Miracle-dz/UniFAR-FTUs huggingface dataset:
Geometry-Based Camera Calibration Using Closed-Form Solution of Principal Line

Camera calibration is a crucial prerequisite in many applications of computer vision. In this paper, a new geometry-based camera calibration technique is proposed, which resolves two main issues associated with the widely used Zhang’s method: (i) the lack of guidelines to avoid outliers in the computation and (ii) the assumption of fixed camera focal length. The proposed approach is based on the closed-form solution of principal lines with their intersection being the principal point while each principal line can concisely represent relative orientation/position (up to one degree of freedom for both) between a special pair of coordinate systems of image plane and calibration pattern. With such analytically tractable image features, computations associated with the calibration are greatly simplified, while the guidelines in (i) can be established intuitively. Experimental results for synthetic and real data show that the proposed approach does compare favorably with Zhang’s method, in terms of correctness, robustness, and flexibility, and addresses issues (i) and (ii) satisfactorily.
Discoloration of Green Copper Pigments in Manuscripts and Works of Graphic Art

Many important historical objects in libraries and archives, mainly illuminated manuscripts, documents, coloured prints and maps, show serious damage as a result of the destructive effects of pigments and inks. These documents therefore are acutely endangered. These deterioration phenomena are often caused by green copper-based pigments. Only few cases are known in which the blue copper pigment azurite — causes paper to decompose. The degree of damage ranges from colour change in painted areas to total destruction of pigments and carrier materials, papyrus, paper and parchment. This destruction occurs in several stages. The green colour bleeds through the sheet, usually followed by an intensive browning of the painted area. Finally, the support becomes extremely brittle. Handling of objects in this state leads to perforation and losses (Fig. 1). Besides the destructive action of green pigments, copper alloys usually brass that have been used to imitate gilding, similarly destroy paper objects. The chemical mechanism of the destruction phenomena was not fully understood for a long time, although numerous theories have been proposed to explain the decay of papyrus, paper and parchment documents. This is not astonishing, as there are many possible chemical reactions between copper pigments, binding media and the paper or parchment support. The chemical mechanisms of these processes are complex. The desire to preserve these items necessitates the development of effective treatment methods, which is only possible after the chemical reasons for deterioration are clarified. The destructive mechanism of copper-based pigments is the result of a complex overlapping of different processes: the natural aging of paper, the composition of pigments or, occasionally, metallic leaves and their ability to create chemical reactions with the carrier or the medium. These processes are strongly influenced by pollution and by environmental and storage conditions, especially temperature and humidity. In the destruction of paper, sizing and inorganic fillers also play an important role. Scientific research attempts to unravel the chemical mechanisms of degrada-
Synthesis and structural study of new highly lipophilic 1,4-dihydropyridines

A new series of 1,4-dihydropyridines (1,4-DHPs) endowed with ester groups bearing long and functionalised alkoxy chains at the C3 and C5 positions of the nitrogen ring have been prepared from the corresponding β-keto esters which were in turn prepared by a lipase catalysed transesterification reaction. The structural study has been carried out by X-ray crystallography and theoretical calculations at the semiempirical (AM1), ab initio (HF/6-31G*) and B3LYP/6-31G* levels and reveals that the long alkyl chains do not have any influence on the required geometry of the 1,4-DHPs for biological activity. However, these chains have a strong impact on the lipophilicity and, therefore, they could be used to gain a better control of the duration of the pharmacological action.
Perceived Usage and Benefits of Metacognitive Strategies by University Students

Currently, the use of metacognitive strategies by students is highly being encouraged for their effective learning. Metacognitive strategies are those learning devices which become learners’ need for their optimal learning. Likewise, metacognitive strategies enable learners to become more confident, skillful, self-evaluator, and more independent by managing and directing their learning process at their own in the best way. Considering the benefits of using metacognitive strategies for students, the theme has not been qualitatively explored about the use of strategies by the students in universities of Pakistan. The purpose of this research work is to explore the perceived use, the extent of use, and benefits of metacognitive strategies by university students in Multan City. Survey research design was used for the accomplishment of the objectives. All students of three public sector universities of Multan city were selected as population. Qualitative data were analyzed through content analysis. The process started by tracing themes, followed by calculation of frequencies and percentages of students’ opinions to explore the frequency of use, extent of use, benefits, and awareness about using metacognitive strategies by university students. For calculation of frequencies and percentages, basic statistics was used. The results found that summarization, highlighting, note taking, bulleting and the concept mapping are the most frequently used learning strategies by university students. It was further found that most of the students use metacognitive strategies during exams, quizzes and tests, but their learning process was improved by using metacognitive strategies. It was recommended for the teachers to promote usage of group learning, discussion method and book reading habits among students and for the policy makers and teachers to create awareness about the frequent use, benefits and importance of metacognitive strategies in the improvement of university students’ learning.
Interplay Between Thin Film Ferroelectric Composition, Microstructure and Microwave Phase Shifter Performance

One of the keys to successfully incorporating ferroelectric films into Ku-band (12 - 18 GHz) phase shifters is to establish the composition, microstructure and thickness required to meet the tuning needs, and tailor the film properties to meet these needs. Optimal performance is obtained when the film composition and device design are such that the device performance is limited by odd mode dielectric losses, and these losses are minimized as much as possible while still maintaining adequate tunability. The parameters required to maintain device performance will vary slightly depending on composition, but we can conclude that the best tuning-to-loss figures of merit (K-factor) are obtained when there is minimal variation between the in-plane and out-of-plane lattice parameters, and the full-width half maximum values of the BSTO (002) peaks are less than approximately 0.04. degrees. We have observed that for phase shifters in which the ferroelectric crystalline quality and thickness are almost identical, higher losses are observed in films with higher Ba/Sr ratios. The best performance was observed in phase shifters with Ba:Sr = 30:70. The superiority of this composition was attributed to several interacting factors: the Ba:Sr ratio was such that the Curie temperature (180 K) was far removed from room temperature, the crystalline quality of the film was excellent, and there was virtually no difference between the in-plane and out-of-plane lattice parameters of the film.
Rapid Fabrication of Two‐ and Three‐Dimensional Colloidal Crystal Films via Confined Convective Assembly

We have developed a self‐assembly method for fabricating well‐ordered two‐dimensional (2D) and three‐dimensional (3D) colloidal crystal films. With a minute amount of a polystyrene colloidal suspension and without any special equipment, the proposed method can be used to rapidly deposit high‐quality colloidal crystal films over a large surface area. By controlling the lift‐up rate of the substrate, we modulate the meniscus thinning rate, which determines whether the colloidal particles are assembled into two or three dimensions. The proposed method can be used to fabricate not only monolayered colloidal crystals with colloidal particles of various sizes, but also multilayered colloidal crystals. In addition, the method enables us to fabricate binary colloidal crystals by consecutively depositing large and small particles.
Theoretical Elucidation of DPPH Radical-Scavenging Activity Difference of Antioxidant Xanthones

As naturally occurring polyphenols, xanthones are rather active in scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. By means of quantum chemical calculation, we reveal that the activity difference of xanthones canbe elucidated by their different O-H bond dissociation enthalpies (BDEs) and can be further explained in terms of electronic effect and intramolecular hydrogen bond effect of substituents. The unique structure of xanthones enables them to be promising antioxidants with advantages of rather low O-H BDE and relatively high ionization potential.
Toward a Systematic Understanding of Photodetectors Based on Individual Metal Oxide Nanowires

