Secondary Hole Research Articles

Transfer and Distribution of Gunshot Residue through Glass Windows.

Research into the deposition patterns of primer gunshot residue (GSR) beyond a primary target was previously nonexistent. This study aimed to determine the deposition patterns of GSR once a bullet passed through an initial target and continued on its path into additional targets. Multiple repetitions were performed to assess the GSR deposition patterns after a bullet was shot through a closed window into either a dummy or a wall within an enclosed room. Samples were taken from both the primary and secondary target holes as well as from nontarget areas. Significant amounts of GSR were found on all samples. The results show that GSR continues to be deposited along the path of the bullet after passing through a primary glass target. These findings reiterate the lack of probative value in collecting GSR samples from gunshot victims even if they are in an enclosed area separate from the shooter.

Dynamical Friction and the Evolution of Supermassive Black Hole Binaries: The Final Hundred-parsec Problem

Abstract The supermassive black holes originally in the nuclei of two merging galaxies will form a binary in the remnant core. The early evolution of the massive binary is driven by dynamical friction before the binary becomes “hard” and eventually reaches coalescence through gravitational-wave emission. We consider the dynamical friction evolution of massive binaries consisting of a secondary hole orbiting inside a stellar cusp dominated by a more massive central black hole. In our treatment, we include the frictional force from stars moving faster than the inspiralling object, which is neglected in the standard Chandrasekhar treatment. We show that the binary eccentricity increases if the stellar cusp density profile rises less steeply than . In cusps shallower than , the frictional timescale can become very long due to the deficit of stars moving slower than the massive body. Although including fast stars increases the decay rate, low mass-ratio binaries ( ) in sufficiently massive galaxies have decay timescales longer than one Hubble time. During such minor mergers, the secondary hole stalls on an eccentric orbit at a distance of order one-tenth the influence radius of the primary hole (i.e., for massive ellipticals). We calculate the expected number of stalled satellites as a function of the host galaxy mass and show that the brightest cluster galaxies should have of such satellites orbiting within their cores. Our results could provide an explanation for a number of observations, which include multiple nuclei in core ellipticals, off-center AGNs, and eccentric nuclear disks.

Photoiduced Electron Transfer Across Phthalocyanine Layers on ZnO Semiconductor

Photo-reactions in hybrid organic-semiconductor structures have significant importance for developing applications with probably most visible being solar cells [1]. The progress with the applications depends crucially on our knowledge and ability to control electronic interactions between the semiconductor and organic molecules attached to it. The properties of the latter, the organic dye layer on semiconductor surface, are heavily affected by inter-molecular interactions in the layer, which complicate engineering of well functioning devices. One promising class of organic dyes in photonic applications is phthalocyanine (Pc). Pcs are generally photo and chemically stable compounds. Pcs have extended π-system resulting in intense absorption bands in the red part of the spectrum, which is beneficial for solar cell applications. There was a number of attempts to use Pcs in dye sensitized solar cell (DSSC), but the obtained efficiencies were essentially lower than that for the best dyes sensitisers [1]. The most probable reason for this is strong aggregation tendency of Pcs which are essentially flat molecules with very well known tendency of stacking due to π-interaction between the macrocycles. The aggregation enables fast deactivation channels for the excited state [2], which competes with the electron injection to semiconductor in DSSC, or charge separation between two organic counterparts in bulk heterojunctions. To reduce the aggregation effect, synthetic efforts were undertaken to decorate Pcs with bulky groups preventing aggregation but having no or little effect on Pc electronic properties. This presentation focuses on photo-physics of monolayers of a series of aggregation protected Pcs on surface of ZnO nanorods [3]. The main tool for the study was femtosecond transient absorption spectroscopy. It revealed dynamics of electron injection form photoexcited Pc to ZnO substrate. The average time constant of the electron injection was found to be in the range 1-5 ps, but the dependence of the time constant on the bulky substituents and type of linker connecting Pc to ZnO surface was not apparently obvious. A reasonable explanation of the results was found after molecular modelling of Pcs on the ZnO surface. The modelling suggests that Pc has tendency to tilt toward the surface and the final configuration and the distance from Pc to ZnO surface is determined by both the linker and peripheral groups. An advantage of using array of vertically aligned ZnO nanorods is that it has essentially higher specific surface area compared to that of a flat surface, but is relatively ease to access. The outer side of Pcs layer was covered by a layer of secondary electron donor or hole transporting material, Spiro-OMeTAD (Spiro), by simple spin coating [4]. The coating changes the order of charge transfer reactions drastically. The charge separation at the Pc-Spiro interface becomes dominating channel of the Pc excited state relaxation, resulting in Pc anion - Spiro cation pair. The Pc anion injects the electron to ZnO but with average time constant much longer (roughly 100 ps) than the electron injection form the Pc singlet excited state in the absence of Spiro.

