Graphene based flexible electrochromic devices

Graphene emerges as a viable material for optoelectronics because of its broad optical response and gate-tunable properties. For practical applications, however, single layer graphene has performance limits due to its small optical absorption defined by fundamental constants. Here, we demonstrated a new class of flexible electrochromic devices using multilayer graphene (MLG) which simultaneously offers all key requirements for practical applications; high-contrast optical modulation over a broad spectrum, good electrical conductivity and mechanical flexibility. Our method relies on electro-modulation of interband transition of MLG via intercalation of ions into the graphene layers. The electrical and optical characterizations reveal the key features of the intercalation process which yields broadband optical modulation up to 55 per cent in the visible and near-infrared. We illustrate the promises of the method by fabricating reflective/transmissive electrochromic devices and multi-pixel display devices. Simplicity of the device architecture and its compatibility with the roll-to-roll fabrication processes, would find wide range of applications including smart windows and display devices. We anticipate that this work provides a significant step in realization of graphene based optoelectronics

study on the chopping and mixing of cotton stalks with soil

This study examined the methods adopted in Turkey to remove cotton stalks remaining in the field after the cotton harvest and quantified the efficiency of different mechanized stalk choppers. In this study, theperformance of three different types of cotton stalk choppers was assessed (chain-type, splined-type and vertical-blade rotating dredge). Field experiments were conducted with each type to determine the proportion of non-uprooted cotton stalks; mean “post-chopping height” of the stalks, measured from soil surface; and the frequency distribution of the piece length of the stalks scattered around the field or mixed with soil after chopping. In addition, the workforce requirement, using time and fuel consumption of each type of chopper was calculated. The lowest fuel consumption was recorded by the chain-type stalk chopper (5.0 l/da), while the highest fuel consumption was recorded by the vertical-blade rotatingdredge (7.1 l/ha). The largest “mean post-chopping piece size” was achieved by the vertical-blade rotating dredge plus geared cylinder (28.36 cm), while the smallest size was recorded by the splinedtype stalk chopper (13.38 cm). The highest rate of stalks mixed with the soil after chopping was achieved by the splined-type stalk copper (92.5%)

Training the brain to overcome the effect of aging on the human eye

Presbyopia, from the Greek for aging eye, is, like death and taxes, inevitable. Presbyopia causes near vision to degrade with age, affecting virtually everyone over the age of 50. Presbyopia has multiple negative effects on the quality of vision and the quality of life, due to limitations on daily activities – in particular, reading. In addition presbyopia results in reduced near visual acuity, reduced contrast sensitivity, and slower processing speed. Currently available solutions, such as optical corrections, are not ideal for all daily activities. Here we show that perceptual learning (repeated practice on a demanding visual task) results in improved visual performance in presbyopes, enabling them to overcome and/or delay some of the disabilities imposed by the aging eye. This improvement was achieved without changing the optical characteristics of the eye. The results suggest that the aging brain retains enough plasticity to overcome the natural biological deterioration with age

Graphene-enabled electrically switchable radar-absorbing surfaces

Radar-absorbing materials are used in stealth technologies for concealment of an object from radar detection. Resistive and/or magnetic composite materials are used to reduce the backscattered microwave signals. Inability to control electrical properties of these materials, however, hinders the realization of active camouflage systems. Here, using large-area graphene electrodes, we demonstrate active surfaces that enable electrical control of reflection, transmission and absorption of microwaves. Instead of tuning bulk material property, our strategy relies on electrostatic tuning of the charge density on an atomically thin electrode, which operates as a tunable metal in microwave frequencies. Notably, we report large-area adaptive radar-absorbing surfaces with tunable reflection suppression ratio up to 50 dB with operation voltages <5 V. Using the developed surfaces, we demonstrate various device architectures including pixelated and curved surfaces. Our results provide a significant step in realization of active camouflage systems in microwave frequencies. © 2015 Macmillan Publishers Limited. All rights reserved

