Research

INCDCSZ, National Conference “New approaches in research on potato, sugar beet, cereals and medicinal plants given the challenges posed by global climate and economic changes”, 27-28 November 2018, Brasov, ROMANIA

Putting Internet-of-Things at the Service of Sustainable Agriculture. Case Study: SysAgria; authors: Adrian ZARNESCU, Razvan UNGURELU, Mihai SECERE, Gaudentiu VARZARU.

Since the beginning, Precision Agriculture, and now Agriculture 4.0, were based on advancement in electronics, agriculture research and emerging technologies. Syswin Solutions has been focused on Internet-of-Things, since it seems to be more adequate compared to drones or satellite imagery because it offers much more complete data from sensors placed directly in the cultivated environment, and designed SysAgria: a system that provides comprehensive, real-time environmental information and development conditions at various phenological stages of crops, fruit trees, vines and vegetables, on the basis of which proactive treatment, planned fertilization, sowing and harvesting can be achieved. The system monitors the vital parameters of soil, air and light and identifies prototypes through a series of intelligent algorithms that analyze the data obtained and correlates them with a relevant history of the culture. Built using very low power consumption circuits, the system is energetically independent since it uses solar power and optimized algorithms for communication. Data is available anywhere in the cloud, thus the farmer can act immediately if parameters change. Syswin Solutions has five systems under test in real operating conditions, in different places around Romania, in greenhouse and in field, for monitoring cereals and vegetables. The paper presents the SysAgria system and some eloquent results of the monitoring. Soil sensors placed at different depths revealed possible water absorbtion problems. The automation of the ventilation in the greenhouse has been shown to be beneficial for plant development.

2018 IEEE 24th International Symposium for Design and Technology in Electronic Packaging (SIITME), 25-28 octombrie 2018, Iasi, Romania

Study of the Waterproof Shelter Colour Influence on the Atmospheric Temperature and Humidity Measurements for an Internet of Things Application; authors: A. Zarnescu, R. Ungurelu, M.I. Macovei, C. Coman, G. Varzaru

Atmospheric temperature and humidity are parameters of great interest in precision agriculture or air quality assessment in urban agglomerations The emergent technology of Internet of Things comes with the possibility of obtaining information from the field using low power consumption devices equipped with sensors and communication circuits. A device for measuring atmospheric temperature and humidity was built and housed in an acrylonitrile butadiene styrene material Due to the solar irradiance, the body of the enclosure gets warm and could alter the measurements by thermal conductivity and radiant energy The study investigates the influence on the measurements of these parameters by the colour of the waterproof shelter since there are tendencies to cover it with different paints for artistic design reasons Three different colours were taken into consideration, white, grey and black Experiments have to be performed simultaneously in order to meet the same input conditions for solar radiation and relative humidity.

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Considerations regarding Computer Aided Design of a structure to be manufactured in Occam technology, authors: Victoria Soare, Gaudentiu Varzaru, Adrian Zarnescu, Razvan Ungurelu, Ciprian Ionescu.

Occam technology comes with significant changes in the way the electronic modules are made because two processes, the fabrication of the printed circuit board and the

assembly of the electronic module, are replaced by a single one A compact structure containing the components and the interconnection layers are created one by one on a single line production While there are documented several approaches of the domain from the technologist’s point of view, there is not known any document about the

designer’s point of view, except for some hints from the promoter of the new technology This work is focused on the problems that the new approach of realizing the electronic module brings to the designer Since we usually are using Altium Designer as computer aided design software, we investigated what changes occur when designing for Occam technology The primary change is in the PCB Library where all the land patterns should be smaller.

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Investigations Related to Electrically Conductive Adhesives Pastes Usage on SMT Lines, authors: Mihai Branzei, Marian Vladescu, Bogdan Mihailescu, Ioan Plotog, Gaudentiu Varzaru.

The paper presents the investigations of bonds mechanical strain function of duration of curing at different fixed curing times to evaluate the possibilities of bonding process on SMT line by using electrically conductive adhesives pastes (ECAP). The experiments will be performed by keeping test PCBs up to 30 minutes (5/10/15/20/25/30 min) at 130⁰C. The test PCBs contain 0Ω 1206 chip resistors having conductive paste traces realized by printing on FR4 support. The paper presents the results and their interpretation of the microfractography analysis of the chip resistors bonds and the energy dispersive X-ray microanalysis (EDXMA) after resistors bonds shear tests as function of curing period. The experiments become a first step for defining ECAP for usage on SMT line in order to extend ECAP applications in electronics.

Assessment on using Solderless Assembly for Electronics in Space Applications, authors: Ciprian Ionescu, Gaudenţiu Vărzaru, Mihai Branzei, Norocel-Dragoş Codreanu, Ioan Plotog, Paul Svasta.