Design of a Top-Lit Up-Draft Micro-gasifier Biomass Cookstove by Thermodynamic Analysis and Fluent Modeling

In this work the complete thermo-mechanical design of a biomass top-lit up-draft (TLUD) cookstove is presented. A design methodology which is based on mass and energy balances, geometry relations among the main dimensions of the cookstove, and fluent modeling is proposed. Three models were designed, sized, and simulated through computational fluid dynamics (CFD) conducted in ANSYS Fluent 15.0.7. These designs allowed analyzing the effect of cookstove design, primary and secondary air inlets (diameter and air supply setup) required in the gasification and combustion processes, respectively. Simulations indicated that compressed air is not a suitable way to supply the air flow for gasification and combustion stages, due to the poor velocity distribution across the grate and secondary holes. Therefore, the final stove design will operate with axial fans to favor a good mixture between biomass and the air in the gasification stage, and between producer gas and the air in the combustion zone. Operation with axial fans, in the final cookstove design, allowed obtaining a low standard deviation of air velocity through the grate holes and through secondary air ring holes (±0.13 m/s, and ±0.45 m/s, respectively), which entails a better cookstove performance. This air supply system, also presented combustion air velocities through the secondary ring holes according to the ones reported in the literature (3.02 m/s), which is important for the suitable air and producer gas mixing.

Designing a Cooker to Utilise the Natural Waste Rice Husk as a Cooking Gas

Environmental pollution is big issue in the world, which is from the natural by-products. Some of these byproducts can be transformed into alternative energy source. Rice husk is the one of the natural by-product which is freely available in Sri Lanka that can be used to produce gas for cooking. To utilise the natural by-products a cooker was designed and the performance of the cooker was evaluated. The cooker consists a gasifier, char chamber, air blowing system and a burner. The rice husk was feed into the gasifier through the top of the cooker and lighted. The gas was produced through air force blown into the reactor through the fan to the husk and the atmospheric air from the secondary holes around the burner for proper oxygenation. The performance test was done by boiling 1 litres of water within 7 minutes and the result revealed that the efficiency of the cooker is 27.17%. The efficiency of the cooker could be increased by continuous flow of rice husk feeding. The end product rice husk ash could be utilising as a raw material in cement, bricks and fertilizer production.

Secondary Macular Hole Formation after Pars Plana Vitrectomy for Vitreous Hemorrhage

To describe a case of a secondary macular hole (MH) after pars plana vitrectomy for vitreous hemorrhage.

Improving film cooling from compound angle holes by adding secondary holes branched out from the main holes

A numerical simulation is used to investigate the effect of adding secondary hole branched out from a compound angle injection hole. The use of secondary holes with compound angle film cooling is considered as a novel concept of compound angle film cooling. The used orientation angle is 30°. The diameter of the secondary hole is half of the main diameter (compound angle injection hole diameter). The studied cases are considered at blowing ratios of 0.5, 0.75, 1.0, 1.5, 2.0, and 2.5. The study was carried out using the realizable k-e model. The presence of the secondary hole improves the film cooling at all studied blowing ratios except at M = 0.5 due to the weakness of the coolant flow through the main hole. The flow through the secondary hole tries to damp the vortex coming out from the main hole. The optimum blowing ratio is at M = 0.75–1.0. The enhancement in the overall film cooling effectiveness at M = 1 is 0.12 as compared to the compound angle injection hole case by about 83%.

Hydrophilic and size-controlled graphene nanopores for protein detection

This paper describes a general approach for transferring clean single-layer graphene onto silicon nitride nanopore devices and the use of the electron beam of a transmission electron microscope (TEM) to drill size-controlled nanopores in freely suspended graphene. Besides nanopore drilling, we also used the TEM to heal and completely close the unwanted secondary holes formed by electron beam damage during the drilling process. We demonstrate electron beam assisted shrinking of irregularly shaped 40–60 nm pores down to 2 nm, exhibiting an exquisite control of graphene nanopore diameter. Our fabrication workflow also rendered graphene nanopores hydrophilic, allowing easy wetting and use of the pores for studying protein translocation and protein–protein interaction with a high signal to noise ratio.

