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This work assesses six different agricultural residues with the aim of finding alternative raw materials for a soda semichemical pulping process: stems of bell and chili pepper ( Capsicum annuum ), broad bean ( Vicia faba ), asparagus ( Asparagus officinalis ), pea ( Pisum sativum ), and okra ( Abelmoschus esculentus ). Pulping yields higher than 60% (m/m) were obtained, except for pea stems (43%). The drainability of all the pulps, expressed as the Schopper-Riegler index (ºSR), had values of over 70 ºSR. The Kajaani analyses of the fibers showed acceptable fiber lengths in all cases (0.64–0.92 mm), but on average shorter than the lengths of pulps from a commercial fluting paper (Old corrugated Container, OCC), that was found to be 1.27 mm. Handsheets of paper were produced both with the pulps under study and with mixtures of these pulps with OCC pulp. Several properties were measured to assess the use of the new fibers in a paper for cardboard production. The property showing the greatest differences was the Gurley porosity, ranging from 25 mL/min (asparagus) to 1300 mL/min (broad bean). Of the six residues tested, the okra residue fiber showed better properties than the commercial paper fiber (Concora Medium Test indexes: 1.5 N m 2 /g and 1.1 N m 2 /g respectively, Burst Indexes: 2.3 kPa m 2 /g and 1.7 kPa m 2 /g, respectively), yielding similar mechanical properties to those of high quality fibers obtained from miscanthus ( Miscanthus giganteus ). Broad bean residue could also be a promising raw material, though its properties are not as good as okra’s. [ABSTRACT FROM AUTHOR]

The paper presents an effective plate formulation based on isogeometric analysis (IGA) and a novel simple quasi-3D hyperbolic shear deformation theory (S-Q3HSDT) to study static bending, free vibration, and buckling behaviors of functionally graded plates. In S-Q3HSDT fashion, five unknowns per node are included; both shear deformation and thickness-stretching effects across the thickness are taken into account; and the awkward shear locking phenomenon is avoided. The requirement for C 1 -continuity in terms of the S-Q3DHSDT is straightforwardly possessed with the aid of inherent high-order continuity of non-uniform rational B-spline (NURBS), which serve as basis functions in our IGA formulation. The superior performance and accuracy of the proposed method is demonstrated through numerous numerical examples. The calculated results are then compared with reference solutions, investigating the effects of boundary conditions, gradient index, and other aspect ratios on mechanical responses of functionally graded plates. [ABSTRACT FROM AUTHOR]

A challenge in developing microfluidic devices for fully portable and automated field analyses is the ability to integrate and store reagents in a stable form while maintaining a low cost for the system. Paper-based field-deployable devices are currently the most extensively explored platforms for field use; however, centrifugal devices offer a means for heightened device automation and portability. The basis for many field devices is chemical sensing via colorimetric reactions. Here, we describe the development of polyester-paper hybrid microfluidic devices using a fabrication method, compounded from the print, cut and laminate (PCL) technique, that allows for simple yet effective dry reagent storage for enhanced use with centrifugal or polymeric-based devices. We utilized various proof-of-principle colorimetric assays for multiple applications, including the analysis of total protein, serum albumin, cocaine, 2,4,6-trinitrotoluene (TNT) and iron content. Localized reagent integration facilitated by paper punches allowed for both reagent stability prior to reaction for storage, color stability post-reaction for image analysis, and was compatible for multi-step analyses. Qualitative and quantitative results were achieved with the broad range of sample applications trialed here, while still maintaining the ability for downstream processing. [ABSTRACT FROM AUTHOR]

Thin film microextraction (TFME), which is based on the retention of target analytes in a thin polymeric coating, is a powerful sample treatment technique with multiple applications. This article describes an easy and cheap procedure to synthesize polystyrene membranes which can be used as sorptive phases in TFME. The polymeric film is formed by the simple deposition of a thin polymeric layer over a conventional laboratory paper that acts as inert support. The synthesis has been studied and the resulting material has been characterized by infrared spectroscopy and scanning electron microscopy. The thin film has been analytically evaluated using the determination of methadone in urine samples by gas chromatography/mass spectrometry (GC/MS) as proof of concept problem. A pipette tip manifold, that allows the confinement of the film while permits the sample and solvents handling, has been designed for the extraction. The developed method provides a good linearity (R 2 = 0.9986) and sensitivity (limit of quantification of 10 μg/L), especially if the low sample volume (200 μL) used is considered. The precision (relative standard deviation better than 14%) and relative recovery values (average value of 106% for five independent samples) demonstrated the potential of the approach. [ABSTRACT FROM AUTHOR]

Knowledge of the actual shape of the point spread function (PSF) is of the utmost importance for paper and print quality assessment, since the PSF represents the degree of lateral scattering of light which is closely associated with the size of the optical dot gain. Importance of the correct shape of the PSF prompted us to propose a new experimental method for determining optical component of PSF of a paper substrate by studying the interaction of collimated light and paper and at the same time demonstrate superiority of the Lorentzian shaped PSF compared to the Gaussian, which is commonly used in the description of the PSF. Additionally, measured profile of the scattered light was compared with the profile obtained from Monte Carlo simulation for identical wavelength of incident light. Once the shape of the optical PSF was determined, FTIR spectra of samples were recorded and analysed, aiming to determine how the ratio of chemical and mechanical pulp influences the shape of the optical PSF. All results indicate better approximation of Lorentzian PSF compared to Gaussian, and imply correlation between the share of mechanical and chemical pulp in paper and characteristics of PSF. [ABSTRACT FROM AUTHOR]

