Resistive switching in FTO/CuO-Cu2O/Au memory devices

Memristors are considered to be next-generation non-volatile memory devices owing to their fast switching and low power consumption. Metal oxide memristors have been extensively investigated and reported to be promising devices, although they still suffer from poor stability and laborious fabrication process. Herein, we report a stable and power-efficient memristor with novel heterogenous electrodes structure and facile fabrication based on CuO-Cu2O complex thin films. The proposed structure of the memristor contains an active complex layer of cupric oxide (CuO) and cuprous oxide (Cu2O) sandwiched between fluorine-doped tin oxide (FTO) and gold (Au) electrodes. The fabricated memristors demonstrate bipolar resistive switching (RS) behavior with a low working voltage (~1 V), efficient power consumption, and high endurance over 100 switching cycles. We suggest the RS mechanism of the proposed device is related to the formation and rupture of conducting filaments inside the memristor. Moreover, we analyze the conduction mechanism and electron transport in the active layer of the device during the RS process. Such a facile fabricated device has a promising potential for future memristive applications

Air quality in Mecca and surrounding holy places in Saudi Arabia during Hajj: initial survey.

The Arabian Peninsula experiences severe air pollution, the extent and sources of which are poorly documented. Each year in Saudi Arabia this situation is intensified during Hajj, the Holy Pilgrimage of Islam that draws millions of pilgrims to Mecca. An initial study of air quality in Mecca and surrounding holy sites during the 2012 Hajj (October 24-27) revealed strongly elevated levels of the combustion tracer carbon monoxide (CO, up to 57 ppmv) and volatile organic compounds (VOCs) along the pilgrimage route-especially in the tunnels of Mecca-that are a concern for human health. The most abundant VOC was the gasoline evaporation tracer i-pentane, which exceeded 1200 ppbv in the tunnels. Even though VOC concentrations were generally lower during a follow-up non-Hajj sampling period (April 2013), many were still comparable to other large cities suffering from poor air quality. Major VOC sources during the 2012 Hajj study included vehicular exhaust, gasoline evaporation, liquefied petroleum gas, and air conditioners. Of the measured compounds, reactive alkenes and CO showed the strongest potential to form ground-level ozone. Because the number of pilgrims is expected to increase in the future, we present emission reduction strategies to target both combustive and evaporative fossil fuel sources

Climate Change and Water Scarcity: The Case of Saudi Arabia

Background: Climate change is expected to bring increases in average global temperatures (1.4°C–5.8°C [34.52°F–42.44°F] by 2100) and precipitation levels to varying degrees around the globe. The availability and quality of water will be severely affected, and public health threats from the lack of this valuable resource will be great unless water-scarce nations are able to adapt. Saudi Arabia provides a good example of how the climate and unsustainable human activity go hand in hand in creating stress on and depleting water resources, and an example for adaptation and mitigation. Method: A search of the English literature addressing climate change, water scarcity, human health, and related topics was conducted using online resources and databases accessed through the University at Albany, State University of New York library web page. Results: Water scarcity, which encompasses both water availability and water quality, is an important indicator of health. Beyond drinking, water supply is intimately linked to food security, sanitation, and hygiene, which are primary contributors to the global burden of disease. Poor and disadvantaged populations are the ones who will suffer most from the negative effects of climate change on water supply and associated human health issues. Examples of adaptation and mitigation measures that can help reduce the strain on conventional water resources (surface waters and fossil aquifers or groundwater) include desalination, wastewater recycling and reuse, and outsourcing food items or “virtual water trade.” These are strategies being used by Saudi Arabia, a country that is water poor primarily due to decades of irresponsible irrigation practices. The human and environmental health risks associated with these adaptation measures are examined. Finally, strategies to protect human health through international collaboration and the importance of these efforts are discussed. Conclusion: International, multidisciplinary cooperation and collaboration will be needed to promote global water security and to protect human health, particularly in low-income countries that do not have the resources necessary to adapt on their own

Characterization of carbon monoxide, methane and nonmethane hydrocarbons in emerging cities of Saudi Arabia and Pakistan and in Singapore

We investigate the composition of 63 C2-C10 nonmethane hydrocarbons (NMHCs), methane (CH4) and carbon monoxide (CO), in Jeddah, Mecca, and Madina (Saudi Arabia), in Lahore, (Pakistan), and in Singapore. We established a database with which to compare and contrast NMHCs in regions where ambient levels and emissions are poorly characterized, but where conditions are favorable to the formation of tropospheric ozone, and where measurements are essential for improving emission inventories and modeling. This dataset will also serve as a base for further analysis of air pollution in Western Saudi Arabia including, but not limited to, the estimation of urban emissions and long range pollution transport from these regions. The measured species showed enhanced levels in all Saudi Arabian cities compared to the local background but were generally much lower than in Lahore. In Madina, vehicle exhaust was the dominant NMHC source, as indicated by enhanced levels of combustion products and by the good correlation between NMHCs and CO, while in Jeddah and Mecca a combination of sources needs to be considered. Very high NMHC levels were measured in Lahore, and elevated levels of CH4 in Lahore were attributed to natural gas. When we compared our results with 2010 emissions from the MACCity global inventory, we found discrepancies in the relative contribution of NMHCs between the measurements and the inventory. In all cities, alkenes (especially ethene and propene) dominated the hydroxyl radical (OH) reactivity (kOH) because of their great abundance and their relatively fast reaction rates with OH

