Medium Thicknesses Research Articles

Central and peripheral scleral lens-induced corneal oedema.

To quantify the magnitude of central and peripheral scleral lens-induced corneal oedema for a range of fluid reservoir thicknesses, and to compare these experimental results with theoretical models of corneal oedema both with and without limbal metabolic support (i.e., the lateral transport of metabolites and the influence of the limbal vasculature). Ten young healthy participants wore scleral lenses (KATT™, Capricornia Contact Lenses) fitted with low (mean 141 μm), medium (482 μm) and high (718 μm) central fluid reservoir thickness values across three separate study visits. The scleral lens thickness, fluid reservoir thickness and stromal corneal oedema were measured using optical coherence tomography. Oedema was quantified across the central (0-2.5 mm from the corneal apex) and peripheral (1.25-3 mm from the scleral spur) cornea. Experimental data were compared with published theoretical models of central to peripheral corneal oedema. Stromal oedema varied with fluid reservoir thickness (p < 0.001) for both central and peripheral regions. The mean (standard deviation) stromal oedema was greater for the medium (2.08 (1.21)%) and high (2.22 (1.31)%) fluid reservoir thickness conditions compared to the low condition (1.00 (1.01)%) (p ≤ 0.01). Stromal oedema gradually increased from the corneal centre to the periphery by ~0.3% on average (relative increase of 18%), but the change did not reach statistical significance. This trend of increasing, rather than decreasing, oedema towards the limbus is consistent with theoretical modelling of peripheral oedema without metabolic support from the limbus. The central and peripheral cornea displayed a similar magnitude of oedema, with increasing levels observed for medium and high fluid reservoir thicknesses. The gradual increase in oedema towards the limbus is consistent with a 'without limbal metabolic support' theoretical model.

Predicting entropy generation of a hybrid nanofluid in microchannel heat sink with porous fins integrated with high concentration photovoltaic module using artificial neural networks

This paper evaluates the characteristic of second law of thermodynamic, including Bejan number and entropy generation for hybrid nanofluid containing graphene-silver nanofluid through a MCHS whit porous fins. Finite-volume technique is utilized to solve the governing equations. To simulate the problem, different porous medium thicknesses, nanoparticle concentrations, and inlet mass flow rates are used while the heat flux remains constant. The minimum values of the frictional and thermal entropy generation are 5 × 10−4 and 6.25 × 10−2, while the maximum values are 3.2 × 10−4 and 9.75 × 10−2. With increasing nanoparticle concentration up to 0.06% wt at constant porous thickness tp=200 µm, frictional entropy generation rises up by 3 × 10−5 and heat transfer rate go up while, thermal entropy generation decreases by 1.5 × 10−2. In addition, by doubling the input mass flow rate and reaching 0.02% at constant nanoparticle concentration (0.06%), thermal entropy generation decreases by 2 × 10−2 while the frictional entropy generation increases by 2.4 × 10−4. The minimum magnitude of Bejan number is 0.994. This show that the irreversibility is derived significantly from thermal entropy generation rate. Finally, an artificial neural network is employed to obtain a model for entropy generation.

Experimental Study on the Dynamic Mechanical Properties of a Jointed Rock Mass under Impact Loading

The propagation law of blast stress waves in jointed rock masses is closely related to the characteristics of the joint filling medium. The water content and thickness of the filling medium affect the propagation characteristics of the blast stress wave in the joint surface. Based on similarity theory, mortar-red clay-mortar composite specimens with different moisture contents (36%, 39%, 42%, and 45%) and medium thicknesses (3 mm, 6 mm, and 9 mm) were prepared with red clay as the filling medium. The dynamic uniaxial compression test of the specimen under different strain rates was carried out by using a variable cross-section split Hopkinson compression bar with a diameter of 50 mm. The effects of strain rate, moisture content, and medium thickness on the stress wave propagation characteristics, dynamic stress-strain curve, peak stress, crushing energy consumption density, and crushing characteristics of mortar-red clay-mortar composite specimens were analyzed. The results show that the blocking effect of joints on stress waves increases significantly with increasing filling medium thickness and water content. With increasing strain rate, the peak stress and energy of the composite specimen increase and there is an obvious strain rate effect. With the increase in the thickness and moisture content of the filling medium, the peak stress, dynamic elastic modulus, energy consumption density per unit volume, and crushing degree of the specimen gradually decrease and the nonlinear deformation is more obvious. There is a good linear relationship between the peak stress and the thickness and moisture content of the filling medium. The existence of joints greatly weakens the damage effect of stress waves on the specimens behind the joints, and with the increase in the thickness and water content of the filling medium, the degree of damage to the specimens behind the joint surface decreases under the same impact pressure and the weakening effect becomes increasingly significant.