Practical applications require scalable, low cost and facile approaches to fabricate coatings that are repellent to liquids and yet are resistant to mechanical impact and abrasion which may occur during service operation of these materials. Here we report fabrication of superhydrophobic (SHP) coatings on paper substrates by one-step spray-coating of fluorinated silica nanoparticles. The coatings were extremely repellent to water and organic liquids with surface tensions higher than ~ 45 mN/m, as demonstrated by the sliding angles that are lower than 5°. The coated paper substrates retained their liquid repellency behavior without any discernable change in their static contact and sliding angles following different mechanical wear tests. Mechanical robustness together with demonstrations in self-cleaning, anti-icing and food-packaging show great promise for the use of fabricated paper substrates in different applications. A significant finding of the present work is that the mechanical robustness of the spray-coated fluorinated silica nanoparticles in the absence of any polymeric matrix/binder was dramatically higher on paper in comparison to flat substrates. These results suggest that the inherent microstructure of the paper provides a suitable matrix for protecting the functionalized nanoparticles against external mechanical effects and present an effective strategy for improving the mechanical robustness of the coatings fabricated by one-step spray-coating of nanomaterials. [ABSTRACT FROM AUTHOR]

Starch-coated paper is widely used in packaging, printing, writing, and so on. However, achieving starch-coated paper with excellent moisture resistance remains a challenge for its end uses. To overcome this challenge, we hypothesize that the film-forming ability of starch plays a pivotal role in the moisture resistance of starch-coated paper. Polyvinyl alcohol (PVA) is used to enhance the film-forming capability of starch film and the moisture resistance of PVA/CS coated paper is evaluated in terms of moisture absorption, tensile index, and stiffness. A PVA/CS film with only a coating weight of 4.0 g/m 2 can fully cover the porous structure of paper that leads to a higher moisture resistance than CS-coated paper with a similar loading weight. However, as the coating weight continues to increase, the decline of the mechanical properties of PVA/CS coated paper is almost unchanged. Furthermore, the moisture resistance of PVA/CS coated paper (coating weight is larger than 4.0 g/m 2 ) is further improved by using glyoxal as moisture proof agent (MPA). Only 4.8% and 6.3% losses in the tensile index and stiffness at a coating weight of 4.0 g/m 2 are achieved before and after moisture treatment, respectively. These results may shed light on exploring new method to enhance moisture resistance of starch-coated paper. [ABSTRACT FROM AUTHOR]

Cotton wool, cotton textile, tissue paper and printing paper, all potential waste cellulosic materials, were directly converted to sorbitol using a Ru/CNT catalyst in the presence of H 2 and using only water as solvent, without any acids. Conversions up to 38% were attained for the raw substrates, with sorbitol yields below 10%. Ball-milling of the materials disrupted their crystallinity, allowing reaching 100% conversion of cotton wool, cotton textile and tissue paper after 4 h, with sorbitol yields around 50%. Mix-milling these materials with the catalyst greatly enhanced their conversion rate, and the materials were efficiently converted to sorbitol with a yield around 50% in 2 h. However, ball- and mix-milled printing paper presented a conversion of only 50% after 5 h, with sorbitol yields of 7%. Amounts of sorbitol of 0.525, 0.511 and 0.559 g could be obtained from 1 g of cotton wool, cotton textile and tissue paper, respectively. [ABSTRACT FROM AUTHOR]

This work demonstrates a paper-based microfluidic sampling and separation platform that allows potentiometric sensing of chloride ions in presence of strongly interfering salicylate ions using a solid-contact ion-selective electrode as a detector. The device was composed of two pieces of paper with different shapes and pore sizes. A “T” shaped filter paper with a pore size of 12–25 μm was used as the detection zone. A filter paper with a pore size of 2.0 μm was modified with a complexing agent (Fe 3+ ) and served as the separation zone. The two pieces of the paper were joined together just like a jigsaw. A solid-contact Cl − −selective electrode and a reference electrode were gently pressed onto the detection zone to create a direct contact between the electrodes and the solution absorbed in the paper. Utilizing the possibility to form stable complexes between Fe 3+ and salicylate, the proposed platform enables the separation of salicylate and detection of chloride. This system offers a convenient platform for both sampling and separation of ions, in which sample pretreatment procedures can be simplified or avoided. [ABSTRACT FROM AUTHOR]

This paper presents a multi-scale approach to predict the effective hygro-mechanical behaviour of paper sheets based on the properties of the underlying fibrous network. Despite the vast amount of literature on paper hygro-expansion, the functional dependence of the effective material properties on the micro-structural features remains yet unclear. In this work, a micro-structural model of the paper fibrous network is first developed by random deposition of the fibres within a planar region according to an orientation probability density function. Asymptotic homogenization is used to determine its effective properties numerically. Alternatively, two much more idealized micro-structural models are considered, one based on a periodic lattice structure with a regular network of perpendicular fibres and one based on the Voigt average. Despite their simplicity, they reproduce representative micro-structural features, such as the orientation anisotropy and network level hygro-elastic properties. These alternative models can be solved analytically, providing closed-form expressions that explicitly reveal the influence of the individual micro-scale parameters on the effective hygro-mechanical response. The trend predicted by the random network model is captured reasonably well by the two idealized models. The resulting hygro-mechanical properties are finally compared with experimental data reported in the literature, revealing an adequate quantitative agreement. [ABSTRACT FROM AUTHOR]

A deacidifying/antifungal mixture composed of calcium propionate, methylparaben and propylparaben was tested against Aspergillus niger , Cladosporium cladosporioides , Chaetomium globosum , Penicillium chrysogenum and Penicillium corylophilum . The preventive treatment of paper samples resulted in a complete fungal growth inhibition on 4 of the 5 tested species. The antifungal properties of the formulation remained unaffected for a minimum period of one year. The disinfecting treatment with the mixture led to a total elimination of all tested fungal species. The effects of the tested formulation on paper were evaluated in terms of pH, colourimetry, folding endurance, FTIR and XRD, using moist heat artificial ageing. Aside from plain paper, paper previously colonized by A. niger was tested to evaluate the potential of the formulation in preventing deterioration caused by fungal metabolites. In plain paper, an effective deacidification and long-term prevention of mechanical resistance loss were achieved, although a slight paper discoloration occurred. On previously colonized by fungi, the treatment effectively prevented the deterioration caused by fungal metabolites. [ABSTRACT FROM AUTHOR]