Cytogenetics and Consequences of Polyploidization on Different Biotic-Abiotic Stress Tolerance and the Potential Mechanisms Involved

The application of polyploidy in sustainable agriculture has already brought much appreciation among researchers. Polyploidy may occur naturally or can be induced in the laboratory using chemical or gaseous agents and results in complete chromosome nondisjunction. This comprehensive review described the potential of polyploidization on plants, especially its role in crop improvement for enhanced production and host-plant resistance development against pests and diseases. An in-depth investigation on techniques used in the induction of polyploidy, cytogenetic evaluation methods of different ploidy levels, application, and current research trends is also presented. Ongoing research has mainly aimed to bring the recurrence in polyploidy, which is usually detected by flow cytometry, chromosome counting, and cytogenetic techniques such as fluorescent in situ hybridization (FISH) and genomic in situ hybridization (GISH). Polyploidy can bring about positive consequences in the growth and yield attributes of crops, making them more tolerant to abiotic and biotic stresses. However, the unexpected change in chromosome set and lack of knowledge on the mechanism of stress alleviation is hindering the application of polyploidy on a large scale. Moreover, a lack of cost-benefit analysis and knowledge gaps on the socio-economic implication are predominant. Further research on polyploidy coupling with modern genomic technologies will help to bring real-world market prospects in the era of changing climate. This review on polyploidy provides a solid foundation to do next-generation research on crop improvement

The Investigation of the Relationship Between Emotional Engagement and Creativity

Background - One of the most critical challenges in engineering education is improving students’ divergent thinking skills. Usually, we observe students’ fixating on only one single solution for engineering problems. However, their ability to think outside the box and provide alternative solutions should be developed. Research shows that engagement may foster the development of thoughts and boost creativity. Purpose/Hypothesis – Our aim was to investigate students’ engagement with tasks that inspire different facets of creativity (verbal, numeric, and visual). Considering the role of demographics in student engagement, we explored the relationship between their engagement level and demographic traits such as gender, major, age, grades (GPA), and the languages they know besides their native tongue. Design/Method - We utilized electrodermal activity (EDA) sensors, a well-documented proxy of emotional engagement, to measure students’ engagement level while performing tasks that inspire different facets of creativity (verbal, numeric, and visual). Due to the non-normal distribution of the data, non-parametric statistical tests were conducted considering engagement as a dependent variable and demographic traits as independent variables. Results - Statistically significant differences in students’ engagement when exposed to creativity inspired tasks were observed. However, no association between demographics and engagement levels were detected. Conclusions - The results of the study may support educators in designing the instructional materials considering creativity-inspired activities so that students’ engagement level can be increased. Further, results from this study can inform experimental designs, specifically participant selection, in engagement focused studies

Propiedades físico-químicas de mezclas de oleina de palma con otros aceites vegetales

Palm oil (olein) was blended with other edible oils for the enhancement of its market acceptability in terms of melting point depression and shelf life. The physico-chemical properties like viscosity, density, melting behavior, peroxide value (PV), saponification value (SV) and iodine value (IV) of four different binary blends with four vegetable oils were evaluated. Palm olein was found to be more stable against rancidity than the other oils. For the stability against oxidation and melting point depression the palm olein-canola (PO/CO) blend was found to be better than the others. The Differential Scanning Calorimeter (DSC) thermogram of the melting behavior of the blends traces some new polymorphs of the triglyceride. This study will help the oil producing industry to find out the most economically viable oil blends for cooking purposes, with maximum nutrition as well as desirable physico-chemical properties.Aceite de palma (oleína) fue mezclada con otros aceites comestibles para aumentar su aceptabilidad en el mercado en términos de descenso del punto de fusión y mejora de su almacenamiento. Las propiedades físico-químicas tales como viscosidad, densidad, comportamiento en la fusión, valor de peróxidos (PV), valor de saponificación (SV) e índice de yodo (IV) de cuatro diferentes mezclas binarias con cuatro aceites vegetales fueron evaluadas. La oleína de palma fue más estable frente a la rancidez que otros aceites. En la estabilidad frente la oxidación y el descenso del punto de fusión, la mezcla de oleína de palma/canola (PO/CO) fue mejor que las otras. Los termogramas del calorímetro diferencial de barrido (DSC) referidos al comportamiento de fusión de las mezclas indican algunos nuevos polimorfismos de los triglicéridos. Este estudio podría ayudar a las empresas que elaboran aceites a encontrar los aceites económicamente más viables para cocinar, con buenas propiedades nutricionales, así como con unas propiedades físico-químicas deseables