Investigation and performance optimization of mesh networking in Zigbee

The aim of this research paper is to perform a detailed investigation and performance optimization of mesh networking in Zigbee. ZigBee applications are open and global wireless technology that are based on IEEE 802.15.4 standard, it is used for sense and control in many fields like, military, commercial, industrial and medical applications. Extending ZigBee lifetime is a high demand in many ZigBee networks industry and applications, and since the lifetime of ZigBee nodes depends mainly on batteries for their power, the desire for developing a scheme or methodology that support power management and saving battery lifetime is of a great requirement. In this research work, a power sensitive routing Algorithm is proposed Power Sensitive Ad hoc On-Demand (PS-AODV) to develop protocol scheme and methodology of existing on-demand routing protocols, by introducing an algorithm that manages ZigBee operations and construct the route from trusted active nodes. Furthermore, many aspects of routing protocol in ZigBee mesh networks have been researched to concentrate on route discovery, route maintenance, neighbouring table, and shortest paths. PS-AODV routing algorithm is used in two different ZigBee mesh networks, with two different coordinator locations, one used at the centre and the other one at the corner of the networks. The extracted results conclude a better network operation for the coordinator located at the centre with an increase in the network lifetime around 20% percentage, and saved about 32.7% of delay time compare to AODV

Assessment of Genetic Biodiversity of Several Traits Using SSR Markers in Rice (Oryza sativa L.)

Eight primers (RM 315, RM 318, RM 166, RM 302, RM 201, RM 234, RM 526 and RM 144) revealed different levels of polymorphism to tag the related traits of interest as tolerant to abiotic stress, resistant to biotic stress and yield-related traits. Two primers (RM 190 and RM 278) were monomorphic. The percentage of the polymorphism was nearly 80 %. The size of detected fragments ranged from 105–325 bp. A total of 186 bands were scored from the amplification products with the ten SSR primers. Genetic diversity analyses were conducted on the basis of the scores with 176 unique bands. Phylogenic tree for the fifteen rice accessions from each group were established according to the molecular data and based on ten SSRs. A marked genetic diversity was observed in these innovative accessions (Sakha 101, IR 03N137, IR 83142-12, IR 87856-10-AJY-1-B, HHZ 12-Y4-DT1-Y2 and IR 1552), which revealed higher levels of diversity and hence can be used as donors for the effective conservation, utilization and providing favorable genes in rice breeding programs

Optimisation of a novel hot air contactless single incremental point forming of polymers

This study presents a new contactless sheet forming method that utilises hot air as a forming tool to address tool wear challenges in single-point incremental forming. Experiments were conducted on a 3-axis CNC machine equipped with a hot air nozzle on a polycarbonate sheet. A design of experiment (DOE) approach was employed, evaluating five control factors: air pressure, air temperature, feed rate, tool offset, and step down. The evaluation criteria for the formed sheets are profile variation, thickness variation, and surface roughness. The results indicate that air temperature and feed rate have the most significant influence on the deformation process. Additionally, air pressure and feed rate substantially impact both thickness variation and surface roughness of the formed material. To optimise the process parameters for high-quality forming, a prediction model is developed. The optimised process shows good agreement with the predicted model regarding profile and thickness variations. However, it does not align with surface roughness due to the stepwise nature and inherent waviness of the contactless forming technique. This study offers a promising approach for developing innovative contactless forming techniques using hot pressurised air as a forming tool. The proposed technique has the potential to significantly reduce tool wear and lubrication requirements

Porosity, cracks, and mechanical properties of additively manufactured tooling alloys: A review

Additive manufacturing (AM) technologies are currently employed for the manufacturing of completely functional parts and have gained the attention of high-technology industries such as the aerospace, automotive, and biomedical fields. This is mainly due to their advantages in terms of low material waste and high productivity, particularly owing to the flexibility in the geometries that can be generated. In the tooling industry, specifically the manufacturing of dies and molds, AM technologies enable the generation of complex shapes, internal cooling channels, the repair of damaged dies and molds, and an improved performance of dies and molds employing multiple AM materials. In the present paper, a review of AM processes and materials applied in the tooling industry for the generation of dies and molds is addressed. AM technologies used for tooling applications and the characteristics of the materials employed in this industry are first presented. In addition, the most relevant state-of-the-art approaches are analyzed with respect to the process parameters and microstructural and mechanical properties in the processing of high-performance tooling materials used in AM processes. Concretely, studies on the additive manufacturing of ferrous (maraging steels and H13 steel alloy) and non-ferrous (Stellite alloys and WC alloys) tooling alloys are also analyzed

Hot-air contactless single-point incremental forming

Single-point incremental forming (SPIF) has emerged as a time-efficient approach that offers increased material formability compared to conventional sheet-metal forming techniques. However, the physical interaction between the forming tool and the sheet poses challenges, such as tool wear and formability limits. This study introduces a novel sheet-forming technique called contactless single-point incremental forming (CSPIF), which uses hot compressed air as a deformation tool, eliminating the requirement for physical interaction between the sheet and a rigid forming tool. In this study, a polycarbonate sheet was chosen as the case-study material and subjected to the developed CSPIF. The experiments were carried out at an air temperature of 160 °C, air pressure of 1 bar, a nozzle speed of 750 mm/min, and a step-down thickness of 0.75 mm. A Schlieren setup and a thermal camera were used to visualize the motion of the compressed hot air as it traveled from the nozzle to the sheet. The results showed that the CSPIF technique allowed for the precise shaping of the polycarbonate sheet with minimal springback. However, minor deviations from the designed profile were observed, primarily at the starting point of the nozzle, which can be attributed to the bending effects of the sample. In addition, the occurrence of sheet thinning and material buildup on the deformed workpiece was also observed. The average surface roughness (Ra) of the deformed workpiece was measured to be 0.2871 micron

