Abbe Refractometer Research Articles

Effect of lateral substituents on the properties of polymerisable liquid crystals with bistolane core

ABSTRACT A new series of polymerisable liquid crystals based on bistolane core and different lateral substituent groups (F, Cl, CH3 and C2H5) were synthesised and characterised by1H-NMR and13C-NMR. The properties of these compounds were tested by DSC, POM and Abbe refractometer. The results indicate that all of these compounds display a stable nematic phase, and the introduction of lateral substituents has a significant impact on the phase behaviour and birefringence. As the size of lateral substituents gradually increases the clearing point and birefringence of the liquid crystals both show a decreasing trend. The birefringence of these new compounds reaches 0.36 ~ 0.49, which is about 2 ~ 3 times that of the commercial compounds RM257. These new polymerisable liquid crystals with extremely high birefringence provide a choice for developing devices based on planar optics.

Structural and Spectroscopic Studies of Sm3+ Ions Doped ZnS Nanoparticle in Silica Glass Matrix

Objective: This report intends to study the structural and spectroscopic properties of Sm3+ doped with ZnS nanoparticles in silica glass. Methods: The research adopted the sol-gel technique for preparing the sample. The physical property of the studied glass sample is examined by different characterization techniques such as Abbe refractometer, X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) and Photoluminescence (PL) spectroscopy. Findings: XRD studies confirmed the formation of glassy amorphous nature and TEM studies confirmed that the studied nanoparticles are polycrystalline in nature with a particle size lies between 10-50 nm after annealing at 300 °C. The PL spectra have three emission bands that correspond to 4G5/2→6H5/2, 4G5/2→6H7/2 and 4G5/2→6H9/2 correspondingly at 565 nm, 603 nm and 650 nm with most prominent bands in the orange-red region. Novelty: This research proves that the rare earth element can be successfully doped with semiconductor nanoparticle by using sol-gel technique in silica glass. Consequently, the doped glass can be utilised for producing nearly pure white hue when triggered at 370 nm. Keywords: Samarium, ZnS, XRD, TEM, PL, CIE Chromaticity

High-Δn tolane-liquid crystal diluters with low melting point and low rotational viscosity

High birefringence (Δn) and low melting point (Tm), high Δn and low rotational viscosity (γ1) are two pairs of contradictory performance parameters. In this work, two high-Δn LC diluters 3PTPF2V and 3PTPFOV are proposed to achieve a fine balance between them. These target compounds containing a rigid tolane core, a lateral fluorine substituent and a buty-3-enyl or allyloxy terminal group were further synthesized. Some experimental instruments, such as POM, DSC, Abbe refractometer, multi-channel liquid crystal evaluation system, were adopted to investigate their properties of mesomorphic phase behavior, Tm, Δn and γ1 by comparing with classical LC diluters 3HHV and V2PTP2V. Meanwhile, density functional theory (DFT) calculations were employed to correlate the experimental results, and their comprehensive effects on two high-Δn LC mixtures were further evaluated. Research results indicated that both target compounds possess low Tm (∼20 °C), low γ1 (∼6.5 mPa·s), and high Δn (>0.26). Performance in high-Δn LC mixture demonstrated that they could effectively decrease Tm and γ1, meanwhile maintain high Δn and Tc values, meaning their potential application prospects in fast-response LC optical devices.

Application of non-destructive fast methods for quality assessment of sunflower oil

The sunflower oil is pressed from the seeds of the sunflower plant (Helianthus annuus). It contains high amounts of the essential fatty acid, linoleic acid. Sunflower oil is commonly consumed in foods. The quality of sunflower oil depends on the quality of the sunflower seeds to be processed, the storage conditions of the seeds before pressing and the refining conditions. The standard chemical methods used to determine the chemical content of the oils are usually time-consuming,labor-intensive and expensive. Therefore, we have tested four physical methods measuring refractive indices and their dispersion curves, color parameters, UV-VIS spectroscopic and fluorescence spectra that are related to the chemical structure and composition of the sunflower oils. The refractive indices of the samples were measured using a laser refractometer at wavelengths of 405 nm, 447 nm, 532 nm and 656 nm. The dispersion curves and the dispersion parameters were approximated using one-term Sellmeier model. The color parameters were obtained using a Lovibond PFX 880 spectrophotometer. The values for the refractive indices were compared to these, obtained by a standard method using the Abbe refractometer. These methods are fast, easy to perform and do not require any additional chemical agents. Four groups of sunflower oils – cold pressed, oil with added antioxidants and commercially refined and nonrefined sunflower oil, were investigated.