DJELOVANJE BAKTERIJSKOG CJEPIVA HOMOFERMENTACIJSKE MLIJEČNE KISELINE NA FERMENTACIJU I AEROBNU STABILNOST KUKURUZNE SILAŽE NAKNADNE SJETVE

This study was carried out to determine the effects of homofermentative lactic acid bacterial inoculant on the fermentation and aerobic stability of second crop maize silages. Maize was harvested at the milk stage. Inoculant -1174 (Pioneer®,USA) was used as homofermentative lactic acid bacterial inculant. Inoculant was applied 6.00 log10 cfu/g silage levels. Silages with no additive served as controls. After treatment, the chopped maize was ensiled in the PVC type laboratory silos. Three silos for each group were sampled for chemical and microbiological analysis on days 2, 4, 7, 14, 21, 28 and 56 after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 14 days. Neither inoculant improved the fermentation parameters of second crop maize silages. At the end of the ensiling period, inoculant increased lactobacilli and decreased yeast and mold numbers of silages. Inoculant treatment did not affect aerobic stability of silages.Svrha rada je bila utvrditi djelovanje bakterijskog cjepiva homofermentacijske mliječne kiseline na fermentaciju i aerobnu stabilnost kukuruzne silaže naknadne sjetve Kukuruz je bran u mliječnom stadiju. Upotrijebljeno je cjepivo 1174 (Pioneer®, SAD) kao homofermentacijsko cjepivo mliječne kiseline. Cjepivo je primijenjeno 6.00 log10 cfu/g razina silaže. Silaže bez aditiva poslužile su kao kontrolne. Nakon tretmana isjeckan kukuruz je siliran u laboratorijskom silosu tipa PVC. Izabrana su tri silosa za svaku skupina za kemijsku i mikrobiološku analizu 2., 4., 7., 14., 21., 28. i 56. dana nakon siliranja. Na kraju razdoblja siliranja sve su silaže podvrgnute 14 dana testiranju aerobne stabilnosti. Niti jedno cjepivo nije poboljšalo parametre fermentacije kukuruzne silaže. Na kraju siliranja cjepivo je povećalo laktobacile i smanjilo broj kvasaca i plijesni u silažama. Tretiranje cjepivom nije djelovalo na aerobnu stabilnost silaže

A comparative study on the abundance and elemental composition of POM in three interconnected basins: the Black, the Marmara and the Mediterranean Seas

The abundance and elemental composition of suspended particulate organic matter in the upper layers of the interconnected Mediterranean, Marmara and Black Seas having different ecosystems were determined in 1990-1998. The aim was principally to compare the C:N:P ratio of seston and understand factors controlling the seston composition in near- and off-shore waters of these seas. In the Marmara Sea, euphotic zone average particulate concentrations varied regionally and seasonally between 10-35 ìM for POC, 0.4-4.5 ìM for PON and 0.05-0.45 ìM for PP. These concentrations are mostly above the off-shore Black Sea values but much greater than those measured in the open waters of the north-eastern Mediterranean whose near-shore data are comparable with the seston content of the deep Black Sea. Comparison of C:N:P ratios of seston reveals that atmospheric and land-based phosphorus input influences the C:P and N:P ratios in the near-shore waters. Apparent nutrient deficiencies observed in the water column were not as remarkable in the elemental composition of seston. Unexpectedly, in the NE Mediterranean, N:P ratios from regression analyses of particulate data are very low (7-9) in the coastal region but slightly increase to levels of 10-15 in the open sea. In the Sea of Marmara, the N:P ratios (7-12) of seston are as low as in the Mediterranean, being consistent with the particulate ratios of the Black Sea inflow and NO3:PO4 ratios of the Marmara sub-halocline water. The Black Sea seston is relatively rich in carbonaceous compounds with N:P ratio ranging merely between 15-17 in the open sea but 9-27 in coastal waters where riverine discharges markedly influence the stoichiometry of seston