Experimental investigation of the influence of freestream turbulence on an anti-vortex film cooling hole

Film cooling is used in gas turbines to thermally protect combustor and turbine hot section components by creating a layer of relatively cooler air to insulate the components from the hot freestream gases. This relatively cooler air is taken from upstream in the compressor section at a loss to the engine efficiency and therefore must be used as effectively as possible. A novel anti-vortex hole (AVH) geometry has been investigated experimentally through a transient infrared thermography technique to study the film cooling effectiveness and heat transfer coefficient by varying blowing ratio and freestream turbulence intensity. The AVH geometry is designed with two secondary holes stemming from a main cooling hole that attempts to diffuse the coolant jet and mitigate the vorticity produced by conventional straight holes. The AVH geometry data collected showed improved cooling performance at low freestream turbulence intensities compared to conventional straight holes. Three turbulence intensities of 1, 7.5, and 11.7% were investigated for the AVH geometry at blowing ratios of 0.5, 1.0, 1.5, and 2.0 for a total of twelve different conditions. Results showed that higher freestream turbulence conditions were beneficial to the performance of the AVH. Increasing the blowing ratio at all turbulence levels also improved film cooling effectiveness, both span-averaged and on the centerline. The highest performing case was at a turbulence intensity of 7.5% and a blowing ratio of 2.0. The 11.7% cases outperformed the 1% cases, but it appears that at the 11.7% cases the higher freestream turbulence reduces the performance of the secondary holes compared to the 7.5% case. Increasing the blowing ratio and turbulence intensity will result in a higher heat transfer coefficient, which must be taken into account for future designs and overall reduction of heat load.

THE ASSOCIATION OF EPIRETINAL MEMBRANE WITH MACULAR HOLE FORMATION AFTER RHEGMATOGENOUS RETINAL DETACHMENT REPAIR.

To describe the clinical and optical coherence tomography findings associated with the development of full-thickness macular holes after rhegmatogenous retinal detachment (RRD) repair. Retrospective, interventional case series. All patients who developed full-thickness macular holes after successful RRD repair from 3 clinical practices were reviewed. All cases of combined/simultaneous full-thickness macular hole and RRD were excluded. The main outcome measure was the presence of an epiretinal membrane at time of diagnosis of macular hole. Twenty-five full-thickness macular holes were diagnosed after successful retinal detachment repair. Surgical approach to RRD repair included pneumatic retinopexy (6, 24%), scleral buckle alone (5, 20%), pars plana vitrectomy only (8, 32%), and combined scleral buckle and pars plana vitrectomy (6, 24%). The preceding RRD involved the macula in 19 patients (76%) before the formation of the macular hole. The median time to full-thickness macular hole diagnosis after RRD repair was 63 days (range, 4-4,080 days). An epiretinal membrane was present in all 25 (100%) macular holes. Two macular holes (8%) spontaneously closed, whereas the other 23 (92%) were successfully closed with a single surgical procedure. Mean visual acuity improved by approximately 5 lines to 20/72 (range, 20/20 to counting fingers at 1 foot) from 20/240 (range, 20/30 to hand motions) after macular hole repair (P < 0.0001). Full-thickness macular hole formation can occur after all types of RRD repair and is associated with an epiretinal membrane. The epiretinal membrane may play a role in the pathogenesis of secondary macular hole formation after RRD repair.

Optimal cooperative beamforming design in cognitive radio networks with multiple secondary user links

SummaryIn this paper, a novel beamforming method is proposed for a more realistic cognitive radio system with several secondary transmitters and receivers, a number of relays, and 1 primary transmitter and receiver. When the primary user link is idle, all secondary transmitters access temporal spectrum holes to simultaneously broadcast their information to the relays each associated with an infinite buffer. In the next stage, the relays transmit the information to the secondary receivers using a cooperative beamforming method no matter whether primary user link is silent or not. The proposed method of designing the beamforming vector enables the system to maximize the power received by the secondary users while maintaining the interference plus noise power at the primary user receiver below a predefined threshold. Results of simulations confirm validity of the method and improved performance compared to the zero‐forcing beamforming. The impact of channel quality between nodes on the performance of the system is also investigated.