Forward projection multilayer refraction model for underwater camera calibration

Unlike imaging in air, underwater imaging is affected by two distinct properties of water: the absorption and scattering effect of water and the refraction effect of water, resulting in the conventional pinhole model no longer being suitable for underwater imaging. Therefore, without prior calibration in air to calculate the camera intrinsic parameters and distortions for subsequent underwater calibration, an underwater multilayer refraction model based on forward projection method is represented. Along the direction of light propagation, the multilayer refraction model presents a unified scale factor instead of focal length during the perspective projection transformation from the camera coordinate system to the image coordinate system. Simulations regarding the analysis of different medium thicknesses, different medium refractive indices, and different point pixels are performed to explore the influence of the above three parameters on the refraction model. Through the underwater parameter identification and verification, the proposed multilayer refraction model has high measurement accuracy, excellent solution efficiency, stable identification results, more identification parameters, and wide application fields, which are suitable for both single-time refraction and double-time refraction.

Optimizing diet thickness and egg density for economic mass rearing of Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae): A laboratory host for biological control agents

BackgroundMediterranean flour moth [Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae)] (MFM hereafter) is a significant pest of stored products, particularly flour and causes significant economic damages. However, its eggs are important laboratory host for mass rearing of biological control agents of important agricultural pests. However, diet thickness and eggs’ density to be used in a specific area for economic mass rearing are not fully understood. MethodsThis study optimized the diet thickness and eggs’ density to be used in a specified area for harvesting higher number of MFM eggs with low cost. The MFM was reared under dark environment, i.e., 25 ± 1 °C temperature and 60–70% relative humidity in 32×26×6 cm plastic tubs. The diet consisted of wheat flour and wheat bran in 2:1 ratio by weight, respectively. Three diet thicknesses [i.e., 0.5 cm (thin), 1.5 cm (medium) and 2.5 cm (thick)] and three egg densities [i.e., 25 mg (low), 50 mg (medium) and 75 mg (high)] were tested to determine the most economic and productive combination. ResultsLife history traits, i.e., moths’ production, moths’ ratio and egg production were significantly altered by individual an interactive effect of diet thickness and egg density. The highest number of moths was obtained for medium diet thickness and high egg density. Medium diet thickness with low egg density resulted in the lowest number of moths. The highest number of eggs were produced by thin and medium diets and high egg density combinations, and these combinations proved the most economic for mass production of 100 g eggs. ConclusionThe results of the current study indicated that combination of medium and thin diet thicknesses with high egg density are the most economic for mass production of MFM. Interestingly, the study revealed that terminating moths’ collection at 2nd week after first moth emergence and egg collection at 4 days after the moths are placed in egg laying containers is the most suitable time for the economic mass rearing of MFM. However, egg densities >75 mg need further testing on thin and medium diet thicknesses to explore whether they are more economic than recommended densities in this study.

Development and research of new technologies for precision plasma cutting of metals

Plasma torches of Russian origin concede to import metal-cutting plasma facilities by several parameters, in particular energy efficiency, quality of cut, degree of automation. To increase efficiency and safety of domestic electro-plasma technologies itь is necessary to perfect methods of analysis of known design solutions to provide new developments. The results of the plasma torch­es design widely used in metallurgical and machine-building technologies for air-plasma cutting of metals presented. It was noted that productivity, cutting quality and reliability of plasma equipment should be chosen as the main criteria of efficiency for plasma cutting technology. It was shown that special attention should be paid to improving the gas-vortex stabilizing method for the plasma forming gas, which ensures the efficiency of both the plasma torch and the plasma cutting process as a whole. Results of studies of a complex system for arranging the flow of plasma-forming gas through the channels of the gas-air path in the plasma torch and the subsequent creation of new systems for stabilizing the arc discharge of metal cutting DC plasma torches with high technological capabilities presented. The study was carried out by the methods of numerical simulation of gas-dynamic and thermo-physical pro­cesses for various designs of plasma torches. Optimized designs of plasma torches with various variants of gas-vortex stabilization systems were elaborated. A series of elaborated torches, which includes a single-stream plasma torches ПМВР-5 for precision cutting of medium thickness metals, as well as two-stream plasma torches ПМВР-9 for cutting metals of small and medium thicknesses presented. The last plasma torches use the technology of narrow-jet or compressed plasma and have no domestic analogues. A meth­odology of metal-cutting plasma torches designing by gas-dynamic, thermo-physical and acoustic criteria was elaborated. The results of experimental studies showed that the use of new ПМВР-5 plasma torches allows to obtain precision cuts corresponding to the 1st and 2nd quality classes according to GOST 14792-80 on steels of the 09Г2С type of medium thickness. It was also shown that the use of new plasma torches makes it possible to perform precision finishing plasma cutting on low-carbon steels of medium thickness (without additional mechanical processing of the cutting edge) in the production technologies of welded joints.