Monodisperse aqueous upconverting nanoparticles (UCNPs) were covalently immobilized on aldehyde modified cellulose paper via reductive amination to evaluate the multiplexing capacity of luminescence resonance energy transfer (LRET) between UCNPs and quantum dots (QDs). This is the first account of a multiplexed bioassay strategy that demonstrates the principle of use of a single form of UCNP as donor and three different color emitting QDs as acceptors to concurrently determine three analytes. Broad absorbance profiles of green, orange and red QDs that spanned from the first exciton absorption peak to the UV region were in overlap with a blue emission band from UCNPs composed of NaYF 4 that was doped with 30% Yb 3+ , 0.5% Tm 3+ , allowing for LRET that was stimulated using 980 nm near-infrared radiation. The characteristic narrow and well-defined emission peaks of UCNPs and QDs allowed for the collection of luminescence from each nanoparticle using a band-pass optical filter and an epi-fluorescence microscope. The LRET system was used for the concurrent detection of uidA, Stx1A and tetA gene fragments with selectivity even in serum samples, and reached limits of detection of 26 fmol, 56 fmol and 76 fmol, respectively. [ABSTRACT FROM AUTHOR]

The possibility of using pyrolyzed paper as disposable working electrodes for trace metals determination is reported for the first time. A small piece of pyrolyzed paper (0.7×0.7 cm) was positioned at the bottom side of the electrochemical cell using a rubber O-ring, which defined the electrode area (0.48 cm; 0.18 cm 2 ). A large number of electrodes can be obtained from a single piece of standard dimensions (2.5 cm×7.5 cm) of paper, therefore minimizing the cost per unit. The electrochemical performance of the pyrolyzed paper was demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy and by the determination of Zn, Cd, and Pb by square-wave anodic stripping voltammetry. The unmodified pyrolyzed paper showed excellent performance for Pb and Cd detection (LOD =0.19 and 0.16 ppb, respectively). In the presence of Bi 3+ (in-situ film formation), the simultaneous determination of Zn, Cd and Pb was also possible (LOD=0.26, 0.25, and 0.39 ppb, respectively). [ABSTRACT FROM AUTHOR]

A new sensitive non-invasive gold nanoparticle-based sensor that enables to detect thiols in the human skin has been developed. The detection procedure implied the assessment of the color change of a paper sensor resulting from aggregation of gold nanoparticles caused by thiols. The ratio of the intensity of the photo image blue channel vs the red one (in units of RGB coloration) served as analytical response. The main thiol in the skin is glutathione, therefore, it was used as model biothiol and spiking substance. The range of linearity for glutathione was 8–75 µM, the detection limit was 6.9 µM. RSD≤7% is for inter-day determination of 10 μM glutathione and RSD≤12% is the intra-day value. The recovery of 5 µM and 10 µM of glutathione was evaluated by applying solution, containing thiol-spikes, on skin. The results varied in the range 77–138%. A hundred-fold excess of serine, alanine, histidine, threonine, creatinine, urea, and ammonia; a ten-fold excess of glycine, proline, leucine, isoleucine, phenylalanine, asparagine; and a five-fold excess of valine, tryptophan, tyrosine, and uric acid, which can be extracted from the skin and is contained in the test matrix, have no significant effect on 10 µM glutathione signal. Thiols level in the skin of volunteers (21–65 years old, men and women) detected with the use of a proposed non-invasive sensor was 11.6–47.5 µM. [ABSTRACT FROM AUTHOR]

The present paper explores the short span compression tester (SCT) as a means to experimentally determine the transverse shear moduli of paper. These moduli, which are known to be difficult to determine by any other means, are of importance for the behavior of paper during tissue manufacturing and in the converting and embossing of paperboard. Testing was conducted on paper of two different grammages both in MD and in CD. By applying the Timoshenko–Engesser theory for buckling of shear compliant materials, estimates of the transverse shear moduli were obtained through the measured SCT values and standard measurements of the Young’s modulus and the thickness. These estimates were evaluated by detailed FE-analyses of the SCT setup incorporating initial geometrical imperfections representative for real test conditions. It was found that the Timoshenko–Engesser theory gives estimates of the transverse shear moduli that are within an accuracy well applicable for most engineering purposes. The results suggest that the method is at least as accurate as any other, more involved, method that could be used for the purpose. [ABSTRACT FROM AUTHOR]

The research aim was to determine the effectiveness of disinfection methods: thyme essential oil microatmosphere (TEO), silver nanoparticles misting (AgNPs), and low temperature plasma (LTP) by culture-dependent method and RNA analysis. In addition, we examined the influence of disinfection on mechanical and optical properties of paper from historical books with different levels of microbial contamination. All disinfection methods were generally bacteriostatic and fungistatic. The AgNPs misting method was more effective for bacterial inhibition ( R = 60–100%), than LTP ( R = 25–100%) and TEO ( R = 12–100%); all tested methods were less effective for fungi ( R = 0–99.8%). TEO exhibits a broader spectrum of fungicidal activity compared to AgNPs and LTP. The antimicrobial effectiveness depended on the area from where the microorganisms were isolated and their sensitivity to the active agent. A higher disinfection effectiveness was observed for books with higher levels of microbial contamination. RNA concentration was a good marker of antimicrobial activity of disinfection. RNA amount decreased by 95–100% after disinfection with LTP and TEO, and by 29–89% after AgNPs disinfection. Disinfection of paper from historical books with LTP, AgNPs and TEO did not significantly influence or have a positive effect on the mechanical and optical properties of paper from tested historical books. We show that LTP, TEO, and AgNPs can be used as microbiostatics, alternatively to the currently available methods. [ABSTRACT FROM AUTHOR]