Innovative Tool Improves Hole-Cleaning Efficiency in Extended-Reach Wells

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 175165, “Use of an Innovative Tool To Improve Hole-Cleaning Efficiency in Extended-Reach Wells in Saudi Arabia,” by Mike Okot, Marlio Campos, German Muñoz, and Alawi G. Alalsayednassir, Saudi Aramco; Matt Weber, Frank’s International; and Zahid Muneer, SPE, Schlumberger, prepared for the 2015 SPE Kuwait Oil and Gas Show and Conference, Mishref, Kuwait, 11–14 October. The paper has not been peer reviewed. Saudi Aramco operates a large offshore oilfield development that has driven achievements in multilateral and extended-reach directional wells. One challenge the operator faces is to maintain proper hole cleaning in extended 8½-in. tangent sections at 85–87° inclinations, which are drilled in excess of 10,000 ft. In an effort to drill efficiently, a new technology to increase cuttings removal was trial tested on Well A1 from an onshore location of the field. Introduction Historically, drilling very long tangent sections required the use of several tandem sweep pills, wiper trips, and reaming and back reaming to maintain hole quality and remove cuttings from the wellbore efficiently. Poor hole cleaning can lead to tight intervals, increased torque and drag, and, eventually, stuck pipe. Extended-reach Well A1 was drilled to a measured depth (MD) of 30,480 ft [8,650-ft true vertical depth (TVD)] into a stratigraphic environment composed of limestone, shale, and siltstone. The objective of the trial test for the tool was to improve the drilling efficiency. To obtain the best possible hole cleaning, a simulation was performed by placing the new tools every three stands along the tangent section in the 8½-in.-hole section. The goals of the trial test were To enhance hole cleaning by removal of cuttings To reduce the frequency and number of tandem sweep pills To reduce the frequency and number of wiper trips To reduce torque and drag levels and make them comparable with those of offset wells To reduce drilling cost Well A1 resumed drilling from a preset 9?-in.-casing point in December 2013 in the Manifa field. The well was drilled from surface to 30,480-ft MD and into a stratigraphic environment composed of limestone, sandstone, and siltstone. The objective was to hold vertical from surface to 1,535 ft, build up to 85° from 1,535 to 11,659 ft, and hold an 85–90° inclination to total depth. The challenges were to clean hole while drilling the long 8½-in. tangent section from 11,659 to 24,160 ft. To address these challenges, the tool company recommended the use of 5-in. cuttings-bed- impeller (CBI) tools at a frequency of one tool per three stands on the 5-in. drillpipe. The 8½-in. tangent section was drilled smoothly without any hole-cleaning issues (no tight hole or stuck pipe). The primary hole cleaning was achieved during drilling, and no secondary hole cleaning was required. A service company installed a cuttings-flowmeter system at the shakers to evaluate hole-cleaning efficiency and performance of the hole-cleaning tools.

Effect of secondary orientation on room temperature tensile behaviors of Ni-base single crystal superalloys

The influence of secondary orientation and holes on the localization and the evolution of plasticity during room temperature tensile tests of thin wall specimens of a Ni-base single crystal superalloy were investigated. An ARAMIS system based on the digital image correlation technique was employed to in-situ observe the strain distribution on the sample surfaces, and an in-situ scanning electron microscopy was used to in-situ observe the slip traces development during tensile tests. For the smooth specimens, the tensile strength of<110>specimen is slightly higher than that of<100>specimen (<110>and<100>are the secondary orientations of the specimens). However, in the case of specimens with a hole in gauge section, detailed analysis indicates that 3-D tensile stress in the vicinity of the hole results in more slip systems initiated in<100>specimens, which may lead to stronger strain hardening. As a result, higher strength is obtained in<100>specimens with a hole.

Assessing nodes importance in complex networks using structural holes

Accurate measurement of important nodes in complex networks has great practical and theoretical significance. Mining important nodes should not only consider the core nodes, but also take into account the locations of the nodes in the network. Despite much research on assessing important nodes, the importance of nodes in the structural holes is still easily ignored. Therefore, a local measuring method is proposed, which evaluates the nodes importance by the total constraints caused by the lack of primary structural holes and secondary structural holes around the nodes. This method simultaneously considers both the centrality and the bridging property of the nodes' first-order and second-order neighbours. Further to prove the accuracy of the method TCM, we carry out deliberate attack simulations through selective deletion in a certain proportion of network nodes. Then, we calculate the decreased ratio of network efficiency in the before-and-after attacks. Experiment results show that the average effect of the TCM in four real networks are improved by 50.64% and 14.92% compared to the clustering coefficient index and the k-shell decomposition method, respectively. Obviously, the TCM is more accurate to mine important nodes than other two methods, and it is suitable for quantitative analysis in large-scale networks.

Unidirectionally progressive resection of lower left lung carcinoma under video-associated thoracoscopy.