Chromatic dispersion and thermal coefficients of hygroscopic liquids: 5 glycols and glycerol

Chromatic dispersion and thermal coefficients of 6 hygroscopic liquids: ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol (propane-1, 2-diol), and glycerol were measured in the range from 390 to 1070 nm for temperatures from 1 to 45 °C. A modified Abbe refractometer was utilised. Special care was taken to avoid contaminating the liquids under the test with water and solid particles. The measurement uncertainties were analysed. It was noticed that (in the given range and within the available measurement accuracy) the dependence of the refractive indices on the wavelength and temperature could be considered independently. Thus, thermal coefficients were found for each wavelength used, and their weak dependence on the wavelength was recognised. Then the Sellmeier equation was fitted to the experimental results for each temperature.

Impact of Quantum Dots on Refractive Index of Nematic Liquid Crystal Polymer System

In the present study the effect of two quantum dots ZnS and CdSe on the Refractive Index of Nematic Liquid Crystal Polymer System (NLCPS) is investigated and compared. The measurement was performed for both the systems separately, using an Abbe Refractometer, within a temperature range of 20°C to 80°C with wavelengths in the visible spectrum. The refractive index with respect to temperature for various wavelengths was studied. We observed that the response of ZnS quantum dots dispersed in NLCPS was found to be better as compared to the CdSe system. This study may be useful for display and sensor applications.

Study on the Physical, Optical and Luminescence Properties of the Cr-Doped Recycled Waste Glass

The rapid economic growth in recent years has led to the use of glass material in many activities, resulting in a large amount of glass waste. The efficient use of waste glass recycling has gained increasing attention. Researchers propose a method for recycling waste glass to reduce glass manufacturing costs and investigate the physical, optical, and luminescence properties of chromium oxide-doped glass with the stoichiometry of (35-x) B2O3: 35SiO2 (use waste glass as SiO2): 12Na2O: 7.9CaO: 0.1Sb2O3: 10BaO: xCr2O3 when x = 0.00 to 0.05 mol%. Glass was synthesized using the melt quenching at 1,200 degrees Celsius for 3 h. Archimedes’ principle and the Abbe refractometer were used to calculating density and refractive index decrease with the addition of 0.01 mol% of Cr3+ concentration. At room temperature, absorption spectra were analyzed using a UV-VIS-NIR spectrometer exhibiting two broadband at 438 and 625 nm intense bands, and the luminescence properties of the Cr3+ glasses system were investigated using an excitation wavelength of 567 nm, with luminescence peaks observed around 750 nm. CIE L* a* b* shows the green color.

Evaluation of the refractive indices of pure organic dyes using binary mixture models

The refractive index (RI) of organic dyes is highly important due to their applications in many optical and optoelectronic fields. Because the refractive indices of various organic dyes are unknown, in the present work, we have developed an easy and simple method to estimate the refractive indices of pure organic dyes using binary mixing rules. The refractive indices were measured at a temperature of 20 °C for a wavelength λ = 589.6 nm with an Abbe refractometer. The method was previously checked for two compounds with known refractive indices, Xylene and Fluorescein, both solved in ethanol. According to the acquired results, it can be stated that Arago-Biot and Gladstone-Dale mixing rules best check the RI. Afterward, this method was applied to the Phloxine B, diluted in ethanol, to determine its unknown RI. The obtained experimental refractive index data of Phloxine B + ethanol solutions at higher ethanol mole fractions were correlated satisfactorily with both models.

