Ultra-high frequency, high Q/volume micromechanical resonators in a planar AlN phononic crystal

Citation: Baboly, M. G., Alaie, S., Reinke, C. M., El-Kady, I., & Leseman, Z. C. (2016). Ultra-high frequency, high Q/volume micromechanical resonators in a planar AlN phononic crystal. Journal of Applied Physics, 120(3), 5. doi:10.1063/1.4958671This paper presents the first design and experimental demonstration of an ultrahigh frequency complete phononic crystal (PnC) bandgap aluminum nitride (AlN)/air structure operating in the GHz range. A complete phononic bandgap of this design is used to efficiently and simultaneously confine elastic vibrations in a resonator. The PnC structure is fabricated by etching a square array of air holes in an AlN slab. The fabricated PnC resonator resonates at 1.117 GHz, which corresponds to an out-of-plane mode. The measured bandgap and resonance frequencies are in very good agreement with the eigen-frequency and frequency-domain finite element analyses. As a result, a quality factor/volume of 7.6 x 10(17)/m(3) for the confined resonance mode was obtained that is the largest value reported for this type of PnC resonator to date. These results are an important step forward in achieving possible applications of PnCs for RF communication and signal processing with smaller dimensions. Published by AIP Publishing

The long-term mental health outcome of adolescent with depression and alcohol abuse comorbidity

Abstract Background Alcohol abuse often co-occurs with adolescent depression and about 1-2% suffer from the dual diagnosis in adolescence. This group is often undertreated or receive inadequate treatment for either of the conditions. Both conditions affect the developing brain and poor long-term outcome might be a potential risk. Yet, long-term follow-up studies are scarce. The aim of this study was to analyse if adolescent depression and alcohol abuse predict poorer mental health in adulthood compared to individuals without either or both conditions. Methods A community-based sample of individuals with adolescent depression in 1991-93 and matched non-depressed peers were followed up using a structured diagnostic interview after 15 years. The participation rate was 65% (depressed n = 227; non-depressed controls n = 155). Information on alcohol abuse in adolescence was collected at baseline with a structured interview. The outcome was mental disorders between the ages 19-31 years; information on depression and alcohol abuse was collected at the follow-up with a structured diagnostic interview. The statistical method used was binary logistic regression. Results Adolescents with depression and alcohol abuse had an excess risk of recurrence of depression (OR 2.12, p &amp;lt; 0.05) and alcohol abuse (OR 6.72, p &amp;lt; 0.01) in adulthood, compared with adolescents with depression only, even when adjusted for confounders. Adolescents with alcohol abuse only had not significantly worse long-term outcome compared with their healthy peers. Conclusions The co-occurrence of depression and alcohol abuse in adolescence is associated with long-lasting health consequences compared to either condition alone. This finding indicates that there is a need to prioritize this group of patients that is at risk of suboptimal treatment, and to further develop effective treatment adjusted to the co-occurring condition. Key messages The co-occurrence of adolescent depression and alcohol abuse has long lasting mental health consequences compared to either condition alone. Improved treatment methods are important for this group of adolescents. </jats:sec

The long-term mental health outcome of adolescent with depression and alcohol abuse comorbidity

Abstract Background Alcohol abuse often co-occurs with adolescent depression and about 1-2% suffer from the dual diagnosis in adolescence. This group is often undertreated or receive inadequate treatment for either of the conditions. Both conditions affect the developing brain and poor long-term outcome might be a potential risk. Yet, long-term follow-up studies are scarce. The aim of this study was to analyse if adolescent depression and alcohol abuse predict poorer mental health in adulthood compared to individuals without either or both conditions. Methods A community-based sample of individuals with adolescent depression in 1991-93 and matched non-depressed peers were followed up using a structured diagnostic interview after 15 years. The participation rate was 65% (depressed n = 227; non-depressed controls n = 155). Information on alcohol abuse in adolescence was collected at baseline with a structured interview. The outcome was mental disorders between the ages 19-31 years; information on depression and alcohol abuse was collected at the follow-up with a structured diagnostic interview. The statistical method used was binary logistic regression. Results Adolescents with depression and alcohol abuse had an excess risk of recurrence of depression (OR 2.12, p < 0.05) and alcohol abuse (OR 6.72, p < 0.01) in adulthood, compared with adolescents with depression only, even when adjusted for confounders. Adolescents with alcohol abuse only had not significantly worse long-term outcome compared with their healthy peers. Conclusions The co-occurrence of depression and alcohol abuse in adolescence is associated with long-lasting health consequences compared to either condition alone. This finding indicates that there is a need to prioritize this group of patients that is at risk of suboptimal treatment, and to further develop effective treatment adjusted to the co-occurring condition. Key messages The co-occurrence of adolescent depression and alcohol abuse has long lasting mental health consequences compared to either condition alone. Improved treatment methods are important for this group of adolescents

COD removal from gasfield produced water using photoelectrocatalysis process on coil type microreactor

A special type of reactor with a high active surface-to-volume ratio was used for investigation of organic pollutants degradation from a gasfield produced water by photoelectrocatalysis process. The GC–MS analysis showed that there were more than 50 organic substances in this wastewater; therefore, COD was considered as the target parameter for studying. A simple evaporation process used for decreasing high TDS of the wastewater reduced its electrical conductivity from 6300 μS/cm to 1100 μS/cm and also initial COD decreased simultaneously from 9500 mg/L to 750 mg/L. Distilled wastewater from the evaporation process was treated again by the photoelectrocatalysis process using a coil type microreactor, and its COD dropped off to 143 mg/L. Instead of usual semiconductors in photoelectrocatalysis like TiO2, boron carbon nitride (BCN) nanosheets are used as a photocatalyst in this study. Investigating the impact of different parameters on COD removal efficiency showed that the greatest COD removal efficiency (81%) was obtained at residence time 15 min, pH = 3, applied cell voltage 20 V, electrical conductivity = 2500 μS/cm and H2O2 concentration of 8 mM. © 2021 The Korean Society of Industrial and Engineering Chemistr

Use of modified and petroleum -impregnated bentonite mulch as an eco-friendly stabilizer of wind erodible sands

This study aimed to develop a method for the management of petroleum pollutants released into the environment using modified bentonite and to evaluate the use of petroleum-impregnated modified bentonite, as an eco-friendly and resistant mulch to stabilize mobile sands exposed to wind erosion. Bentonite was modified using hexa-decyl-tri-methyl-ammonium bromide to increase its capacity for petroleum adsorption. The resistivity to breakdown of the produced mulch was determined against wind, runoff, and by drainage water caused by simulated rainfall. Results showed that the basal spacing of the modified bentonite increased 162% compared to unmodified bentonite and it was able to adsorb petroleum, 5 times its base weight. The produced mulch was resistant against wind flows up to 16.7 m s−1 with no soil loss during 5 min, while the untreated sandy soil started to move at a threshold speed of 10.3 m s−1 (with a soil loss rate of 53 g m−2 s−1) and the tray of soil was fully eroded after 135 s. Analysis of the drainage waters which passed through the mulch showed that mulch 2 (ratio 5:1, sandy soil: modified clay + unmodified clay (1:1) mixed by petroleum) retained more polycyclic aromatic hydrocarbons compounds, compared to mulches 1 (ratio of 5:1 sandy soil: unmodified bentonite mixed with petroleum) and 3 (ratio 5:1:0.5, sandy soil: unmodified clay: modified clay mixed by petroleum). Analysis of the runoff water samples also showed that PAHs retention in mulch 2 is significantly higher than the amounts retained by mulches 1 and 3.No Full Tex