General anesthesia is adopted through double-lumen endotracheal intubation, one-lung ventilation on the contralateral, and intravenous injection. The patient took a 90 degree decubitus on his contralateral side. The operative incisions: the observation port was made in the mid-axillary line of the 7(th) intercostal section, a second horizontal incision of 4 cm as the main operation port at the 4(th) intercostal space between the anterior axillary line and the midclavicular line, and a 3(rd) incision of 1.5 cm as the secondary operation hole at the 9(th) intercostal space between the axillary line and the bottom scapular line. The surgeons were on the ventral side of the patient, and operated with endoscope apparatus in front of the monitor screen.

Time-resolved electron kinetics in swift heavy ion irradiated solids

The event-by-event Monte Carlo model, TREKIS, was developed to describe the excitation of the electron subsystems of various solids by a penetrating swift heavy ion (SHI), the spatial spreading of generated fast electrons, and secondary electron and hole cascades. Complex dielectric function formalism is used to obtain relevant cross sections. This allows the recognition of fundamental effects resulting from the collective response of the electron subsystem of a target for excitation that is not possible within the binary collision approximation of these cross sections, e.g. the differences in the electronic stopping of an ion and in the electron mean free paths for different structures (phases) of a material. A systematic study performed with this model for different materials (insulators, semiconductors and metals) revealed effects which may be important for an ion track: e.g. the appearance of a second front of excess electronic energy propagation outwards from the track core following the primary front of spreading of generated electrons. We also analyze how the initial ballistic spatial spreading of fast electrons generated in a track turns to the diffusion ~10 fs after ion passage. Detailed time-resolved simulations of electronic subsystem kinetics helped in understanding the reasons behind enhanced silicon resistance to SHI irradiation in contrast to easily produced damage in this material by femtosecond laser pulses. We demonstrate that the fast spreading of excited electrons from the track core on a sub-100 fs timescale prevents the Si lattice from nonthermal melting in a relaxing SHI track.

Modulating Electron Transfer Dynamics Via Graphene Interactions in Donor-Acceptor Systems

Sequential electron transfer or electron transfer/hole transfer between energetically well-positioned entities of photosynthetic reaction center donor-acceptor models is one of the commonly employed mechanisms to generate long-lived charge separated states. Wealth of information, applicable towards light energy harvesting and building optoelectronic devices, has been acquired from such studies. In the present study, we report charge stabilization in multi-modular donor-acceptor pentads comprised of phenothiazine, subphthalocyanine and fullerene as molecular components.1 In these pentads, the subphthalocyanine and fullerene serve as primary electron donor and acceptor, while the phenothiazine entities act as secondary hole transferring agents. The newly synthesized compounds were characterized by optical absorption and emission, computational and electrochemical methods. The redox potentials measured using differential pulse voltammetry were used to estimate free-energy changes for charge separation, hole migration, and charge recombination processes. Using femto- and nanosecond transient absorption techniques, evidence for charge separation, and kinetics of charge separation and recombination were obtained in polar benzonitrile and nonpolar toluene solvents. The kinetic data obtained by analyzing the time profiles of the radical ions revealed occurrence of ultrafast charge separation and relatively slow charge recombination processes as a result of electron transfer-hole shift mechanism in these pentads. The measured rate of charge separation, k CS were in the range of 1.2 - 4.4 x 1010 s-1 while the rate of charge recombination, k CR were in the range of 1.3 - 5.4 x 106 s-1, depending upon the design and solvent polarity, revealing charge stabilization in the pentads. Further, by the interaction of phenothiazine entities of the triad with graphene, modulation of electron transfer events has been accomplished. Details of these investigations will be presented. 1KC, C. B.; Lim, G. N.; Zandler, M. E.; D’Souza, F., Org. Letts. 2013, 15, 4612-4615.