Clotrimazole is a well-known antimycotic agent, listed in the World Health Organization List of essential medicines, with minimal health side effects acknowledged throughout a long certification period. In this study, clotrimazole in isopropanol was tested as a potential antifungal treatment for paper objects. The antifungal properties of this azole compound were evaluated against five of the most common fungal species affecting paper collections. The addition of a deacidifying agent, calcium hydroxide nanoparticles, resulted in a multipurpose formulation also aimed at neutralizing the deleterious effects of acids excreted by fungi. Clotrimazole showed antifungal activity against all tested fungal species and its effectiveness followed the ascending order: Chaetomium globosum < Cladosporium cladosporioides < Penicillium chrysogenum < Aspergillus niger < Penicillium corylophilum . The best relationship between minimal concentration and fungal inhibition was achieved for 0.05% clotrimazole. The impact of the tested formulation on paper preservation was evaluated in terms of pH, colour and folding endurance, using moist heat artificial ageing. Clotrimazole and calcium hydroxide nanoparticles protected the paper from acidification and loss of folding endurance in the long term, thus representing a non-aqueous alternative treatment for paper affected by fungi. [ABSTRACT FROM AUTHOR]

Volumes from an archive of the University of Milan showed whitish-grey discolouration putatively caused by microorganisms. Microscopic and viability assays proved that discolouration from two volumes were characterized by a marked presence of viable fungi, demonstrating that they were mainly biological in nature. Fungal sequences were phylogenetically most closely related to Eurotium , Aspergillus , Candida , Penicillium , Alternaria , Phaeosphaeria , Capnodiales and Pleosporales taxa. SEM analysis showed that Eurotium halophilicum is dominant on the two infected volumes. Viable airborne fungal loads near the two volumes were higher than recommended maximum values, demonstrating that airborne fungi could represent a source of risk. The airborne microbial community sampled in two different seasons was composed by fungi belonging in the genera Aspergillus , Candida and Eurotium . The detection of E. halophilicum also in the archival air indicated a possible source of contamination. Fluctuations of thermo-hygrometric values were also observed in the archive in the different seasons. The occurrence of white efflorescence on the stored volumes most likely depended on the lack of both a dusting programme and air-conditioning, and insufficient ventilation in the repository, and, on the hygroscopic behaviour of the binding materials used in the manufacture of the volumes. [ABSTRACT FROM AUTHOR]

We report on top-gate organic field-effect transistors (OFETs) fabricated on specialty paper, PowerCoat™ HD 230 from Arjowiggins Creative Papers coated with a buffer layer composed of a polyvinyl alcohol (PVA) and polyvinylpyrrolidine (PVP) blend. OFETs operate at low voltages and display average carrier mobility values of 1.7 ± 1.1 × 10 −1 cm 2 /Vs, average threshold voltage values of −1.4 ± 0.2 V, and average on/off current ratio of 10 5 . OFETs also display excellent operational stability demonstrated by stable 1000 scans of the transfer characteristics and by stable on-currents displaying less than 6% change during a DC bias stress test at V DS = V GS = −10 V for 1 h. Furthermore, OFETs on paper display a decrease of only 7% in their on-state current during a bending test. The performance of these OFETs on paper is comparable to that displayed by top-gate OFETs with the same geometry fabricated on glass substrates. [ABSTRACT FROM AUTHOR]

The mechanical response of three different structural core sandwich panels in out-of-plane compression and shear has been analyzed. Specific core shapes examined are arc-tangent, wavy trapezoidal and hemispherical. Unit cells consisting of representative elements of the core attached to face sheets were selected for analysis. Both face sheets and core were assumed made from paper. Finite element analysis employing large deformation and rotations and orthotropic elastic–plastic behavior was used. The results show that the arc-tangent and trapezoidal cores are prone to collapse by extensive bending and buckling, whereas the hemispherical core behaved more stably in compression and shear. Core sheets with a hemispherical shape were prepared from copy paper sheets in a specially designed forming machine. Sandwich test specimens were prepared from this core and tested in out-of-plane compression, and the load-displacement response was compared to predictions from finite element simulations. The experimental and finite element results were consistent. [ABSTRACT FROM AUTHOR]

Fourier transform Raman spectroscopy and (dispersive) confocal Raman microscopy have been applied to quantitatively and qualitatively describe the local distribution of chemical moieties of poly(styrene- co -maleimide) coatings on paper substrates containing different amount of imide. In parallel, local coating defects have been imaged for a better understanding of the influence of the coating composition on homogeneity at macro- to microscale levels. From FT-Raman spectroscopy, the imide content was calculated in quantitative agreement with previous thermoanalytical data. From dispersive spectroscopy, the measuring parameters were optimized for single-point measurements including signals of the coating and macropoint measurements including more intense signals of the paper. The large surface maps (5 × 5 mm 2 ) provided good quantification for the lateral distribution of imide moieties and coverage for coatings with different thickness and imide content, based on relative intensities of imide/styrene and imide/cellulose bands. The inhomogeneities were related to the formation of surface patterns for coatings with high viscosity and presence of non-imidized residues. From detailed surface maps (1 × 1 mm 2 ), sensitive Raman bands were selected to describe variations in imide and styrene concentrations, conformations and interactions with fillers and cellulose. Based on data from Raman analysis, interactions between nanoparticles and cellulose possibly happened through hydrogen bonding. [ABSTRACT FROM AUTHOR]

Paper has been an essential material in our daily life since ancient times. Its affordability, accessibility, adaptability, workability and its easiness of usage makes it an attractive structural material to develop many kind of technologies such as flexible electronics, and energy storage and harvesting devices. Additionally, the scientific community has increased its interest on waste heat as an environmentally friendly energy source to support the increasing energy demand. Therefore, in this paper we described two affordable and flexible thermoelectric nanogenerators (TEGs) developed on paper substrates by the usage of simple micromachining and microfabrication techniques. Moreover, they exhibit mechanical stability and adaptability (through folding and cutting techniques) for a diverse set of scenarios where vertical or horizontal schemes can be conveniently used depending on the final application. The first TEG device, implemented on standard paper, generated a power of 0.5 nW (ΔT=50 K). By changing the substrate to a tearless and extra-smooth polyester paper, the TEG performance was optimized achieving less internal resistance and a greater power of ~80 nW (ΔT=75 K), at the cost of more rigidity in the substrate. This power represented over three times higher power production than the standard paper–based TEG with same dimensions, number of thermoelectric pairs and temperature difference. Another interesting aspect of paper based TEG is due to its foldability, one can control the temperature difference by unfolding (larger separation between hot and cold ends) and folding (smaller separation). Finally, one of the underlying objectives of this work is to spread the availability of essential technologies to the broad population by inclusion of everyday materials and simple processes. [ABSTRACT FROM AUTHOR]