Methods for flexibility determination of bolted joints: empirical formula review

In this work, a comparative analysis of existing methods for determining the compliance of mechanical joints such as ‘composite-composite’ and ‘composite-metal’ is performed. Polymer composite materials are widely used in modern aircraft industry. As a result, it is necessary to take into account the characteristics of joints of composite aggregates with composite and metallic ones. Considering the compliance of connections in the global finite element models of structural units of aircraft allows increasing the accuracy of calculations. The use of empirical formulae can significantly reduce time and labour costs in calculating the compliance of bolted connections for use in global finite element models. In this paper we review and analyse the existing empirical dependencies. Calculation of rigidity and compliance of single-shear ‘composite-composite’ and ‘composite-metal’ joints by finite element method for small, medium and large membrane thicknesses is carried out, and the results are compared with the calculations using empirical formulae. As a result of the analysis for medium and small thicknesses it is proposed to determine the value of bolted joint flexibility by the empirical formula Boeing 1, and for large thicknesses of connecting membranes it is proposed to use empirical formula Huth.

Determination of Some Structural Features of the Nest Paper Materials of Vespa crabro germana Christ, 1791 (Hymenoptera: Vespidae) in Turkey

The aim of this study was to identify the nest materials, some physical characteristics and the essential composition of the nest of Vespa crabro germanaChrist, 1791. Nest surfaces were observed with a stereomicroscope and a scanning electron microscope. In the inner surface of the V. c. germana nest, the medium thicknesses of the fibers in the envelope and comb varied between 5.30 and 11.90 µm with an average of 9.07 µm. In the outer surface of the nest, the medium thicknesses of the fibers in the envelope and comb were between 4.46 and 11.40 µm with an average of 7.68 µm. The nitrogen and protein concentration of the nest was 0.22 and 1.40%, respectively. The percentages of the fibers, saliva, oil and the water absorption capacity were calculated as 70-75, 25-30, 16-20 and 120-150, respectively. The amount of the elements nickel and copper in the nest was found to be 0.6 and 1.2 ppm, respectively. The major components of the nest were plant fibers, saliva and oil. Consequently, we have found that the ratios and the amounts of physical characteristics, the element composition and the fibers in the envelope and comb of the nest changed with environmental conditions.

Experimental investigation on a novel arrangement of wet medium for evaporative cooling of air

A low-speed wind tunnel was designed to experimentally study the cooling performance of a novel arrangement of wet medium for evaporative cooling of air. In the wet medium arrangement (CELdek7060), a 300 mm cooling section was formed by 100 mm wet medium + 100 mm gap + 100 mm wet medium, which will be denoted as 300 mm medium-gap-medium. Normal arrangement was experimentally studied for comparison with medium thicknesses of 100 and 300 mm, respectively. The result shows that the pressure drop of the 300 mm medium-gap-medium is lower than that of the normal medium at thicknesses of 300 mm and is close than that of 200 mm within the tested air speeds, and the cooling effectiveness of the 300 mm medium-gap-medium is higher than that of the normal medium at 200 mm but lower than that of the normal medium at 300 mm. Meanwhile, the correlations of pressure drop and heat transfer coefficient for the 300 mm medium-gap-medium are developed based on the test data. This study proves that the proposed 300 mm medium-gap-medium is feasible and shows superior performance when compared with normal medium at 200 mm thickness.