We present a set of criteria to optimize photodetectors based on n-type metal oxide nanowires and a comparison methodology capable of overcoming the present lack of systematic studies dealing with such devices. The response of photoconductors is enhanced following different fabrication strategies, such as diminishing the distance between the electrical contacts, increasing the width of the photoactive area, or improving the electrical mobility of the nanomaterials. The validity of the theoretical background is verified by experimental results obtained with devices based on ZnO nanowires. The performances of our devices show that the normalized gain of single ZnO nanowire-based photodetectors exceeds those of thin films.
Polytetrahydrofuran amphiphilic networks. I. Synthesis and characterization of polytetrahydrofuran acrylate ditelechelic and polyacrylamide‐l‐polytetrahydrofuran networks

A series of novel amphiphilic polyacrylamide-l-polytetrahydrofuran (PAm-l-PTHF) networks were prepared by the free-radical copolymerization of hydrophobic ditelechelic polytetrahydrofuran acrylate (PTHFDA) with hydrophilic acrylamide. PTHFDA was synthesized by acrylation of the corresponding hydroxycapped PTHF with acrylic acid in cyclohexane. After acrylation, there was no significant difference in the molecular weights and molecular weight distributions between the original PTHF and the resulting PTHFDA. Network structures and compositions were characterized by elemental analyses, Fourier transform infrared, differential scanning calorimetry, scanning electron microscopy, and swelling data. The networks can swell both in organic solvents and in water, which indicates that they are amphiphilic. The swelling of the networks in different solvents is composition-dependent. According to differential scanning calorimetry, scanning electron microscopy, and swelling tests, the networks have a microphase-separated and bicontinuous morphology.
Crystallization behavior of P(EN-co-ET) copolyesters: Crystallization kinetics and morphology revealed by DSC, time-resolved SAXS analysis, and TEM

The crystallization kinetics and morphology of PEN/PET copolyesters were investigated using differential scanning calorimetry (DSC), time-resolved small-angle X-ray scattering (TR-SAXS), and transmission electron microscopy (TEM). The Avrami exponents obtained using DSC were approximately 3 for homo PEN and 4 for all the copolyesters. The 3-parameter Avrami model was successfully fitted to the invariants with respect to the time obtained from TR-SAXS, and the exponent values were similar to those obtained from DSC. Moreover, the Avrami rate constants obtained from TR-SAXS showed marked temperature-sensitive decreases in all samples, like those obtained from DSC. This indicates that not only could changes in morphological parameters be obtained from the analysis of TR-SAXS data but also crystallization kinetics. The changes in the morphological parameters determined from the SAXS data indicate that the minor components, dimethyl terephthalate (DMT) segments, are rejected into the amorphous phase during crystallization. In the TEM study, copolyesters crystallized at temperature above 240 °C grew into both the α- and β-form, although 240 °C is the optimum condition for the β-form crystal. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 805–816, 2005
The Effect of Process Parameters on the Pervaporation of Alcohols through Organophilic Membranes

Abstract Several organophilic membranes were utilized to selectively permeate ethanol, n-butanol, and t-butanol from dilute aqueous mixtures using pervaporation (PV). Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) membranes were utilized to investigate the effect of temperature, pressure, and start-up/transient time on the separation of aqueous ethanol mixtures. Results indicate optimal ethanol selectivity and flux at the lowest permeate-side pressure. Increased temperature significantly enhanced the productivity of PTMSP, but extended operation of the PTMSP membranes at high temperatures resulted in flux degradation. Two other hydrophobic membranes, poly(dimethyl siloxane) (PDMS) and a poly(methoxy siloxane) (PMS) composite, were used to separate n-butanol and t-butanol from dilute aqueous mixtures. The effect of feed concentration on the flux and selectivity was investigated. Both membranes were found to be more permeable to n-butanol than t-butanol. The PDMS membrane was found to be more effective than the.
An assessment on the primary productivity of two fresh water aquaculture ponds at Guwahati with reference to physicochemical parameters