Chromatic dispersion of soft contact lens materials

PurposeTo investigate and evaluate the chromatic dispersion of various hydrogel and silicon hydrogel contact lens materials. MethodsEighteen different soft contact lens materials with high and low water content in lens power of −1.00 DS were measured by one operator at temperature of 20 °C ± 0.5° soaked in ISO standard phosphate-buffered saline (PBS) and in their respective packaging solutions (PS). An analogue Abbe refractometer (Model Zuzi 320, AUXILAB, S.L., Navarra, Spain) was used for refractive index (RI) measurements at 5 different wavelengths. All contact lenses were presented in a random and masked order to the operator. The Bland-Altman method with 95 % limits of agreement (LoA) and coefficient of repeatability (CoR) was used to characterise the repeatability of refractive index measurements. The Abbe numbers for each material were calculated by entering the measured and interpolated refractive indices into the Abbe number equation. One-way ANOVA analysis was used to test if there were significant differences between the 5 different wavelengths (470 nm–680 nm) within each material. An unpaired t-test was used to determine if there were differences in refractive index or dispersion between packaging solution and PBS results. ResultsNelfilcon A (Dailies Aqua Comfort Plus) soaked in PS showed the best repeatability of all 18 examined soft contact lenses across all wavelengths with an average refractive index of 1.3848 for all 6 contact lenses with a standard deviation of 0.00064. The 95 % limits of agreement were between 1.3835 and 1.3860. The mean coefficient of repeatability for nelfilcon A was 0.00125. For contact lenses soaked in ISO Standard PBS comfilcon A (Biofinity) had the best repeatability. The average refractive index of all 6 contact lenses was 1.4041 with a standard deviation of 0.00031 and a coefficient of repeatability of 0.00060. The 95 % limits of agreement were between 1.4035 and 1.4047. The analysis with One-way ANOVA with multiple comparisons involving Holm-Sidak post-hoc, showed that there are significant differences (p < 0.001, Fratio = 376.2 between wavelengths and Fratio = 1559 between different refractive indices) in the refractive index of most common lens materials across the visible wavelength range. Based on unpaired t-test, there is no significant difference (p > 0.05) in the Abbe numbers of the tested lens materials whether they have been placed in the packaging solution or in standard PBS (p > 0.05, 95 % CI = −4.8070 to 5.8680, t = 0.2054). The Abbe numbers for the calculated contact lenses soaked in PS ranged between 43.7 and 89.9. For contact lenses stored in PBS the range was between 46.3 and 81.6. ConclusionThere is a good repeatability between repeated RI measurements taken from the same lens and from the same material. The significant differences between the refractive indices across the 5 different wavelengths showed the presence of chromatic dispersion in the 18 evaluated soft contact lens materials. Furthermore, it could be shown that there is no significant difference in dispersion whether the contact lenses are soaked in standard PBS or in their respective packaging solutions. With no other published data available as a reference, absolute accuracy of the calculated Abbe numbers remains to be confirmed, however, this study did confirm that significant chromatic dispersion exists in soft contact lens materials.

Refractive index measurement of uniform liquid using an improved laser speckle method

Based on the refraction characteristic of uniform and transparent liquid, the measurement error of the liquid refractive index using the internal standard method is analyzed, and an improved laser speckle method is proposed. This method designs a double-cell structure composed of two identical rectangular parallelepiped glass cells with one cell containing the liquid to be measured and the other one being empty. This double-cell structure is placed in the built optical system based on laser speckle, and then the refractive indices of sodium chloride solution and sucrose solution with various concentrations are measured by the improved method. Compared with the measurement values of the Abbe refractometer and the internal standard method, the results show that the improved method can significantly reduce the measurement error and improve the measurement accuracy.

Standardisation of Vilwadi Leha - A Process Validation Based on Total Solid Method

Standardisation can be defined as a process of enforcing a level of consistency or uniformity in pharmaceutical preparations which are operated within the selected environment. Vilwadileha is a well-known Ayurvedic polyherbal formulation used for the management of various diseases such as Chardi, Arochaka, Praseka, Agnimandhya etc. It is described in Sahasrayoga leha prakarana. Aim: The objective was to develop the standard manufacturing procedure (SMP) and quality standards of Vilwadi leha based on total solid method. Total soluble solids content of a solution is determined by the index of refraction using either hand refractometer or Abbe refractometer. Brix is the term used when a refractometer equipped with scale, measures total soluble solids of a pure aqueous sucrose solution by the aid of refractive indices at 20°C and percentage by mass. Materials and methods: In present work, VL was prepared in three batches as per standard guidelines mentioned in AFI Vol 2. Results: Samyak leha paka lakshanas observed was compared with brix value and fix the brix value of VL prepared in 3 Batches. It took 10.40hr to completion of preparation. Conclusion: The current study opens a new concept to standardise Avaleha. This is a trial work to standardise the Leha paka with total solids analysis method or brix value. Brix for each preparation may differ based on sucrose concentration. It was found that Leha prepared with TS between 75 and 77 had parameters similar to Samyak Leha paka. Attempts were also made to develop analytical profile of final product.

