utilization. HDD with bad sectors will be full in a shorter time and the data retention period will be shorter as well; more serious failure may disable any recording functions.
- Network Utilization: excessive values may overload the network and block access to some cameras.
Advanced Resource Report in NUUO software
All the parameters can be traced using statistics, which allows for early detection of faults.
How to build a Wi-Fi network in n standard?
If the Internet connection is provided by a cable TV operator or local ISP via a cable modem with Ethernet interface or directly via Ethernet cable, the user needs a router with WAN port in the form of an Ethernet port (RJ-45). Currently, the best solution is the application of a router using the 802.11n standard.An example of efficient home/SOHO network:
The home/SOHO network employs:
- 1 - TP-LINK TL-WDR4300 N3260 router shares the Internet connection within a wired network (through 4 LAN ports) and wirelessly (at speed up to 300 Mbps in 2.4 GHz band and up to 450 Mbps in 5 GHz band),
- 2, 3 - TP-LINK TF-3239DL N2999 - the PCI network interface cards connect desktop computers to the wired LAN, 4, 5 - wireless USB adapters TP-LINK TL-WN821N N3221 - allow computers to connect to the router wirelessly at speeds up to 300 Mbps.
New products offered by DIPOL:
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Worth reading:
How to power cameras via coaxial cable at distances up to 800 meters. Supplying power for 12 VDC cameras over distances greater than 50 meters has always been one of the major problems faced by CCTV installers. While the video transmission over a few hundred meters is no obstacle, DC power supply is possible at a relatively short distances, especially with typical cables having cross section up to 1 mm2... more
Typical application of the PoC-P201 M16201 set in a CCTV system
Video surveillance of remote sites - media converters. The distance between the monitoring center and the industrial plant (see the figure below) exceeds the transmission capabilities of coaxial and twisted-pair cables. The long distance and high interference levels do not allow effective application of a wireless link... more
Application of media converters and fiber-optic link for video surveillance of a remote industrial plant
Back focus in CCTV cameras. There are situations that after installation of a lens to the camera, the focus is not good. It is more probable at extreme zoom settings. The countermeasure is to adjust the distance from the sensor to the rear of the lens. This regulation (called back focus) is usually possible with the use of a special ring secured by a screw... more
The back focus in Sunell box cameras
can be set with a rotary ring secured from below with a screw
can be set with a rotary ring secured from below with a screw