Workers’ Remittances in Yemen: Macroeconomic Determinants and Impact on Economic Growth

This study aims to examine the determinants of workers’ remittances and their impact on economic growth in Yemen. Autoregressive Distributed Lag (ARDL) bounds test to co-integration and error correction model (ECM) were applied on data covering the period from 1990 to 2014. According to the model of remittances determinants, workers’ remittances in Yemen respond to the macroeconomic conditions of both the home and host countries. It is found that, in the long-run, migrant stock and income level at the host countries are positively and strongly influence remittances level, with a feeble impact of domestic inflation rates. The effect of the home country’s income seems to be positive but insignificant in explaining the behaviour of remittances level. The model of economic growth suggests that, in the long run, the impact of workers’ remittances appears to be positive and moderate with positive and stronger influences observed for financial development and official development assistance. Accordingly, it is recommended that a lesser weight should be given to remittances in the strategic planning process, taking into consideration the increasing potentials of the conditions in the neighbouring host countries to be changed. In addition, using remittances as a means of economic growth can be enhanced by encouraging migrants to direct their savings towards productive investment activities, and via formal channels

4D Printing of origami structures for minimally invasive surgeries using functional scaffold

Origami structures have attracted attention in biomedical applications due to their ability to develop surgical tools that can be expanded from a minimal volume to a larger and functional device. On the other hand, four-dimensional (4D) printing is an emerging technology, which involves 3D printing of smart materials that can respond to external stimuli such as heat. This short communication introduces the proof of concept of merging origami and 4D printing technologies to develop minimally invasive delivery of functional biomedical scaffolds with high shape recovery. The shape-memory effect (SME) of the PLA filament and the origami designs were also assessed in terms of deformability and recovery rate. The results showed that herringbone tessellation origami structure combined with internal natural cancellous bone core satisfies the design requirement of foldable scaffolds. The substantial and consistent SME of the 4D printed herringbone tessellation origami, which exhibited 96% recovery compared to 61% for PLA filament, was the most significant discovery of this paper. The experiments demonstrated how the use of 4D printing in situ with origami structures could achieve reliable and repeatable results, therefore conclusively proving how 4D printing of origami structures can be applied to biomedical scaffolds

High-Field fMRI for Human Applications: An Overview of Spatial Resolution and Signal Specificity

In the last decade, dozens of 7 Tesla scanners have been purchased or installed around the world, while 3 Tesla systems have become a standard. This increased interest in higher field strengths is driven by a demonstrated advantage of high fields for available signal-to-noise ratio (SNR) in the magnetic resonance signal. Functional imaging studies have additional advantages of increases in both the contrast and the spatial specificity of the susceptibility based BOLD signal. One use of this resultant increase in the contrast to noise ratio (CNR) for functional MRI studies at high field is increased image resolution. However, there are many factors to consider in predicting exactly what kind of resolution gains might be made at high fields, and what the opportunity costs might be. The first part of this article discusses both hardware and image quality considerations for higher resolution functional imaging. The second part draws distinctions between image resolution, spatial specificity, and functional specificity of the fMRI signals that can be acquired at high fields, suggesting practical limitations for attainable resolutions of fMRI experiments at a given field, given the current state of the art in imaging techniques. Finally, practical resolution limitations and pulse sequence options for studies in human subjects are considered

Heavy Metals Pollution in the Highway – Side Soil around Baghdad City

The study aimed to assessment of pollution status by heavy metals Cadmium, Lead, Zinc, and Nickel for Soils in surrounding highway of Baghdad city, evaluate the relation between heavy metals concentration in soil, and study effect of distance from pollution source. Study area was include high express way surrounded Baghdad city, starting from main gate in Yusufiyah and ended in Al-Fedaa Company in 43 km distance approximately. Soil samples were collected from 5 locations with 9 km interval between location and other. Soil Samples were taken from surface layer (0 – 25) cm depth, at both road sides (back and forth) within 4 distances (1.5, 10, 25, and 60 m) from each roads sides, and another samples were taken from 2 km distance from road sides, to comparison 3 samples for same depth. Results that have been achieved by this study can summarize as following: Results showed that heavy metals concentrations in soil samples along highway which surrounded Baghdad city took the following order Ni > Zn > Pb > Cd And all was higher than their concentration in comparison soils. The concentrations of Cadmium were ranged between 0.21– 3.93 mg kg-1 in soil samples at high way, In general, the concentrations of Cadmium were decreased with distance from road sides, while the higher values were recorded within first and second distances 1.5 and 10 m.The concentrations of Lead were ranged between 36.0 – 129.0 mg kg-1 in soil samples at high way, while the changes in Lead concentrations in some soil locations was refered to effect of environmental changes, like direction and speed of wind.Zinc concentrations were ranged between 240.0 – 380.0 mg kg-1 in soil samples at high way, while the increasing of Zinc concentrations in Al-Daura soil samples spite of low traffic jams was due to close located to Al-Daura refinery.Nickel concentrations were ranged between 95.0 – 248.0 mg k-1 in soil samples at high way, also the concentrations of Nickel were increased in Mohammed Al-Qassim highway soil samples while others heavy metals (Zn, Pb, and Cd) were decreased and this can be attributed to another Nickel source in that location. Keywords: Pollution, Heavy metals, Soil, Air, Vehicular Traffic, Traffic density, Baghdad. Iraq, AAS