The effectiveness of ionizing radiations for the preservation of cultural heritage (CH) has been recently demonstrated. Although these processes present many advantages with respect to the traditional methods, physico-chemical modifications induced by radiation (namely side effects) represent a concern for CH restorers, archivists and librarians. The present work is focused on the study of the effect of gamma irradiation parameters on the main features of paper. In particular, total absorbed doses up to 10 kGy (commonly suggested for preservation treatments) have been applied, with dose rates ranging from 3 to 10 kGy/h. Different experimental techniques (FTIR, EPR, viscosity and colorimetric analysis) have been used to study the side effects occurrence. The results indicate that the fine-tuning of irradiation condition allow to minimize the unwanted changes, induced by radiation in the treated paper samples. • Gamma radiation at absorbed doses common for preservation of cultural heritage (up to 10 kGy). • Side effects evaluation with several experimental techniques (FTIR, EPR, DP, colorimetric analysis). • Studies were performed at different dose rate values. • Irradiation parameters optimization to minimize the side effects. • Gamma rays represent a suitable and reliable tool for bio-deteriogens elimination purpose. [ABSTRACT FROM AUTHOR]

The demand for rapid diagnostic in developing countries has recently increased, in part due to growing populations, emerging diseases, and rise in healthcare cost. Use of low-cost lateral flow/dipstick devices, especially paper-based ones, has increased. In most of the developing world, however, biomedical waste management systems either do not exist or are poor, as such, used devices either get incinerated or dumped alongside household trash. The plastic casing that is often used to hold the test strip, while useful before the test, also slows the biodegradation of the used contaminated devices. We demonstrate that by replacing the plastic casing with paper encasements, we promote biodegradation of these devices while reducing its total weight, making their transport and packaging more compact and more environmentally friendly—hence qualifying this simple modification as green engineering. The ability to use paper casing has the added advantage that devices can be readily assembled locally with ease and without need for sophisticated manufacturing tools as needed with the plastic casings. [ABSTRACT FROM AUTHOR]

A piezoelectric based touch sensitive device has been successfully fabricated by screen printing silver (Ag) and polyvinylidene fluoride (PVDF) inks as conductive and piezoelectric materials, respectively, on paper substrate. X-ray diffraction (XRD) analysis was performed to verify the formation of β-phase crystals in the PVDF layer during the curing process. Voltages, as high as 0.22 V, were observed for human finger touch tests and a sensitivity of 0.3 V/N was obtained when varying forces ranging from 0.2 N to 1.4 N, in steps of 0.2 N, were applied on the printed device. The piezoelectric-voltage analysis demonstrated that the printed device can be used for both touch and force sensing applications. [ABSTRACT FROM AUTHOR]

Commercial inkjet-printers from manufacturers like Epson or Brother can be used for rapid prototype printing conductive traces onto paper or flexible PET substrates by using nanoparticle based dispersions. The surface coating of the substrate influences the attainable electrical conductivity and dielectric permittivity as well as the loss tangent, which are important parameters for developing inkjet-printed microwave circuits on paper substrates. For characterizing the permittivity conventional methods are using microstrip ring or microstrip transmission line resonators that require the printing of two electrically conductive layers. In the proposed paper, a novel method is introduced to determine the relative permittivity and loss tangent via a coplanar waveguide resonator realized on a single layer. [ABSTRACT FROM AUTHOR]

This paper reports on a study evaluating the value of a documentary as a key medium to communicate design research. We present information from the evaluation of a second screen application using video as well as a scientific paper, in order to assess how the efficacy and usefulness of using such a documentary for science communication is perceived when compared to a scientific paper. Techniques of a method called Design Documentary , developed to inspire design research teams through video, combined with science journalism were the basis of the production. Twelve researchers and students were shown the documentary and asked to read the paper in counter-balanced order. Our qualitative results show that the documentary as a complementary means of communication can bring benefits to research communication, since it delivers information the paper cannot provide. However, the fact the video is not suited for peer review might restrict its place when compared to the paper. On the overall, participants thought both formats are valuable and are complementary. [ABSTRACT FROM AUTHOR]

During the last two decades, cellulose nanofibres (CNF) have emerged as a promising, sustainable reinforcement with outstanding potential in material sciences. Though application of CNF in papermaking is recent, it is expected to find implementation in the near future to give a broader commercial market to this type of cellulose. The present review highlights recent progress in the field of the application of cellulose nanofibres as additives in papermaking. The effect of CNF addition on the wet end process is analysed according to the type of pulp used for papermaking. According to the literature consulted, improvement in paper’s overall properties after CNF addition depended not only on the type and amount of CNF applied, but also in the pulp’s origin and treatment. Bulk and surface application of CNF also presented significant differences regarding paper’s final properties. This review also revises the mechanisms behind CNF reinforcing effect on paper and the effect of chemically modified CNF as additives. [ABSTRACT FROM AUTHOR]

Buckypaper (BP) is a planar film that consists of random network of multiwall carbon nanotubes (MWCNTs) held together by weak van der Waals interactions at tube-tube junctions. Although individual carbon nanotubes (CNTs) possess remarkable electrical properties, the electrical resistance of pristine BP is usually too high for practical applications. However, the electrical resistivity of BP can be attenuated by applying modest compressive stresses. Herein, we report an analytical model for predicting the electrical resistivity of BP under defined level of compressive strain. The predictive piezoresistive model of BP was developed by formulating a direct relationship with the structural parameters, physical and electrical properties of CNTs. The basis of the piezoresistive model relied upon the geometrical probability approach in combination with classical Hertzian contact mechanics and constriction resistance techniques. A comparison has been made between the theoretical and experimental results of electrical resistivity of BPs with varying densities. A reasonably good quantitative agreement was obtained between the theory and experiments. The main source of error was caused by the uncertainty in the measurement of the initial BP thickness. Through theoretical modeling, the initial volume fraction of CNTs was found to be one of the key parameters that modulated the piezoresistive behavior of BP. [ABSTRACT FROM AUTHOR]

