Study on Optical and Thermal Uniformity of LED Filament Based on Flip Chip1

The LED filament has become a research hotspot in industrial and academic fields. The filament was fabricated by the flip LED chip, and its optical and thermal uniformity was tested and analyzed in detail. The color temperature (CT), brightness and surface temperature (ST) of LED filament at different positions was measured by BM-7 aiming point luminance meter and Ti-32 infrared thermal imager respectively. The experimental results show that the brightness and ST of the filament conformed to the Lambert distribution. The filament was simulated by lightTools optical software and FLOEFD thermal software respectively, and the simulated illumination and temperature distribution were the same as the test results. Experimental results show that the CT and brightness of LED filament on both sides was 4.23% and 9.27% lower than that of the middle position, respectively. The ST difference of the whole device was 9.80 C. The thermal parameters of LED filament were simulated by FLOEFD software. The simulated results indicated that the ST was distributed with high level in the middle and low level at both sides, the results of simulation and experiment are consistent. Therefore, it was reveled that the LED filament prepared based on the LED flip chip has good optical and thermal uniformity and be feasible as a new type of LED light source.

Optimum Composition of Vacuum Content in a Spiral-Like Flexible Chimney-Based LED Bulb1

This paper introduced the gas flow and optimization of a spiral-like flexible chimneybased LED bulb by a combined mathematical and experimental study. A mathematical model of spiral flexible LED bulb considering nature convection, radiation and heat transfer was established by the FLOEFD software based on the finite element method (FEM), and was also compared with the experimental result. The effect of chimney-self based and vacuum content on the thermal performance of a bulb was studied. A thermal resistance model was proposed for analytical model. Compared with the filament with a stretch height of 3cm, the chimney effect can reduce the average junction temperature of filament by 6.38 ℃ (through the experiment) and 6.48 ℃ (through the simulation) respectively. The results revealed that the chimney effect has a huge impact on the gas flow in the bulb. The cause of the phenomenon is that flexible LED filament can improve the gas flow by changing self-shape instead of other cooling device. A vacuum content was introduced in the bulb and composition was optimized by using analytical model. The filament temperature in optimized bulb could decrease 6 0C than full filled with helium.

Metal Oxide Thin Films for Chemical and UV Sensors

Highly sensitive and fast responding Titanium Dioxide (TiO2) nano sensors are developed for CO gas and other materials such as methanol and methane. Nano-porous TiO2 thin films are prepared from a colloidal solution of TiO2 nano particles (P-25) in ethanol by spray pyrolysis deposition (SPD) technique. Initially the TiO2 films are grown at 60 0C and after the deposition, backed in an oven at 65 0C overnight and then annealed at 450 0C for one hour to get anatase phase. The surface morphology and structural properties of the films are studied using SEM and XRD. For sensor applications, two gold contacts separated by 0.25 mm are made on quartz substrate. A sensing and testing system has been developed based on change in the resistance of the TiO2 film. CO gas (2% in Air) through mass flow controller is used for repeated five minutes cycles of air and CO at different temperatures in the range of 200 0C to 350 0C. Response and sensitivity of the sensor has been studied. Same apparatus and sensor is also used to detect UV, methane and methanol respectively.

Smart Cameras in Embedded Systems

A smart camera performs real-time analysis to recognize scenic elements. Smart cameras are useful in a variety of scenarios: surveillance, medicine, etc. We have built a real-time system for recognizing gestures. Our smart camera uses novel algorithms to recognize gestures based on low-level analysis of body parts as well as hidden Markov models for the moves that comprise the gestures. These algorithms run on a Tri media processor. Our system cans recognize gestures at the rate of 20 frames /second. The camera can also fuse the results of multiple cameras. The smart camera – a whole vision system contained in one neat housing can be used anywhere, in any industry where image processing can be applied. Companies no longer need a cabinet in which to keep all their computing equipment: the computer is housed within the smart camera. In the pharmaceutical industry and in clean rooms – when not even dust is allowed – this can be a big advantage. A single square meter of space can be comparatively very expensive if there is no need for a component rack or cabinet, simply a smart camera, and then this could save a lot of money.

Broadband Proximity Coupled Microstrip Planar Antenna Array For 5g Cellular Applications

A novel low-cost, high-gain millimeter-wave antenna has been presented. The antenna is a 6 × 5 proximitycoupled planar array suitable for 5G cellular applications. Good agreement between simulated and measured results achievedshows thattheproposedantenna structure is efficientinachievingbroadbandcharacteristicsand lowsidelobe levels with a compact size. The antenna has a gain of 21 dBi over a bandwidth of 27.5-28.5 GHz. It also exhibits an impedance bandwidthof 9.8%from26.04to28.78GHz.

Polymer Electronic System

Main Polymers molecules formed of many identical units, bond to each other into long chains. For a polymer to be electrically conductive it must imitate a metal – the electrons in the bonds must be freely mobile and not bound fast to the atoms. In 2000 Alan Heeger, Alan MacDiarmid and Hideki Shirakawa were awarded the Nobel Prize in Chemistry for showing how polymer can be made to conduct electric current. One condition for this is that the polymer should consist of alternate single and double bonds, termed conjugated double bonds. At present, the electronic world is very much dominated by inorganic materials, in particular silicon. The Nobel Prize hasn’t been a milestone in the progress of polymer electronics, but it showed the importance of this branch of knowledge. New word, “polymer” has appeared in electronic vocabulary as a short name of this knowledge and quickly developed technology

Electrochemical Determination of Trace Pb (II) by The Modified Glassy Carbon Electrode Compositing MultiWalled Carbon Nanotubes-Nafion-Bi Film

A modified glassy carbon electrode (GCE) compositing multi-walled carbon nanotubes (MWCNTs), Nafion and bismuth film was prepared and applied for the sensitive detection of trace Pb (II). MWCNTs were dispersed into ethanol by ultrasonication in the presence of Nafion and the nanotubes are coated onto the bare GCE. After that, an extra Nafion adhesion agent is added to the electrode. By the in situ plating, a bismuth film was fabricated on the MWCNTs-NA/GCE, making the desired electrode, MWCNTs-NA-Bi/GCE. The modified electrode was characterized by differential pulse anodic stripping voltammetry, scanning electron microscopy, and cyclic voltammetry. A deposition potential of –1.4 V (vs. Ag/AgCl) and a deposition time of 300 s were applied to the working electrode under stirred conditions after optimizing. Nanotubes and Nafion concentrations and pH were carefully optimized to determine trace lead ions by using the electrode as an electrochemical-sensing platform. Nafion effectively increased the stability and adhesivity of the composite film. The MWCNTs-NA-Bi film modified electrode can remarkably increase the anodic peak current of Pb2+. The sensitivity of MWCNTs-NA-Bi/GCE is 4.35 times higher than that of the bare GCE with bismuth film. The prepared electrode showed excellent stability and reproducibility and can be applied for determination of Pb2+ contained wastewater.

Fault Tolerant Reliable Protocol (FTRP) Performance Evaluation in Wireless Sensor Networks: An Extensitive Study

Fault Tolerant Reliable Protocol (FTRP) is proposed as a novel routing protocol designed for Wireless Sensor Networks (WSNs). FTRP offers fault tolerance reliability for packet exchange and support for dynamic network changes. The key concept used is the use of node logical clustering. The protocol delegates the routing ownership to the cluster heads where fault tolerance functionality is implemented. FTRP utilizes cluster head nodes along with cluster head groups to store packets in transient. In addition, FTRP utilizes broadcast, which reduces the message overhead as compared to classical flooding mechanisms. FTRP manipulates Time to Live values for the various routing messages to control message broadcast. FTRP utilizes jitter in messages transmission to reduce the effect of synchronized node states, which in turn reduces collisions. FTRP performance has been extensively through simulations against Ad-hoc On-demand Distance Vector (AODV) and Optimized Link State (OLSR) routing protocols. Packet Delivery Ratio (PDR), Aggregate Throughput and End-to-End delay (E-2-E) had been used as performance metrics. In terms of PDR and aggregate throughput, it is found that FTRP is an excellent performer in all mobility scenarios whether the network is sparse or dense. In stationary scenarios, FTRP performed well in sparse network; however, in dense network FTRP’s performance had degraded yet in an acceptable range. This degradation is attributed to synchronized nodes states. Reliably delivering a message comes to a cost, as in terms of E-2-E. results show that FTRP is considered a good performer in all mobility scenarios where the network is sparse. In sparse stationary scenario, FTRP is considered good performer, however in dense stationary scenarios FTRP’s E-2-E is not acceptable. There are times when receiving a network message is more important than other costs such as energy or delay. That makes FTRP suitable for wide range of WSNs applications, such as military applications by monitoring soldiers’ biological data and supplies while in battlefield and battle damage assessment. FTRP can also be used in health applications in addition to wide range of geo-fencing, environmental monitoring, resource monitoring, production lines monitoring, agriculture and animals tracking. FTRP should be avoided in dense stationary deployments such as, but not limited to, scenarios where high application response is critical and life endangering such as biohazards detection or within intensive care units.

Verification of Antenna Sensor with Commercial Handsets By Applying Radiative Calibration Method

This paper describes an antenna proximity sensor for mobile and applications based on the measured reflection coefficient using a bidirectional coupler. A bidirectional coupler which uses forward and reverse parameters is located between radiated antenna and RFFE (RF Front-End). The measured reflection coefficient proved high chances to act as an antenna sensor. The proposed antenna proximity sensor showed excellent performance and some of the test results with Samsung smartphone are attached to prove it.

Internet of Things (IoT) is Smart Homes and the Risks

Undoubtedly is a technological revolution that has certainly focused on the interest of software development companies, companies of IT, hardware design, networks and artificial intelligence. A technological revolution that started a few years ago and has evolved rapidly, thanks to the technological evolution of IT and networks. It is a combination of many communication protocols, sensors and other intelligent technologies, the correlation between smart technologies, networks and services that all together complete processes in order to achieve the result for which they were installed. In advanced technology countries, both simple users and industry use IoT where sensors are simplified and automated at home and in industry, there is continuous monitoring, control and prediction of product failure for the benefit of efficient production of high quality products and control production at each stage of product processing / production. Someone could well think and say that all this is fantastic and that we have solved the problem of organization, easy life without further thoughts and worries since everything is done automatically.An IoT in an intelligent house could literally regulate everything, using sensors and appropriate software could talk with a human person, as well as someone could appropriately entice all that security and literally take full control of the premises of a home with consequences from minimal to catastrophic including the complete destruction of a home.