Synthesis of Large Area Graphene for High Performance in Flexible Optoelectronic Devices

This work demonstrates an attractive low-cost route to obtain large area and high-quality graphene films by using the ultra-smooth copper foils which are typically used as the negative electrodes in lithium-ion batteries. We first compared the electronic transport properties of our new graphene film with the one synthesized by using commonly used standard copper foils in chemical vapor deposition (CVD). We observed a stark improvement in the electrical performance of the transistors realized on our graphene films. To study the optical properties on large area, we transferred CVD based graphene to transparent flexible substrates using hot lamination method and performed large area optical scanning. We demonstrate the promise of our high quality graphene films for large areas with ∼400 cm 2 flexible optical modulators. We obtained a profound light modulation over a broad spectrum by using the fabricated large area transparent graphene supercapacitors and we compared the performance of our devices with the one based on graphene from standard copper. We propose that the copper foils used in the lithium-ion batteries could be used to obtain high-quality graphene at much lower-cost, with the improved performance of electrical transport and optical properties in the devices made from them

Karpal Tünel Sendromu Dekompresyon Cerrahisi Geçiren Hastaların Geç Dönem Memnuniyet Düzeylerini Değerlendirmede Elektromiyografi ve Hasta Değerlendirme Ölçümünün Geçerliliği

Objective: This study investigated whether electromyelography (EMG) evaluation is helpful in the late phase after surgical treatment of carpal tunnel syndrome (CTS). Methods: This retrospective study included 35 patients who underwent mini-open decompression therapy between 2008 and 2011 with CTS diagnosis. Patients were assessed electrophysiologically and clinically with Patient Evaluation Measurement (PEM) scoring and handgrip, palmar grip, lateral grip, and fingertip grip strength. Additionally, patients' clinical scores and strength values were compared with electrophysiologic values from preoperative and postoperative 4-year controls. Results: According to the Padua classification, EMG data were classified before and after surgery. One patient had extreme grade, four patients had severe grade, 26 patients had moderate grade, and four had a mild grade before surgery. At the postoperative 4th year EMG follow-up, six patients were classified as minimal and 29 as negative. According to the PEM scale, the mean score before surgery was 58.77±7.89, and in the controls at the 4th year after surgery, the mean score was 13.48±4.01. The strength of the operated hand was significantly weaker than that of the contralateral healthy hand before surgery. However, in the controls at the 4th year after surgery, the strength of the operated hand was significantly increased compared with the preoperative period, and there was no significant difference from the contralateral hand. Conclusion: Electrophysiological assessment (EMG) in the late phase after surgical treatment of CTS has positive parallels with clinical assessment and strength assessment. Therefore, we conclude that EMG helps follow late surgical outcomes. © Copyright 2022 by Medical Journal of Bakırköy published by Galenos Yayınev

The spatial range of peripheral collinear facilitation

Contrast detection thresholds for a central Gabor patch (target) can be modulated by the presence of co-oriented and collinear high contrast Gabors flankers. In foveal vision collinear facilitation can be observed for target-to-flankers relative distances beyond two times the wavelength (λ) of the Gabor's carrier, while for shorter relative distances (<2λ) there is suppression. These modulatory influences seem to disappear after 12λ. In this study, we measured contrast detection thresholds for different spatial frequencies (1, 4 and 6 cpd) and target-to-flankers relative distances ranging from 6 to 16λ, but with collinear configurations presented in near periphery at 4° of eccentricity. Results showed that in near periphery collinear facilitation extends beyond 12λ for the higher spatial frequencies tested (4 and 6 cpd), while it decays already at 10λ for the lowest spatial frequency used (i.e., 1 cpd). In addition, we found that increasing the spatial frequency the peak of collinear facilitation shifts towards larger target-to-flankers relative distances (expressed as multiples of the stimulus wavelength), an effect never reported neither for near peripheral nor for central vision. The results suggest that the peak and the spatial extent of collinear facilitation in near periphery depend on the spatial frequency of the stimuli used