Laminated paperboard and paper is widely used in packaging products. It generally exhibits highly anisotropic and nonlinear mechanical behavior. The aim of this study is to describe the in-plane material behavior with an orthotropic elastic-plastic model based on the observed experimental behavior. A structural tensor-based approach was applied to model the elastic deformation, while a multi-surface based yield criterion was adopted to describe the yield behavior. The model incorporated nonlinear kinematic and isotropic hardening to capture the anisotropic hardening effect. In the experiment, the compressive yield stress was found to be insensitive to the previous tensile deformation. The proposed model could capture this compression yield stress preserving effect under reverse loading, which in turn reduced the required material parameters as expected. With the material parameters calibrated from a set of simple uniaxial tests in various directions, the model was shown to predict the stress-strain behavior for other orientations satisfactorily. The model was further validated with experiments under complex loading conditions and found to capture the highly anisotropic, elastic-plastic behavior accurately. [ABSTRACT FROM AUTHOR]

Herein, we have developed a simple, sensitive and paper-based colorimetric sensor for the selective detection of Chromium (Ⅵ) ions (Cr (VI)). Silanization-titanium dioxide modified filter paper (STCP) was used to trap bovine serum albumin capped gold nanoparticles (BSA-Au NPs), leading to the fabrication of BSA-Au NPs decorated membrane (BSA-Au NPs/STCP). The BSA-Au NPs/STCP operated on the principle that BSA-Au NPs anchored on the STCP were gradually etched by Cr (VI) as the leaching process of gold in the presence of hydrobromic acid (HBr) and hence induced a visible color change. Under optimum conditions, the paper-based colorimetric sensor showed clear color change after reaction with Cr (VI) as well as with favorable selectivity to a variety of possible interfering counterparts. The amount-dependent colorimetric response was linearly correlated with the Cr (VI) concentrations ranging from 0.5 µM to 50.0 µM with a detection limit down to 280 nM. Moreover, the developed cost-effective colorimetric sensor has been successfully applied to real environmental samples which demonstrated the potential for field applications. [ABSTRACT FROM AUTHOR]

Here we report a new conductivity sensing mechanism using a closed bipolar electrode (BPE) system for the first time. Briefly, the voltage dropping across the ECL reporting cell will change with the sample conductivity of the analytes cell in a closed bipolar system. Thus, a quantitative relation between the electrochemiluminescence (ECL) response and the sample conductivity is established. Based on this principle, chemicals those are not electroactive materials and do not participate in the ECL process can be detected now, which greatly expands the application range of the BPE and the powerful ECL technique. Then a paper-based bipolar ECL conductivity sensing platform was constructed and carefully characterized, and the results proved the rationality of this newly-proposed bipolar conductivity sensing mechanism. More importantly, this design is also a universal sensing platform, suitable for all the electrolytes without electroactivity (newly proposed), electroactive chemicals and chemicals directly related to the ECL reaction. [ABSTRACT FROM AUTHOR]

To optimize the pulping and refining processes of new alternative raw materials for papermaking, researchers generally perform tests that consume considerable time and large amounts of sample. We propose measuring the morphological properties of pulps from orange tree trimmings by image analysis systems, which are fast and user-friendly, to develop models relating key mechanical properties to the dimensions, the deformation and the population of fibers. Data modeling involves multiple linear regression, as used in other studies, and support vector regression, not used before for this purpose, achieving higher R 2 values (up to 0.90). Although tensile, tear and burst tests are still required to obtain accurate values, a quick morphological characterization allows for a rough but satisfactory prediction of paper strength. In this case, chemical pulping and moderate refining are shown to be necessary to obtain pulps of acceptable quality from orange tree trimmings. [ABSTRACT FROM AUTHOR]

Point-of-care (POC) diagnostics play an important role in delivering healthcare, particularly for clinical management and disease surveillance in both developed and developing countries. Currently, the majority of POC diagnostics utilize paper substrates owing to affordability, disposability, and mass production capability. Recently, flexible polymer substrates have been investigated due to their enhanced physicochemical properties, potential to be integrated into wearable devices with wireless communications for personalized health monitoring, and ability to be customized for POC diagnostics. Here, we focus on the latest advances in developing flexible substrate-based diagnostic devices, including paper and polymers, and their clinical applications. [ABSTRACT FROM AUTHOR]

In this paper an original and exhaustive mathematical modelling of air impingement drying systems for the production of tissue paper in the Yankee-hoods configurations is reported, which offers the possibility to optimize its energy performance. The model takes into account many detailed operative parameters of the overall drying process with the aim to execute its energy and mass balance and to evaluate its energy performances. The validity of the mathematical model has been assessed by comparison with actual data from an existing tissue paper mill. Finally, the energy performances of two different layouts of the air system have been evaluated and compared. Changing the operative parameters of the drying process, such as air jet temperature and speed and moisture content of the extraction air, it is possible to obtain the same paper production with an energy saving of about 4.5%. In average, the layout with two parallel air circuits assure an energy saving of about 1% with respect to the layout with a single air circuit. [ABSTRACT FROM AUTHOR]