Lake Cheko and the 1908 Tunguska Event

The so-called Tunguska Event (TE), of June 30 1908, is one of those phenomena that have generated a great and durable interest into generations of earth and planetary scientists and a worldwide audience. This is due to several causes, including the remoteness of the site where it occurred and the global scale of its effects. Thousands of kilometers from the epicentre, over Russia and the Northern Europe, the TE was perceived as a series of unusual phenomena, such as seismic and pressure waves and a bright luminescence in the night skies. Only several years later, in 1927, Leonid Kulik reached the explosion site, a remote region of Central Siberia close to the river Podkamennaya Tunguska, which gave later the name to the event. Kulik identified the epicentre of the explosion in a heavily forested area from the radial distribution of flattened trees. He also found many trees that were left standing directly below the explosion, although deprived of their branches and partially burned. Kulik reached the conclusion that he had discovered the remains of a large impact crater hidden by a swamp and a number of secondary bowl-shaped holes of different sizes covered by peat bogs. This pattern could have been caused by an asteroid that fell in a swarm of separate fragments. Other authors questioned this interpretation, suggesting that the observed circular features were not necessarily related to extraterrestrial impacts, but probably to seasonal thawing and freezing of the ground. Two observations favoured this second interpretation: circular features of similar size are common at these latitude; these depressions were found in low-lying areas, but not on the slopes of the hills, or on any of the reliefs occupying a considerable part of the epicentre region. Moreover, all attempts at finding macro-remnants of the cosmic body by digging these circular depressions were unsuccessful; therefore, the hypothesis of an impact with the ground was abandoned. Subsequent expeditions have been devoted mainly to the study of the tree patterns in the devastated taiga and to the search for micro particles of the cosmic body, under the assumption that it exploded in the atmosphere. After more than a century, the TE is far from being completely understood, although it has been the object of several studies. The most probable hypothesis is that it was caused by the impact with the Earth of a cosmic body, a comet or an asteroid, which exploded about 5–10 km above the ground, releasing in the atmosphere 10–15 Mtons of energy. However, fragments of the impacting Tunguska Cosmic Body (TCB) have never been found, and its nature is still a matter of debate. Geophysical and geological data collected from a small lake about 8 km NNW of the inferred TE epicentre suggest that it is probably a crater left by the impact of a large TCB fragment. Evidence supporting this interpretation includes its funnel-like bottom morphology, revealed by high-resolution bathymetry, and the structure and composition of sedimentary deposits below the lake floor, studied through acoustic imagery and direct sampling. Seismic reflection profiles collected from the lake show a density/P-wave velocity anomaly located about 10 m below its bottom, probably the effect of a buried object, which could have created the lake’s depression, or a density anomaly caused by overpressure due to the impact. A magnetic anomaly also marks the presence of such feature. If Lake Cheko, as much evidence seems to suggest, was formed as a consequence of an extraterrestrial impact, it opens the problem of recognizing impact-related features on a composite target such as the Earth surface, very different from the Moon and the other terrestrial planets of the Solar System, where the morphology of “typical” impact features has been mostly studied.

A Novel Standardized Reproducible Method to Calculate the Area of Internal Limiting Membrane Peeled Peroperatively in Macular Hole Surgery by Using a Video Overlay - Boral’s Ring

The challenges in macular hole surgery1-7 include the following:1. Till date no study described the standardized logical reproducible method of calculating area of ILM peeled(AIP) in macular hole surgery and 2. The area of Internal Limiting Membrane (ILM) that has to be peeled to ensure post-operative macular hole closure without any foveal neurosensory retinal defect is not well defined. Our aim was to highlight the way to calculate the Area of Internal Limiting Membrane Peeled (AIP) and its relation with hole closure pattern on OCT in idiopathic FTMH cases. We conducted a prospective single blind study taking 105 eyes/105 patients with symptomatic Idiopathic FTMH< 6months duration. We included idiopathic full thickness macular holes, excluding cases of secondary macular holes, old macular holes with symptoms more than six months duration and eyes with small & large optic discs. All cases were operated by four VR surgeons in our hospitals, where triamcinolone assisted vitrectomy, PVD induction, BBG dye assisted ILM peeling done followed by fluid air exchange and injection of C3F8 gas in non expansile conc . All surgeries were video recorded. Three parameters were evaluated – pre Techniques

Improving the sensitivity of a near-infrared nanocomposite photodetector by enhancing trap induced hole injection

We report the enhancement of the photoconductive gain of nanocomposite near-infrared photodetectors by a zinc oxide nanoparticles (ZnO NPs) rich surface at the nanocomposite/cathode interface. An argon plasma etching process was used to remove polymer at the surface of nanocomposite films, which resulted in a ZnO NPs rich surface. The other way is to spin-coat a thin layer of ZnO NPs onto the nanocomposite layer. The ZnO NPs rich surface, which acts as electron traps to induce secondary hole injection under reverse bias, increased hole injection, and thus the external quantum efficiency by 2–3 times. The darkcurrent declined one order of magnitude simultaneously as a result of etching the top nanocomposite layer. The specific detectivity at 800 nm was increased by 7.4 times to 1.11 × 1010 Jones due to the simultaneously suppressed noise and enhanced gain.