Fabrication of a Capacitive Relative Humidity Sensor Using Aluminum Thin Films Deposited on Etched Printed Circuit Board

A capacitive humidity-sensing device was created by thermal evaporation of 99.999% aluminum. The substrate used for the coating was etched double-sided printed circuit board. The etched printed circuit board serves as the dielectric of the capacitor while the aluminum thin films deposited on either side serve as the plates of the capacitor. The capacitance was measured before and after exposure to humidity. The device was then calibrated by comparing the readings of capacitance with that of the relative humidity sensor of the Vernier LabQuest2. It was found that there is a linear relationship between the capacitance and relative humidity given by the equation C=1.418RH+29.139 where C is the capacitance and RH is the relative humidity. The surface of the aluminum films is porous and it is through these pores that water is adsorbed and capillary condensation occurs, thereby causing the capacitance to change upon exposure to humidity

Pre‐conceptions of Newton’s Laws of Motion of Students in Introductory Physics

The Force and Motion Conceptual Evaluation (FMCE) developed by R.K. Thornton and D. R. Sokoloff was utilized to evaluate the conceptual understanding of Newton’s Laws of Motion. The test was administered to 100 freshman university students enrolled in introductory physics courses. The aim is to find out the conceptual understanding of the students prior to university level instruction. Results show that the Aristotelian notion prevails despite having taken physics in their senior year in high school. This study emphasizes the importance of training high school physics teachers and the significance of a change in the teaching techniques for university level introductory physics

Surface Imaging of Cold DC Magnetized Air Plasma Treated Poly (dimethyl siloxane) Surfaces

The surface morphology of poly(dimethyl siloxane) surfaces treated with cold dc magnetized air plasma had been investigated via scanning electron microscopy. The treatment parameters involved in the study were sample-cathode distance, discharge power, and discharge pressure. The plasma treated PDMS surfaces exhibit a variety of surface structures ranging from cracked film morphology to the presence of disordered buckling and aligned, corrugation depending on the treatment parameter studied

Effect of Atmospheric Plasma Treatment on Seed Germination of Rice (Oryza sativa L.)

Multiple methods of improving plant development have been utilized over the past decades. Despite these improvements, there still exists a need for better planting methods due to the increasing population of a global community. Studies have reported that plasma treatment affects the growth and germination of a variety of plant species, including a multitude of grains which often takes the bulk in the diet of the average human being. This study explores the effect of atmospheric air plasma jet treatment on the seed germination of rice (Oryza sativa L.). The seeds were treated using an atmospheric air plasma jet for 1, 2, and 3 s. The effect of plasma exposure shows a reduction of trichomes on the surface of the seed. This caused a possible increase in wettability which significantly affected the seed germ length but did not affect the seed germination count after the germination period of 72 h

Sustained hydrophilicity of plasma-treated PDMS surfaces by water immersion

We demonstrate surface treatment of PDMS by direct current (dc) magnetron Argon plasma to examine the effects of plasma exposure and water immersion on the surface properties of PDMS. Results of contact angle measurements and FTIR-ATR spectroscopy show that plasma treatment led to significant hydrophilicity on the PDMS surface. Water-immersed plasma treated samples were found to sustain a more hydrophilic surface compared to air-stored samples despite having longer aging time. The study proved water to be an effective hydrophobic recovery retardant for plasma-treated PDMS surfaces

Synthesis of Fluorescent Carbon via Atmospheric Pressure Plasma Pyrolysis of Waste Expanded Polystyrene

The lack of proper waste management systems in various countries often results in a continual volume increase of plastic waste which when left unkempt may be detrimental to the environment. Plasma pyrolysis provides a possible solution to the problem of increasing polymeric waste by transforming polymers into reusable hydrocarbons and residual carbon at much lower temperatures compared to high temperature pyrolysis methods. The study analyses the resultant carbon as a result of the plasma pyrolysis of waste expanded polystyrene (WEPS) via industrial nitrogen plasma exposure for 20 min under varied flow rates (10, 13, 15 standard cubic feet per hour). From the optical emission spectroscopy spectra, the presence of C, O, and N ions were identified which indicates the possible presence of light-weight hydrocarbons as well as CO in the plasma. The residual solids were analyzed using X-ray diffraction, scanning electron microscope, and Raman spectroscopy which showed that the process was able to successfully produce carbon at lower temperatures and fluorescent carbon at higher temperatures from the decomposition of WEPS

Assessing microalgal biodiesel sustainability via MCI and LCA frameworks

Natural resource extraction have increased three folds during the last four decades. Of which, economic development has been its main driving factor. Ensuring material security and environmental sustainability is of utmost importance for a sustainable economic growth. Circular economy addresses this challenge, via promoting reutilization of a product\u27s components and promoting value durability. It promotes a closed loop economy which reduces virgin resource extraction and promotes recycling. The energy requirement for this economic system will require energy sources of high recycling potential. A good candidate may be found in biofuels, because of its quick reutilization of the atmospheric carbon dioxide. Currently, one of the most promising feedstocks for biofuels is microalgae. It has the capacity to grow in non-arable land and produce significant amounts of oil per hectare. Several studies have assessed the environmental impact of its production, but none has considered its applicability in a circular economy. In this paper, we propose the frameworks of life cycle assessment and the material circularity indicator by the Ellen MacArthur foundation to assess the applicability of microalgal biodiesel in a circular economy. We utilized the life cycle assessment frameworks in assessing the feedstock\u27s impact to global warming, resource depletion, and bulk waste, while the material circularity indicator is utilized to quantify its reutilization. Comparison was carried out to jatropha biodiesel as a reference feedstock due to its similar popularity. The results of the study can provide new perspectives on how to promote microalgal biodiesel in a circular economy. © 2018 IEEE. b

A fuzzy multi-regional input-output optimization model for biomass production and trade under resource and footprint constraints

Interest in bioenergy in recent years has been stimulated by both energy security and climate change concerns. Fuels derived from agricultural crops offer the promise of reducing energy dependence for countries that have traditionally been dependent on imported energy. Nevertheless, it is evident that the potential for biomass production is heavily dependent on the availability of land and water resources. Furthermore, capacity expansion through land conversion is now known to incur a significant carbon debt that may offset any benefits in greenhouse gas reductions arising from the biofuel life cycle. Because of such constraints, there is increasing use of non-local biomass through regional trading. The main challenge in the analysis of such arrangements is that individual geographic regions have their own respective goals. This work presents a multi-region, fuzzy input-output optimization model that reflects production and consumption of bioenergy under land, water and carbon footprint constraints. To offset any local production deficits or surpluses, the model allows for trade to occur among different regions within a defined system; furthermore, importation of additional biofuel from external sources is also allowed. Two illustrative case studies are given to demonstrate the key features of the model. © 2011 Elsevier Ltd