The variation of primary productivity in terms of NPP, GPP and CRV of water was studied at two fresh water aquaculture ponds named as Pond A, a manually managed pond (surface area 1.4 hac) with the application of lime and fertilizers and Pond B (surface area 0.5 hac), a natural pen culture pond recovered from a part of swamp located at Gauhati University Campus, Guwahati, Assam, India (latitude 26009/26// N and longitude 91040/21// E). In both the ponds comparatively high density of plankton were recorded in monsoon season of the study period with a luxuriant growth of Microcystis aeruginosa during late monsoon to early autumn in Pond A. The differences of water temperature between the two studied aquaculture ponds are not well marked, however, the water temperature of Pond B is always observed lower than that of the Pond A. The water of Pond A is found to be more alkaline than the Pond B. A normal range of fluctuation in DO, FCO2, TA and TH of water in both the ponds is maintained throughout the study period. During the investigations period, the experimental values of GPP, NPP, CRV show more or less a normal trend where GPP and NPP of the studied ponds indicates bimodal pattern of increase showing lower value in rainy monsoon season and higher during pre-monsoon summer months. The CRV of Pond A shows two prominent winter and autumn peaks followed by a lean period in summer and monsoon whereas in Pond B does not show prominent peak but exhibits the lowest profile in June of investigation period.
Locating minima on seams of intersecting potential energy surfaces. An application to transition structure modeling

It is proposed that the equivalent of a transition structure within a force field model can be defined as the lowest energy structure on the seam of the two intersecting potential energy surfaces valid for the reactant and product. The present paper describes a method for locating such minima and compares the obtained results with ab initio transition structures and with experimental activation energies for closely related systems. Using Allinger's MM2 force field, it is shown that the method generates transition structures with overall features close to those obtained by ab initio calculations, and Yends in activation energies are also reproduced reasonably well
Innovative oxy-coal combustion process suitable for future and more efficient zero emission power plants

The problem with CO{sub 2} capture from a flue gas stream is related to its low concentration, which makes the process of separation very energy-intensive, complex and, as a result, expensive. The CO{sub 2} separation process can be optimized by increasing the concentration of CO{sub 2} and reducing nitrogen concentration in the stream as it happens, in the oxy-fuel combustion process. In such a case, the oxidant flow is typically a mixture of oxygen, steam and carbon dioxide, with a very low concentration of nitrogen. Since the oxy-combustion process leads to very high temperatures, flue gases must be circulating through the chemical reactor to keep the combustion adiabatic temperature below acceptable values, due to the limits imposed by material resistance. This paper focuses on an innovative oxy-coal combustion process named ISOTHERM{reg_sign}, based on a flameless combustion technique which is mentioned in recent literature also as 'Mild' combustion. The combustion process takes place within a pressurized and refractory-lined furnace, approaching temperatures close to 2000 K. The process has been experienced at pressurized conditions up to 4 bar on a 5 MW pilot plant for thousands of hours. In this paper, starting from a detailed description of the process, results obtained by the preliminary experimental tests are presented and discussed. Then, a development and demonstration program to assess the suitability of this technology for zero emission power generation at large scale in one of the units of Brindisi power station is presented. 10 refs., 5 figs., 2 tabs.
Enhanced ultraviolet electroluminescence from p-Si∕n-ZnO nanorod array heterojunction

The authors report enhanced ultraviolet electroluminescence at room temperature from a diode structure consisting of vertically oriented ZnO nanorod arrays grown on a p-typed silicon substrate. Excitonic emitting peak at wavelength of 385nm with a full width at half maximum (FWHM) of 23nm and a defect-related visible emitting peak at the wavelength of 546nm with a FWHM of 124nm are observed from this structure under forward-bias voltage. The intensity ratio of the ultraviolet peak and the visible peak reaches 4.7. The scanning electron microscope, x-ray diffraction, energy dispersive x ray, I-V, and electroluminescence measurements demonstrate that good crystal structure and rectifying diodelike behavior are obtained and defect-related visible light emission is greatly restrained.
Determination of total metal pollutants in water with optical detection