Tunable distributed SPR sensors with symmetrical structures excited by planar waveguides

Measurement ranges of the traditional surface plasmon resonance (SPR) sensors, which use intensity detection method and are excited by waveguides, are limited by the equivalent refractive index of the excited waveguide, not only makes it non-adjustable but also difficult to realize multi-range detection. To solve the above problems, tunable distributed SPR sensors with symmetrical structures excited by planar waveguides are designed. By studying several metrics of a metal-medium-metal SPR sensing structure exited by a planar waveguide, the influence of a metallic material’s thickness, and the medium thickness between the gold films on the measurement characteristics, are accordingly optimized to design the detection system. Double attenuation peaks can be generated under certain conditions, which embodies distributed sensing characteristics. Here, changing the resonance condition by changing the thickness of the measured medium between the metal films makes the measured refractive index range tunable. The planar waveguide with the Fermi refractive index distribution is prepared and the symmetrical sensing structures are arranged longitudinally alongside the direction of light propagation to achieve multiple attenuation peaks, and thus distributed sensing in different measured ranges is realized. The structure of different medium thicknesses excited by planar waveguides is used to test the honey solution with refractive indices varying between 1.33299 and 1.53246 in exciting the surface plasma waves with double attenuation peaks. For any refractive index range, the linear correlation coefficients are all above 0.99232, which demonstrates that the refractive index detection can be carried out within multiple ranges. This result constitutes a theoretical and practical basis for tunable distributed online measurement of the intensity SPR sensors.

P.780 Apathy and anxiety are early markers of Alzheimer's disease

Studies of radiation interactions with tissue equivalent material find importance in efforts that seek to avoid unjustifiable dose to patients, also in ensuring quality control of for instance nuclear medicine imaging equipment. Use of the Monte Carlo (MC) simulation tool in such characterization processes allows for the avoidance of costly experiments involving transmitted X- and γ-ray spectrometry. Present work investigates MC simulations of γ-ray transmission through tissue equivalent solid phantoms. Use has been made of a range of radionuclide gamma ray sources, 99mTc, 131I, 137Cs, 60Co (offering photons in the energy range from a few keV up to low MeV), popularly applied in medicine and in some cases for gauging in industry, obtaining the transmission spectra following their interaction with various phantom materials and thicknesses. In validation of the model, the simulated values of mass attenuation coefficients (μ/ρ) for different phantom materials and thicknesses were found to be in good agreement with reference values (NIST, 2004) to within 1.1% for all material compositions. For all of the primary photon energies and medium thicknesses of interest herein, results show that multiple scattering peaks are generally located at energies lower than 100 keV, although for the larger phantom thicknesses it is more difficult to distinguish single, double and multiple scattering in the gamma spectra. Transmitted photon spectra investigated for water, soft tissue, breast, brain and lung tissue slab phantoms are demonstrated to be practically independent of the phantom material, while a significant difference is observed for the spectra transmitted through bone that was proved to be due to the density effect and not material composition.

Medium-thickness-dependent proton dosimetry for radiobiological experiments

A calibration method was proposed in the present work to determine the medium-thickness-dependent proton doses absorbed in cellular components (i.e., cellular cytoplasm and nucleus) in radiobiological experiments. Consideration of the dependency on medium thickness was crucial as the linear energy transfer (LET) of protons could rise to a sharp peak (known as the Bragg peak) towards the end of their ranges. Relationships between the calibration coefficient R vs medium-layer thickness were obtained for incident proton energies of 10, 15, 20, 25, 30 and 35 MeV, and for various medium thicknesses up to 5000 μm, where R was defined as the ratio DA/DE, DA was the absorbed proton dose in cellular components, and DE was the absorbed proton dose in a separate radiation detector. In the present work, DA and DE were determined using the MCNPX (Monte Carlo N-Particle eXtended) code version 2.4.0. For lower incident proton energies (i.e., 10, 15 and 20 MeV), formation of Bragg-peak-like features were noticed in their R-vs-medium-layer-thickness relationships, and large R values of >7 and >6 were obtained for cytoplasm and nucleus of cells, respectively, which highlighted the importance of careful consideration of the medium thickness in radiobiological experiments.