Effects of polishing procedures on optical parameters and surface roughness of composite resins with different viscosities.

The aims of this study were to evaluate the optical properties of flowable and injectable composites after polishing, such as translucency (translucency parameter [TP], TP00), opalescence (OP-BW), chroma (C*ab), refractive index (RI), and change in surface roughness (Ra, Rz). Ninety disc-shaped samples were prepared from micro-hybrid, flowable, and injectable composites and divided into 3 groups according to the polishing systems (n=10). The RI was measured with an Abbe refractometer, and optical measurements were performed with a spectrophotometer. The surface roughness was measured with a two-dimensional profilometer. Data were analyzed with the generalized linear model method and two-way analysis of variance. The results showed that the polishing procedure did not significantly impact the RI (p=0.987). Injectable composite had the highest translucency (TP=28.67; TP00=13.49) and opalescence (OP-BW=13.11); showed the lowest C*ab value (17.95). Also, the effects of the composite type and polishing procedure on surface roughness were statistically significant (p=0.047 and p<0.001).

Scrutinizing the physical, structural, elastic, optical and gamma ray shielding properties of Samarium ions infused Niobium Bariumtelluroborate glasses

The present work reports the physical, structural, elastic, optical, and radiation shielding studies on (80˗X)H3BO3+10TeO2+9.5Nb2O5+XBaO+0.5Sm2O3 (where X = 10, 20, 30, 40, 50 in wt%) glasses which is prepared by the melt quenching technique. The bending and stretching vibrations of the different compounds used are analyzed through FTIR instrumentation. The density and refractive indices are measured experimentally following Archimedes's principles and by using Abbe's refractometer, respectively. Various structural parameters are calculated to resolve the actual placement of atoms in the glass complex, which explains the compactness of the network. Elastic properties of the synthesized glasses are calculated to estimate the resistance of glass under stress. Additionally, the optical band gap is calculated, and the nature of bonds in the network is ionic compared to the covalent nature. Boron–Boron distance is the lowest for 50BNTBSm sample. The decrease in OPD content is linked with the decrease in the number of oxygen atoms, for 10BNTBSm and 50BNTBSm glasses, it is 289 and 209 oxygen atoms, respectively. Λth value is high for 10BNTBSm glass sample with the minimum BaO reinforcement. The Urbach's energy varies from 0.534 to 0.967 eV, corresponding to xBNTBSm samples indicating fewer defects in the glasses. Moreover, gamma-ray and fast neutron attenuation properties of xBNTBSm are determined and compared with numerous shielding materials such as concrete and other types of glasses. Results showed that replacing 40% of H3BO3 with BaO leads to a net improvement in gamma-ray attenuation properties. However, this situation was the opposite in the fast neutron absorption properties. A clear superiority of sample 50BNTBSm was also reported against the compared absorbent materials. It can be concluded that replacing 40% of H3BO3 with BaO would provide some significant improvements to Niobium Bariumtelluroborate glasses.

A new interpretation of the optical interference figures observed in a lyotropic biaxial nematic phase for a ternary mixture of DTMABr, 1-DDeOH and H2O

The lyotropic ternary mixture of dodecyltrimethylammonium bromide (DTMABr), 1-dodecanol (DDeOH) and water (H2O) was studied by optical conoscopy and Abbe refractometer techniques. The present mixture showed a large biaxial phase domain (NB) located between two different uniaxial ones in the partial phase diagram, one optically positive (ND) and the other negative (NC). The NB phase exhibits two optic signs as a function of the temperature , each of which was equal to the neighboring uniaxial phases. The temperature dependence of the refractive indices was measured along the NC-NB-ND phase transitions. In addition, we are reporting for the first time a new interpretation of the optical interference figures observed along the NB phase.

Visual Assessment of Blood Plasma versus Optical Transmittance and Refractive Index Measurements for Quantifying Lipemia.

Today, visual classification of the degree of lipemia in blood samples is frequently performed in clinical laboratories. However, achieving standardization of this classification at low cost and with fewer resources is an objective that is still under development. In this work, a comparison is made between the visual inspection and optical measurements of blood plasma for quantifying lipemia. The plasma refractive index’s real part was measured using an Abbe refractometer and transmittance measurements were made at a 589 nm wavelength and wavelengths ranging from 320 to 1100 nm in the spectral region, respectively. Taking the slope of the transmittance spectrum at two specific wavelengths, it is possible to establish a more standardized selection criterion and implement it quickly using low-cost optical devices. Furthermore, using the proposed transmittance-spectrum-slope method, statistically significant differences (p < 0.05) were found between healthy blood samples and lipemia 1, 2, 3, and 4. However, there were no statistical differences between lipemia 1 and 2.

Stable-Phase Diagram of the Quaternary Water–Salt System K+, Rb+, Cs+//SO42––H2O at T = 323.2 K

The stable-phase equilibria of the aqueous quaternary system K+, Rb+, Cs+//SO42––H2O was investigated at T = 323.2 K using the isothermal dissolution equilibrium method. The solubility, density, and refractive index of equilibrium solutions were determined using the chemical/instrument analysis method, the specific gravity bottle method, and the WYA Abbe refractometer, respectively. The solid phases were identified by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results reveal that besides three single salts (K2SO4, Rb2SO4, and Cs2SO4), three complete solid solutions are formed in this system at 323.2 K, namely, [(Kx, Rb1–x)2SO4], [(Kx, Cs1–x)2SO4], and [(Rbx, Cs1–x)2SO4], increasing the difficulty of separation potassium from the solution composed of rubidium, cesium, and sulfate. The stable-phase diagram of the quaternary system K+, Rb+, Cs+//SO42––H2O at T = 323.2 K consists of four invariant points, nine univariant curves, and six crystallization regions. The sequence of the size of the salt crystal region is [(Kx, Rb1–x)2SO4] > [(Kx, Cs1–x)2SO4] > K2SO4 > [(Rbx, Cs1–x)2SO4] > Rb2SO4 > Cs2SO4. The phase diagrams at different temperatures (T = 298.2 K and T = 323.2 K) show that temperature is an important factor affecting salt crystallization, especially for the solid solution. As the temperature increases, the crystallization region of [(Kx, Cs1–x)2SO4] conspicuously decreases, whereas the crystallization regions of [(Kx, Rb1–x)2SO4] and [(Rbx, Cs1–x)2SO4] increase slightly.

The Dispersion Staining Technique and Its Application to Measuring Refractive Indices of Non-opaque Materials, with Emphasis on Asbestos Analysis

Refractive index (RI) is the most important optical property of non-opaque materials. It is the leading diagnostic optical property of non-opaque materials, especially asbestos minerals. Dispersion staining (DS) has been proven to be the most effective technique with desirable accuracy for the measurement of asbestos minerals’ RI using the immersion method by polarized light microscopy (PLM). This paper presents a practical procedure for this measurement. To facilitate the analysis, two comprehensive suites of pre-calculated look-up tables for the conversion of the observed matching wavelength to RI were constructed for the two major types of RI liquids: Cargille Laboratories (Cargille) and Delaware Research Institute of Microscopy and Material Characterization LLC (DRIMMC), respectively, covering the range of RI liquids suitable for analyzing the six regulated asbestos minerals. RI liquid calibration in the absence of an Abbe refractometer is discussed. An alternative solution using Cargille optical glass standards is proposed, and two comprehensive suites of pre-calculated look-up tables for both Cargille and DRIMMC liquids are included, covering the range of RI liquids routinely used in the analysis of the six regulated asbestos minerals.