The paper presents the results of our investigation in implementing a solderless assembly process for electronics. The addressed technology is known as the Occam process and was patented by Verdant Industries. It is presented our proof of feasibility, at least for a prototyping phase on a single connection layer. Different from the original process that employs for the interconnection tracks a chemical (electroless) copper metallization, we used a new conductive paste, especially developed for printed tracks. Beside the qualitative description of technological steps required to produce the Occam module, there are presented also some quantitative results on the resistance of tracks printed with this conductive paste.

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Mechanical Properties of LEDs Bonds Realized with Conductive Adhesives Paste, authors: Mihai Branzei, Marian Vladescu, Ioan Plotog, Gaudentiu Varzaru, Bogdan Mihailescu.

The SW150 and the new types SW180 of Electrically Conductive Adhesives (ECA) dedicated to printing circuits1, meeting RoHS EU Directive2, were used, according to REACH EU Regulation3, to bond optoelectronics components, LED type, on test printed circuit boards (TPCBs) having daisy chain interconnection structures. Mechanical properties of LEDs bonds function of temperatures by measuring shear forces applied on each of bonded LEDs maintaining TPCBs at different temperature from ambient to 398 K (125 °C), were investigated. The shear forces measured values, the LEDs bonds micro sections and the microfractography after shear testes analyses and interpretations, facilitate the construction of a database that provides support for the development of temperature-sensitive optoelectronic device assembling solutions by bonding, using ECA. These solutions ensure avoidance of their functional temperature failures during classical assembly processes, comparing ECA curing and reflow temperatures.

Integrating Soil pH Measurement Into An Internet Of Things Application, authors: Adrian ZĂRNESCU, Răzvan UNGURELU, Marius – Ionuţ MACOVEI, Gaudenţiu VĂRZARU.

Soil pH is an indicator of the soil quality because it affects plant growing The work presents a device for soil pH determination on site and remote transmission of the result. Normally soil samples are taken from the field and tested in door in aqueous solutions using However, it was an increasing demand for on site measurements materialized in a plethora of stand alone devices Most of them offer a narrow range of pH values, e g 3 to 8 because the majority of plants has an optimum range between 5.5 and 7.5. The Internet of Things exigencies have led to design a node of multiple sensors including soil pH measurement with an increased precision Therefore, it was used a sensor for
hydrogen ion activity measurement based on glass membrane as a junction between the soil solution and a reference solution The probe was calibrated using pH known solutions and then tested on different soil samples all data being remotely collected.

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The 41st International Spring Seminar on Electronics Technology, ISSE, May 16–20, 2018, Zlatibor, Serbia

Properties Investigations on Copper Based Printed Conductive Pastes Electrical Joints, authors: Mihai Brânzei, Ciprian Ionescu, Ioan Plotog, Gaudenţiu Vărzaru.

The paper presents the mechanical and electrical properties of the joints as function of curing temperatures. These are made by printing a SW180 type ECAP (Electrically Conductive Adhesives Pastes) on printed circuit boards (PCBs) having daisy chain interconnection structures: one type of structure realized by printing ECAP on FR4 support, the chip components being placed into ECAP volumes corresponding to pads zones, the other type was etched using classical PCB technology in two HASL finishing types, leaded and lead-free. The micro-sections analysis of electrical joints and the microfractography analysis after shear testes performed on zero ohms, 1206 casing chip components are presented and interpreted. The database created as experiments results assures much better understanding of ECAP bonding processes as function of their curing temperature and offers the possibility to increase the reliability of ECAP applications in electronics.

Crossroad Traffic Monitoring Using Magnetic Sensors, authors: Adrian Zarnescu, Razvan Ungurelu, Andra Gabriela Iordache, Mihai Secere, Madalina Spoiala.

One of the directions addressed by the SmartCity concept is traffic management The detection of vehicles on the road has been addressed through several methods developed based on different types of sensors or devices Herein is presented an attempt to use a relatively new method of detection based on the measurement of the disturbance of Earth’s magnetic field by metallic vehicles The work describes the applied research for the design and test of a cost effective vehicle detection module based on a magnetic sensor with very low power consumption and data transmission over wireless radio frequency link The tests have been focused on finding the proper algorithm in order to obtain the best accuracy of vehicle detection and lowest power consumption Experiments of the module were performed in the laboratory and at a crossroad in the city.

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A cost-effective solution for remote Carbon Dioxide indoor monitoring, authors: Gaudentiu Varzaru, Adrian Zarnescu, Razvan Ungurelu, Andra Gabriela Iordache

As the forth atmospheric gas in order of concentration, CO 2 is proven to affect health and productivity, thus monitoring its presence in offices, schools and industrial buildings has become a good practice The present work was generated by a real estate company request for designing and manufacturing of an in door CO 2 monitoring system The system consists in a wireless sensor network ( whose nodes are connected in a star configuration The work describes the applied research for the design of a cost effective CO 2 remote monitoring system for indoor use in office buildings which are supposed to have more than 100 rooms, based on the analysis of CO 2 sensors solutions already existing on the market Experiments with the system were performed in the laboratory and at a site at several kilometres distance.

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