Tire Splash and Spray Directly before and during Hydroplaning

ABSTRACT Wet roads can have a serious impact on tire traction. There are several ways of detecting wet roads; however, almost all of them come with disadvantages. Using the splash and spray behavior of the tire can offer a solution. To identify key parameters that influence splash and spray, we used high-speed cameras to record tires rolling on an internal drum tire test bench. The key parameters were water film thickness, speed, and profile geometry (tread pattern and tread depth). Our image-processing analysis showed three main effects in the splash and spray behavior that help to characterize the water film thickness: side splash, circumferential spray, and torrent spray. Circumferential spray and torrent spray can be used to estimate low and medium water film thicknesses, but these require information about speed and profile geometry. Side splash announces hydroplaning without the need for additional information.

Monte Carlo simulations and analysis of transmitted gamma ray spectra through various tissue phantoms

Studies of radiation interactions with tissue equivalent material find importance in efforts that seek to avoid unjustifiable dose to patients, also in ensuring quality control of for instance nuclear medicine imaging equipment. Use of the Monte Carlo (MC) simulation tool in such characterization processes allows for the avoidance of costly experiments involving transmitted X- and γ-ray spectrometry. Present work investigates MC simulations of γ-ray transmission through tissue equivalent solid phantoms. Use has been made of a range of radionuclide gamma ray sources, 99mTc, 131I, 137Cs, 60Co (offering photons in the energy range from a few keV up to low MeV), popularly applied in medicine and in some cases for gauging in industry, obtaining the transmission spectra following their interaction with various phantom materials and thicknesses. In validation of the model, the simulated values of mass attenuation coefficients (μ/ρ) for different phantom materials and thicknesses were found to be in good agreement with reference values (NIST, 2004) to within 1.1% for all material compositions. For all of the primary photon energies and medium thicknesses of interest herein, results show that multiple scattering peaks are generally located at energies lower than 100 keV, although for the larger phantom thicknesses it is more difficult to distinguish single, double and multiple scattering in the gamma spectra. Transmitted photon spectra investigated for water, soft tissue, breast, brain and lung tissue slab phantoms are demonstrated to be practically independent of the phantom material, while a significant difference is observed for the spectra transmitted through bone that was proved to be due to the density effect and not material composition.

Transmission versus reflectance spectroscopy for quantitation.

The objective of this work was to compare the accuracy of analyte concentration estimation when using transmission versus diffuse reflectance spectroscopy of a scattering medium. Monte Carlo ray tracing of light through the medium was used in conjunction with pure component absorption spectra and Beer-Lambert absorption along each ray's pathlength to generate matched sets of pseudoabsorbance spectra, containing water and six analytes present in skin. PLS regression models revealed an improvement in accuracy when using transmission compared to reflectance for a range of medium thicknesses and instrument noise levels. An analytical expression revealed the source of the accuracy degradation with reflectance was due both to the reduced collection efficiency for a fixed instrument etendue and to the broad pathlength distribution that detected light travels in the medium before exiting from the incident side.

A calibration method for realistic neutron dosimetry in radiobiological experiments assisted by MCNP simulation.

Many studies on biological effects of neutrons involve dose responses of neutrons, which rely on accurately determined absorbed doses in the irradiated cells or living organisms. Absorbed doses are difficult to measure, and are commonly surrogated with doses measured using separate detectors. The present work describes the determination of doses absorbed in the cell layer underneath a medium column (DA) and the doses absorbed in an ionization chamber (DE) from neutrons through computer simulations using the MCNP-5 code, and the subsequent determination of the conversion coefficients R (= DA/DE). It was found that R in general decreased with increase in the medium thickness, which was due to elastic and inelastic scattering. For 2-MeV neutrons, conspicuous bulges in R values were observed at medium thicknesses of about 500, 1500, 2500 and 4000 μm, and these were attributed to carbon, oxygen and nitrogen nuclei, and were reflections of spikes in neutron interaction cross sections with these nuclei. For 0.1-MeV neutrons, no conspicuous bulges in R were observed (except one at ~2000 μm that was due to photon interactions), which was explained by the absence of prominent spikes in the interaction cross-sections with these nuclei for neutron energies <0.1 MeV. The ratio R could be increased by ~50% for small medium thickness if the incident neutron energy was reduced from 2 MeV to 0.1 MeV. As such, the absorbed doses in cells (DA) would vary with the incident neutron energies, even when the absorbed doses shown on the detector were the same.