The total concentration of heavy metal ions was measured with the use of a highly sensitive reagent (4-(2-pyridylzo)-resorcinol (PAR)). Because of PAR chelates are slightly soluble in water and their forming is not selective, the analytical procedure for Cd, Cu, Hg, Pb, Zn determination was developed to perform the analysis in an aqueous environment without the need of inconvenient and time-consuming extraction. A proposed analysis method is more useful in comparison with classical FIA analysis what is crucial during fast classification of various natural water samples. To minimize the chemicals consumption such a classification can be performed in a specially designed microsystem. The Y- shape microchannel structure with a mixing area was made by fine engraving in PMMA plate and sealed with the PDMS one. The M2+-PAR complex forming conditions were determined for each of the chosen metal ions. The solubility of formed complexes was better when a micellar environment was created by the addition of a non-ionic surfactant (Triton X100). Next the synthetic mixtures of Cd, Cu, Hg, Pb, Zn ions were prepared to obtain total molar metal ions concentration in the range from 10-6 to 10-4 M and measured after on-chip reaction. A tap water and HAC-sample (Highest Allowable Concentration, ΣMe=1,2•10-5 M) were also measured. The detection was performed in a special flow cuvette and spectra measurements were carried out using diode array spectrophotometer and CCD detector.
Effects of aluminum on the growth and element composition of 20 winter cultivars of Triticum aestivum L. (wheat) grown in solution culture

Abstract Seedlings of twenty cultivars of Triticum aestivum L. differing in tolerance to aluminum (Al) were grown with Al (74 uM, 2.0 mg L‐1 ) and without Al at pH 4.5 to examine the effect of Al on the element composition of leaf and root tissues of juvenile plants. Treatment with Al reduced concentrations of Mg and Mn and increased concentrations of Al, P, Ca, and Fe in roots. Treatment with Al reduced concentrations of P, Ca, Mg, Fe, and Mn in leaves. Concentrations of Mg, Fe, and Mn in leaves were in the range considered to be deficient. Cultivars differed in the effect of Al on element composition. Concentrations of Ca, Mg, Fe, and Mn in leaves of the 20 cultlvars grown with Al were positively correlated with cultivar tolerance to Al as measured by relative root yield. The variance, however, was relatively high. Leaf P concentrations of seedlings grown with Al were not significantly correlated with tolerance to Al. Differences among cultivars in the effect of Al on element, composition were not likel.
Influence of heat treatment on structure and some physical properties of lithium boro-niobate glass

The glass composition (90 mol% Li2B4O7–10 mol% Nb2O5) was prepared by the melt quenching technique. The quenched sample was heat treated at 480°C, 545°C and 630°C for 5 h and heat treated at 780°C with different time. The times were 5, 10, 15, 20, 28, and 36 h. The glass and glass ceramics were studied by differential thermal analysis (DTA), X-ray diffraction (XRD), and dc conductivity as a function of temperature. Lithium niobate (LiNbO3) and lithium diborate (Li2B4O7) were the main phases in glass ceramic addition to traces from LiNb3O8. Crystallite size of the main phases determined from the X-ray diffraction peaks are in the range <100 nm. The fraction of crystalline (LiNbO3) phase increases with increase the heat treatment temperature and time. The relation between physical properties and structure were studied.
Electrical characterization of a quartz crystal in high pressure CO2 by impedance analysis

The quartz crystal microbalance (QCM) is a very accurate sensor for measuring small changes of mass of thin films spread on the quartz surface. Under certain conditions, the resonance frequency of a quartz crystal can be used for monitoring the mass change caused by solvent adsorption or dissolution inside a film. However, when a quartz crystal is immersed in a high-pressure non-inert gas, various effects such as pressure, viscosity, roughness on the surface of the quartz crystal, adsorption of gas or even gas film formation slipping at the solid–gas interface can influence the resonance frequency of the quartz crystal and consequently complicate the relation between mass and frequency changes. In order to determine experimentally such effects in contact with carbon dioxide in the neighborhood of the critical conditions, the resonance curve of a quartz crystal under gas pressure was examined with a network analyzer which is able to determine both resonance frequency and half-band-half-width on several overtones.