For casework applications, understanding the source processes used to create a material and the effects of those sources on the results obtained by Isotope Ratio Mass Spectrometry (IRMS) of a bulk material is important. Likewise, understanding the effect of environment, home/office printing processes and some forensic testing in at least a basic context, ensures that in casework, enough information on the effects of these variables is available during comparison and interpretation. In this study, which focuses on oxygen isotopic abundance measurements, both fractionation and mixing effects were observed within the pulping and production process. Also observed in the carbon isotopic experiments, sampling that included toner changed the measured isotopic abundance values of the paper and should be avoided in casework. Inkjet printing processes were not shown to have an effect on the paper oxygen abundance values. Samples that were treated for fingerprints using 1,2-Indandione-Zn prior to sampling showed the greatest risk for misinterpretation of whether two samples had originated from the same source. While this study provides a good basis and understanding of the effects of a range of factors on document paper oxygen isotope values, further testing for a range of specific casework scenarios is required and should be undertaken on a case by case basis as the need arises. [ABSTRACT FROM AUTHOR]

Rice straw pulps produced under different conditions were subject to near infrared (NIR) spectroscopy. At the same time, samples from those pulps were used to make handsheets, whose mechanical properties were measured. These values and those of brightness were successfully fitted to the pulping variables. Relating them to the NIR spectra, we found valid correlations for all parameters except the burst index, concluding that NIR spectroscopy could be used as an economical, timesaving and non-intrusive way to predict the mechanical strength of pulps before the paper sheet is made. [ABSTRACT FROM AUTHOR]

Immobilized silver nano-particles (Ag NPs) possess excellent antimicrobial properties due to their unique surface characteristics. In this paper, immobilized silver nano-particles were synthesized in the presence of chitin nano-crystals (CNC) based on the Tollens mechanism (reduction of silver ion by aldehydes in the chitosan oligosaccharides (COS)) under microwave-assisted conditions. The prepared Ag NPs-loaded CNC nano-composites were then applied onto the paper surface via coating for the preparation of antibacterial paper. Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) results confirmed that the Ag NPs were immobilized onto the CNC. The transmission electron microscope (TEM) and scanning electron microscopy (SEM) results further revealed that the spherical Ag NPs (5–12 nm) were well dispersed on the surface of CNC. The coated paper made from the Ag NPs-loaded CNC nano-composites exhibited a high effectiveness of the antibacterial activity against E. coli or S. aureus . [ABSTRACT FROM AUTHOR]

Natural fibers are gaining much interest in composite materials because of their potential to replace conventional glass fibers. In particular, unidirectional flax fiber composites have shown excellent mechanical properties with different thermoset matrices. However, few data are available when they are made with a biodegradable thermoplastic matrix. This paper compares the mechanical properties of two types of unidirectional flax composites using polylactic acid as the matrix: one made with layers of aligned flax rovings alone and the other containing an additional paper layer fabricated using paper making techniques. The results show that specific tensile properties of the flax/PLA (252 MPa·cm 3 ·g −1 ) and flax-paper/PLA (217 MPa·cm 3 ·g −1 ) composites are similar to those made using woven glass fabrics impregnated with epoxy (227–278 MPa·cm 3 ·g −1 ). Very high impact strength (600 J/m) was also obtained for UD flax-paper composites compared to unreinforced resin (15 J/m). Together these mechanical properties are promising for industrial applications of this new reinforcement. [ABSTRACT FROM AUTHOR]

A new concept for fluid flow manipulation in microfluidic paper-based analytical devices (μPADs) is presented by introducing ionogel materials as passive pumps. μPADs were fabricated using a new double side contact stamping process and ionogels were precisely photopolymerised at the inlet of the μPADs. The ionogels remain mainly on the surface of the paper and get absorbed in the superficial paper-fibers allowing for the liquid to flow from the ionogel into the paper easily. As a proof of concept the fluid flow and mixing behaviour of two different ionogels μPADs were compared with the non-treated μPADs. It was demonstrated that both ionogels highly affect the fluid flow by delaying the flow due to their different physical and chemical properties and water holding capacities. [ABSTRACT FROM AUTHOR]

Mechanical-biological treatment plants treat municipal solid waste to recover recyclable materials, nutrients and energy. Waste paper and cardboard (WP), the second main compound in municipal solid waste (∼30% in weight basis), is typically used for biogas generation. However, its recovery is gaining attention as it can be used to produce add-value products like bioethanol and residual derived fuel. Nevertheless, WP suppression or replacement will impact anaerobic digestion in terms of biogas production, process stability and digestate management. Two lab-scale reactors were used to assess the impact of WP in anaerobic digestion performance. A control reactor was only fed with biowaste (BioW), while a second reactor was fed with two different mixtures of BioW and WP, i.e. 85/15% and 70/30% (weight basis). Results indicate that either replacing half of the WP by BioW or removing half of the WP has little impact on the methane production. When removing half of the WP, methane production could be sustained by a larger waste biodegradability. The replacement of all WP by BioW increased the reactor methane production (∼37%), while removing all WP would have reduced the methane production about 15%. Finally, replacing WP loading rate by BioW led to a system less tolerant to instability periods and with poorer digestate quality. [ABSTRACT FROM AUTHOR]

The effect of silica loading on the static frictional coefficient of nitrile rubber when paired with different types of papers is investigated. The influence of silica loading on the mechanical properties of nitrile rubber and its changes due to natural ageing is also examined. The objective of the study is to generate data for assessing the suitability of NBR as a lining material for impactive grippers. It is observed that the properties of NBR including frictional coefficient can be modified by varying the amount of silica. The static co-efficient of friction with most of the papers is highest at around 55 phr of silica. The properties like hardness, tear strength and resistance to oil increase with the amount of silica content while swelling index decrease with silica loading and the abrasion index peaks around 55 phr. The change in the mechanical properties due to natural ageing varies, though marginally. [ABSTRACT FROM AUTHOR]

The sustainable, efficient use of renewable bio-based additives in the production of various materials fits well into the concept of sustainability. Here, the concept of coaggregation of mineral filler particles and starch granules for improving filler-fiber interaction in paper-based cellulosic networks is presented. Coaggregation of precipitated calcium carbonate filler particles and uncooked, unmodified corn starch granules by cationic polyacrylamide (a cationic high molecular weight polymer flocculant) in combination with bentonite (an anionic microparticle) prior to addition to cellulosic fiber slurry delivered enhanced filler bondability with cellulosic fibers. For instance, under the conditions studied, preaggregation resulted in an increase in filler bondability factor from 9.24 to 15.21 at starch dosage of 1% (on the basis of the dry weight of papermaking stock). The swelling and gelatinization of the starch granules in starch-filler preaggregates or hybrids enabled the “bridging” of the gaps in cellulosic networks, leading to structural consolidation and strength enhancement. [ABSTRACT FROM AUTHOR]