Lymphoscintigraphic imaging study for quantitative evaluation of a small field of view (SFOV) gamma camera

The Hybrid Compact Gamma Camera (HCGC) is a portable optical-gamma hybrid imager designed for intraoperative medical imaging, particularly for sentinel lymph node biopsy procedures. To investigate the capability of the HCGC in lymphatic system imaging, two lymphoscintigraphic phantoms have been designed and constructed. These phantoms allowed quantitative assessment and evaluation of the HCGC for lymphatic vessel (LV) and sentinel lymph node (SLN) detection. Fused optical and gamma images showed good alignment of the two modalities allowing localisation of activity within the LV and the SLN. At an imaging distance of 10 cm, the spatial resolution of the HCGC during the detection process of the simulated LV was not degraded at a separation of more than 1.5 cm (variation <5%) from the injection site (IS). Even in the presence of the IS the targeted LV was detectable with an acquisition time of less than 2 minutes. The HCGC could detect SLNs containing different radioactivity concentrations (ranging between 1:20 to 1:100 SLN to IS activity ratios) and under various scattering thicknesses (ranging between 5 mm to 30 mm) with high contrast-to-noise ratio (CNR) values (ranging between 11.6 and 110.8). The HCGC can detect the simulated SLNs at various IS to SLN distances, different IS to SLN activity ratios and through varied scattering medium thicknesses. The HCGC provided an accurate physical localisation of radiopharmaceutical uptake in the simulated SLN. These characteristics of the HCGC reflect its suitability for utilisation in lymphatic vessel drainage imaging and SLN imaging in patients in different critical clinical situations such as interventional and surgical procedures.

Experimental study of the application of two trickle media for inlet air pre-cooling of natural draft dry cooling towers

This paper is part two of a broader investigation into pre-cooling the air that enters natural draft dry cooling towers. Evaporative cooling of air is to some extent different from evaporative cooling of water. Two trickle media (Trickle125 and Trickle100) originally designed for evaporative cooling of water were studied in an open-circuit wind tunnel for evaporative cooling of air. Three medium thicknesses (200, 300 and 450mm) and two water flow rates (10 and 5l/minperm2 horizontally exposed surface area) were used in the tests. The air velocities ranged from 0.5 to 3.0m/s. The cooling efficiency and the pressure drop of the two media were curve fitted to yield a set of correlations. The pressure drop ranges for Trickle125 and Trickle100 were 0.7–50Pa and 0.6–41.6Pa, respectively. The cooling efficiencies of Trickle125 and Trickle100 fell within 15.7–55.1% and 11–44.4%, respectively. Generally, media with large effective surfaces provide high cooling efficiencies and high pressure drops; there is a trade-off between cooling efficiency and pressure drop when selecting a particular medium for a specific application. The water entrainment off the media was detected with water-sensitive papers, and both media had severe water entrainment at large air velocities.

Midsole Thickness Affects Running Patterns in Habitual Rearfoot Strikers During a Sustained Run

The purpose of this study was to: (1) investigate how kinematic patterns are adjusted while running in footwear with THIN, MEDIUM, and THICK midsole thicknesses and (2) determine if these patterns are adjusted over time during a sustained run in footwear of different thicknesses. Ten male heel-toe runners performed treadmill runs in specially constructed footwear (THIN, MEDIUM, and THICK midsoles) on separate days. Standard lower extremity kinematics and acceleration at the tibia and head were captured. Time epochs were created using data from every 5 minutes of the run. Repeated-measures ANOVA was used (P < .05) to determine differences across footwear and time. At touchdown, kinematics were similar for the THIN and MEDIUM conditions distal to the knee, whereas only the THIN condition was isolated above the knee. No runners displayed midfoot or forefoot strike patterns in any condition. Peak accelerations were slightly increased with THIN and MEDIUM footwear as was eversion, as well as tibial and thigh internal rotation. It appears that participants may have been anticipating, very early in their run, a suitable kinematic pattern based on both the length of the run and the footwear condition.

Measurement of nonlinear refraction of thick samples using nonlinear-imaging technique with a phase object

Abstract The third-order nonlinear refractive index of carbon disulfide (CS2) with different thicknesses is measured by a nonlinear-imaging technique with a phase object (NIT-PO). The propagating characteristics of the laser beam within thick medium are analyzed by numerically solving the electromagnetic wave equation. By theoretically calculating, we study the relationship of the phase shift induced by nonlinear refraction versus medium thicknesses. Fitting the output image with the help of the effective interaction length, the nonlinear refractive index n2 of CS2 can be determined, which suggests a one-single-shot method for the investigation of optical nonlinearity in thick medium.