Study on the Changes of Main Ingredients of Acacia Honey during the Ripening Process Based on Clustering Analysis and Principal Component Analysis

In order to explore the changes in nutritional ingredients of honey during the natural ripening process, the contents of moisture, monosaccharide, disaccharide, 9 kinds of oligosaccharides and 18 kinds of polyphenols in acacia honey were determined by the Abbe refractometer, high performance liquid chromatography(HPLC), gas chromatography-mass spectrometry(GC-MS) and high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS), respectively, combined with hierarchical cluster analysis(HCA) and principal component analysis(PCA) to distinguish acacia honey during different ripening days. The results showed that during the ripening process of acacia honey, the contents of moisture, oligosaccharides and polyphenols changed significantly. Among them, the contents of moisture, kestose, and melezitose decreased by 5.77, 0.09, and 3.47 g/100 g, respectively, while maltulose, turanose, erlose, and isomaltose increased 0.85, 1.65, 2.43, and 0.25 g/100 g, respectively. For the polyphenols, the contents of rutin, kaempferol, protocatechuic acid, and p-hydroxybenzoic acid generally increased; gallic acid, morin, ferulic acid, galangin, caffeic acid phenethyl ester, caffeic acid, and chrysin increased first and then decreased; benzoic acid and p-coumaric acid decreased first and then increased. In addition, the contents of melezitose under different ripening days of acacia honey were reduced significantly(P<0.05), while p-hydroxybenzoic acid and caffeic acid increased significantly(P<0.05), which could be used as potential characteristic indexes for judging the ripeness of acacia honey. The chemometrics analysis results showed oligosaccharides and polyphenols could obviously distinguish acacia honey during the different ripening days.

Etched fiber Bragg grating probe using a regular CNC machine and a 3D printer

Etched fiber Bragg gratings (EFBGs) have been widely employed for refractive index (RI) measurements that can be used to monitor sugar consumption during the fermentation of alcoholic beverages. EFBGs are obtained by removing the cladding of a fiber Bragg grating, which is traditionally performed by a chemical attack with hydrogen fluoride, an extremely hazardous corrosive substance that causes severe wounds and even death. To overcome such drawbacks, this technical note presents a simple, practical, and low cost method for the diameter reduction of single mode optical fibers by mechanical polishing, employing a small scale computer numerical control device and an ad hoc 3D-printed rod. The sensor probe obtained was tested using sucrose aqueous solutions with RIs between 1.333 and 1.394, measured in an Abbe refractometer. The results show a linear shift of the Bragg wavelength with respect to RI with a correlation of 0.928.

Development of new diacrylate monomers as substitutes for Bis-GMA and UDMA

ObjectiveBisphenol A-glycidyl methacrylate (Bis-GMA) and urethane dimethacrylate (UDMA) are widely used as the primary components of (meth)acrylic monomers. However, the use of Bis-GMA, which is a bisphenol A derivative, in dentistry is being questioned after bisphenol A was found to exhibit estrogenic activity. Although UDMA is being considered as a substitute for bis-GMA, the mechanical properties of cured resin composites containing UDMA are less than desirable. Therefore, in this study, we developed new alternative (meth)acrylic monomers to enhance the mechanical strength of cured composite resins. MethodsFive urethane acrylic monomers were synthesized in this study as (meth)acrylic monomer substituents to replace Bis-GMA and UDMA. The elastic modulus, strength, and breaking energy values of cured resins consisting of mixtures of the urethane acrylates and diluting monomers were determined using the three-point flexural test. The data obtained were analyzed using one-way ANOVA and the post-hoc Tukey HSD tests (p < 0.05). Viscosities of the urethane acrylic monomers were measured with a cone-plate viscometer. Refractive indices of the urethane acrylic monomers were determined with an Abbe refractometer. ResultsThe results of the three-point flexural tests revealed that the cured urethane acrylic monomer-based resin exhibited higher elastic modulus (up to 40%) and strength (up to 21%) compared to the cured UDMA-based resin. Viscosity and refractive index of the urethane acrylic monomers were between those of UDMA and Bis-GMA. SignificanceThe developed urethane diacrylates prepared from diisocyanates which have an aromatic or aliphatic ring, 1,3-bis(1-isocyanato-1-methylethyl)benzene (TMXDI), 1,3-bis(isocyanatomethyl)benzene (XDI), or norbornane diisocyanate (NBDI) are worth considering as alternative options of Bis-GMA and UDMA for restorative resin composites.