The identification of forged and genuine historical banknotes is an important problem for private collectors and researchers responsible for the care of numismatic collections. This paper presents a research approach for detecting material differences in historical banknotes through the use of microfading spectrometry along with other techniques such as hyperspectral image analysis, Fourier-transform infrared spectroscopy, and X-ray fluorescence spectrometry. Microfading spectrometry results showed higher sensitivity to light irradiation for an overprint ink used on a suspicious banknote relative to its counterparts. In addition, the spectrocolorimetric changes experienced by the paper substrates during microfade testing also provided a way for discriminating between two groups of banknotes. These variations have been confirmed after analyzing the spectral and physico-chemical data obtained using the abovementioned complementary techniques. [ABSTRACT FROM AUTHOR]

Aims: Present-day screening of the diabetic foot involves the Semmes Weinstein Monofilament Test for evaluating loss of sensibility, while testing for intrinsic muscle weakness is not implied. Just as with the early detection of sensibility loss, early detection of intrinsic muscle weakness might have important implications for the prevention of both ulceration and deformity in patients with diabetes. The purpose of this study is to investigate the prevalence of patients with diabetes presenting intrinsic muscle weakness of the hallux, but with a normal sensibility of the sole of the foot.Methods: A cross-sectional study design was applied. Intrinsic muscle function of the hallux was measured with the Paper Grip Test, while sensibility of the sole of the foot was measured with the Semmes Weinstein Monofilament Test 5.07/10-g.Results: In a period of three months a total of 266 patients with diabetes (mean age 60, 134 females (50%), 177 type 2 diabetes mellitus (67%)) met the inclusion criteria and were examined for both intrinsic muscle weakness of the hallux and sensibility of the soles of the feet. The results showed that intrinsic muscle weakness was present more frequent in patients with impaired sensibility (P=0.001), also 20% of the population had intrinsic muscle weakness in the presence of normal sensibility. Multivariate regression analysis showed that only age is associated with patients with diabetes presenting normal sensibility but impaired intrinsic muscle function (P=0.017).Conclusions: The Paper Grip Test could have added value to current physical examination of the feet in patients with diabetes. [ABSTRACT FROM AUTHOR]

The probabilistic ecological risk assessment using terrestrial toxicity data has been mainly based on microfauna or mesofauna. Soil algae, which are food source for microfauna and mesofauna, may be alternatively used for assessing soil toxicity. However, there are no internationally recommended guidelines for soil algal bioassays, and the collection of algae from the test soils has some limitations. In this study, we suggested the paper-disc method as an easy-to-use alternative. This method has been widely used for testing the antibacterial toxicity of various chemicals in agar media by measuring the diameter of the inhibition zone around the disc. We adapted the paper-disc method for screening the toxicity of copper (Cu) and nickel (Ni) to the soil alga Chlorococcum infusionum using various evaluation endpoints, such as growth zone, chlorophyll fluorescence, and photosynthetic activity. Chlorophyll fluorescence and photosynthetic activity decreased with the increasing concentrations of Cu +2 or Ni +2 contaminated soils. Algal growth zone was analyzed visually and showed similar results to those of chlorophyll fluorescence. The direct ethanol extraction method and indirect culture medium extraction method were similarly effective; however, the former was easier to perform, while the latter might facilitate the analysis of additional endpoints in future studies. Overall, the results suggested that the paper-disc method was not only a user-friendly assay for screening soil toxicity, but also effective due to its association with indirect soil quality indicators. [ABSTRACT FROM AUTHOR]

Even though gamma radiation application, also at the minimum dosage required for disinfection, causes depolymerization and degradation of the paper substrate, recently published papers seemed, instead, to suggest that γ-rays application could be envisaged in some conditions for Cultural Heritage original documents and books. In some of the published papers, the possible application of γ-rays was evaluated mainly by using mechanical tests that scarcely reflect the chemical modifications induced in the cellulosic support. In the present article the effect of low dosage γ-irradiation on cellulosic substrates was studied and monitored applying different techniques: colorimetry, spectroscopic measurements, carbonyl content and average viscometric degree of polymerization. Two different papers were investigated, a non-sized, non-filled cotton paper, and a commercial permanent paper. To simulate a real deteriorated document, which could need γ-rays irradiation, some samples were submitted to a hydrolysis treatment. We developed a treatment based on the exposition of paper to hydrochloric acid vapors, avoiding any contact of the samples with water. This method induces a degradation similar to that observed on original documents. The samples were then irradiated with 3 kGy γ-rays at a 5258 Gy/h rate. The aforementioned analyses were performed on the samples just irradiated and after artificial ageing. All tests showed negative effects of gamma irradiation on paper. Non-irradiated paper preserves better its appearance and chemical properties both in the short term and after ageing, while the irradiated samples show appreciable color change and higher oxidation extent. Since the Istituto centrale restauro e conservazione patrimonio archivistico e librario is responsible for the choice of all restoration treatments that could be applied on library and archival materials under the protection of the Italian State ( http://www.icpal.beniculturali.it/allegati/DM-7-10-2008-Istituto.pdf ), it has been evaluated that the modifications induced by γ-rays irradiation are not acceptable as safe conservation treatment ( http://www.icpal.beniculturali.it/allegati/Nota_uso_raggi_gamma.pdf ). [ABSTRACT FROM AUTHOR]

[Display omitted] • Facile, Flexible, and Fast sensing of spike protein with SERS paper sensor. • Low-cost / Ecofriendly green assisted production of spherical silver nanoparticles. • Paper sensor detectability is 2.4 pg/ul of spike protein of SARS-CoV-2 virus. • Spike protein sensing in saliva is achieved with SERS paper sensor. • