Peripheral soldering of flip chip joints on passive RFID tags

Flip chip is the main component of a RFID tag. It is used in billions each year in electronic packaging industries because of its small size, high performance and reliability as well as low cost. They are used in microprocessors, cell phones, watches and automobiles. RFID tags are applied to or incorporated into a product, animal, or person for identification and tracking using radio waves. Some tags can be read from several meters away or even beyond the line of sight of the reader. Passive RFID tags are the most common type in use that employ external power source to transmit signals. Joining chips by laser beam welding have wide advantages over other methods of joining, but they are seen limited to transparent substrates. However, connecting solder bumps with anisotropic conductive adhesives (ACA) produces majority of the joints. A high percentage of them fail in couple of months, particularly when exposed to vibration. In the present work, failure of RFID tags under dynamic loading or vibration was studied; as it was identified as one of the key issue to explore. Earlier investigators focused more on joining chip to the bump, but less on its assembly, i.e., attaching to the substrate. Either of the joints, between chip and bump or between antenna and bump can fail. However, the latter is more vulnerable to failure. Antenna is attached to substrate, relatively fixed when subjected to oscillation. It is the flip chip not the antenna moves during vibration. So, the joint with antenna suffers higher stresses. In addition to this, the strength of the bonding agent i.e., ACA also much smaller compared to the metallic bond at the other end of the bump. Natural frequency of RFID tags was calculated both analytically and numerically, found to be in kilohertz range, high enough to cause resonance. Experimental investigations were also carried out to determine the same. However, the test results for frequency were seen to be in hundred hertz range, common to some applications. It was recognized that the adhesive material, commonly used for joining chips, was primarily accountable for their failures. Since components to which the RFID tags are attached to experience low frequency vibration, chip joints fail as they face resonance during oscillation. Adhesives having much lower modulus than metals are used for attaching bumps to the substrate antennas, and thus mostly responsible for this reduction in natural frequency. Poor adhesive bonding strength at the interface and possible rise in temperature were attributed to failures under vibration. In order to overcome the early failure of RFID tag joints, Peripheral Soldering, an alternative chip joining method was devised. Peripheral Soldering would replace the traditional adhesive joining by bonding the peripheral surface of the bump to the substrate antenna. Instead of joining solder bump directly to the antenna, holes are to be drilled through antenna and substrate. S-bond material, a less familiar but more compatible with aluminum and copper, would be poured in liquid form through the holes on the chip pad. However, substrates compatible to high temperature are to be used; otherwise temperature control would be necessary to avoid damage to substrate. This S-bond would form metallic joints between chip and antenna. Having higher strength and better adhesion property, S-bond material provides better bonding capability. The strength of a chip joined by Peripheral Soldering was determined by analytical, numerical and experimental studies. Strength results were then compared to those of ACA. For a pad size of 60 micron on a 0.5 mm square chip, the new chip joints with Sbond provide an average strength of 0.233N analytically. Numerical results using finite element analysis in ANSYS 11.0 were about 1% less than the closed form solutions. Whereas, ACA connected joints show the maximum strength of 0.113N analytically and 0.1N numerically. Both the estimates indicate Peripheral Soldering is more than twice stronger than adhesive joints. Experimental investigation was carried out to find the strength attained with S-bond by joining similar surfaces as those of chip pad and antenna, but in larger scale due to limitation in facilities. Results obtained were moderated to incorporate the effect of size. Findings authenticate earlier predictions of superior strengths with S-bond. A comparison with ACA strength, extracted from previous investigations, further indicates that S-bond joints are more than 10 times stronger. Having higher bonding strength than in ACA joints, Peripheral Soldering would provide better reliability of the chip connections, i.e., RFID tags. The benefits attained would pay off complexities involved in tweaking

Channel Sharing based Medium Access Control Protocol for Wireless Nano Sensing Network

Recent advancement and grown up technologies has enabled the development and implementation of low-cost, energy efficient and versatile sensor networks. Sensor networks are built up with sensors that have the ability to sense physical or environmental property. Assumption can be made that Wireless Sensing Network (WSN) is able to sense environmental conditions at Nano and gaseous level. This architecture of Wireless Sensor Network is maintained by a sub-layer named Medium Access Control Layer that provides addressing and channel access control mechanism among multiple nodes of the network and makes these nodes capable to communicate with other nodes through a shared medium. The hardware that implements the MAC is referred to as a medium access controller. This paper finds the problems in selection of cluster nodes and transmitting data and also proposes an improved MAC protocol to minimize the problem

Comparative Analysis of MapReduce Framework for Efficient Frequent Itemset Mining in Social Network Data

Social networking sites are the virtual community for sharing information among the people It raises its popularity tremendously over the past few years Many social networking sites like Twitter Facebook WhatsApp Instragram LinkedIn generates tremendous amount data Mining such huge amount of data can be very useful Frequent itemset mining plays a significant role to extract knowledge from the dataset Traditional frequent itemsets method is ineffective to process this exponential growth of data almost terabytes on a single computer Map Reduce framework is a programming model that has emerged for mining such huge amount of data in parallel fashion In this paper we have discussed how different MapReduce techniques can be used for mining frequent itemsets and compared each other s to infer greater scalability and speed in order to find out the meaningful information from large dataset

Performance and supply chain analysis of Binalebu-1 in some selected areas of Bangladesh

The study was conducted to find out the performance and supply chain of Binalebu-1 in four major Binalebu-1growing areas of Bangladesh, namely Cumilla, Mymensingh, Rangpur and Dhaka districts. Simple random sampling technique was followed for this study. The average cost of lemon production was estimated at Tk. 206127 per hectare of which about 68% was variable cost and 32% was fixed cost. Human labour cost was the lion share (32%) of total cost and it followed by irrigation cost (6.63%), Insecticide (2.64%) sapling (2.60%), and in the study areas. The average yield of Binalebu-1 was recorded 28.32 t/ha in all study areas while it was highest in 3rd year (30.24 t/ha) followed by 2nd year (28.17 t/ha) and 1st year (26.58 t/ha). The average gross return, gross margin and net return of lemon were found to be Tk 744517.62/ha, Tk 454521.67/ha, and Tk 538390.75/ha, respectively. Average BCR was found to be 2.71 on the basis of total cost. Supply chain was classified into four types: Channel 1: Accounts for 40 % which was ranked as I; Channel II: Accounts for 20 % which was Ranked as II; Channel III: Accounts for 18 % which was Ranked as III, Channel IV: Accounts for 12 % which was ranked as IV; Channel V: Accounts for 10 % which was Ranked as V. It was revealed that the value addition of the Faria, Bepari, Paiker, Arathdar, Retailer were Tk.135, Tk.95, Tk.55, Tk.39 and, Tk155 per quintal, respectively

CLOUD COMPUTING TECHNOLOGY IN BANGLADESH: A FRAMEWORK OF SOCIAL &ECONOMIC DEVELOPMENT

Cloud computing is currently one the most hyped IT innovations that promises potential opportunities for business and social innovation as well as modernizing ICT. For developing countries like Bangladesh, this technology aims to provide the clients a cost effective and convenient means to manage the huge amount of IT resources and thus offer strong possibility of accelerating social and economic development, even in this time of limited resources. As the information technology industry goes through a major shift, founded on the Internet as a platform, new opportunities for Bangladesh are open to employ technology at a lower cost and with much greater ease and success than in the past. The Main purpose of our strategy is to help organizations of public and private sector in Bangladesh to adopt cloud computing technology opportunities and prevent its obstacles through our proposed framework. In this article, we tried to assess different aspects and strengths, weaknesses, opportunities and threats of these strategies for Bangladeshi organizations and enterprises. In addition some recommendations are provided for Bangladeshi organizations and enterprises to help them to adopt cloud computing technology

Determinants of Drought Tolerant Rice Variety Adoption: Evidence from Rural farm Household in Northern Part of Bangladesh

The drought-tolerant rice variety Binadhan-19 study was conducted in five districts: Mymensingh, Ranpur, Pabna, Rajshahi and Chapainwabganj of Bangladesh. A total of 200 farmers were randomly selected (40 from each location) to collect the data with a pre-designed questionnaire. Tabular, descriptive statistics and Probit model were used to fulfil objectives. The estimated log-likelihood value of gender, farm size, yield, agricultural extension services have a statistically and significant positive effect on the adoption of the variety. The household characteristic related variables such as age, experience, annual income, human labour, duration of the variety have no statistically significant effect on the adoption of the variety. Marginal coefficients indicate that if male farmers increased by 100%, the probability of adopting the Binadhan-19 variety would increase at 38 times more likely to adopt the variety. If the farm size of Binadhan-19 increased by 100%, the probability of adopting the variety would be increased by 0.07%. A farmer who has access to agricultural extension service is about 39 times more likely to adopt the variety. Again, if the yield increased by 100%, adopting the varieties would increase by 0.08%. The marginal coefficients of locations and soil fertility are negatively significant, indicating that if these two variables increased by 100%, the probability of adopting the varieties would decrease by 0.06% and 30%, respectively

The transformation of education during the corona pandemic: exploring the perspective of the private university students in Bangladesh

Purpose – In 2020, the education system was preliminary halted by the COVID-19 crisis and went through radical improvisation, and online-based distance learning was the only plausible initiative to continue educational activities ensuring health guidelines properly. However, in reality, such desperate measure in case of a lower-middle-income developing nation lacking proper structural capabilities raised some issues and concerns for both pupils and mentors, and this study aims to explore the practice of online-based distance learning in private universities of Bangladesh and the challenges associated with it. Design/methodology/approach – This exploratory research is qualitative in nature. A total number of 89 undergraduate level university students from different private universities were divided into two main clusters and interviewed in depth. Findings – The findings of this paper revealed that common developing country syndromes like improper technological infrastructure development, limitation to devices or internet accessibility and financial hindrances can disrupt the harmony of the online learning experience. Also, the lack of tech literacy has created a huge tension and psychological inertia among both the teachers and the students. Social implications – The coronavirus pandemic event, with its dreadful influence, is creating immense mental pressures for students to cope well with the online learning system. Comprehending the underlying challenges affiliated with online-based distance learning and enabling faculties or respected personnel with training and development programs to handle impediments better way, this learning initiative can ensure the best outcomes. Originality/value – The significance of this study lies in comprehending the feasibility of online-based education regarding lower-middle-income developing nation context and the realism of such learning process's acceptability considering its actual effectiveness

Revitalizing Public Health, Application of Service Design Approach to Reduce Tobacco Consumption among Youth – A Case Study in Cumilla City

The consumption of tobacco among young individuals is a significant and urgent issue in the field of global public health, since it has wide-ranging implications for both individuals and societies. The city of Cumilla, situated in Bangladesh, presents a compelling case for examining novel approaches to address this problem. This study employed a service design methodology to investigate and execute interventions that prioritized user needs, fostered engagement, and were customized to address the unique requirements of the young community in the local area. The study used a combination of qualitative and quantitative methodologies to evaluate the effects of the implemented services and campaigns on the prevalence of tobacco use among young individuals. This study aimed to decrease tobacco usage among teenagers and empower them to make informed decisions by employing a combination of co-creation workshops, multi-channel awareness campaigns, school-based programmes, and user-friendly cessation support services. The results indicated that using a service design approach has the potential to act as a successful catalyst for modifying behavior and encouraging the adoption of healthier lifestyles among the youth residing in Cumilla City. This thesis further emphasized the significance of stakeholder collaboration and the enduring sustainability of these endeavors in Cumilla city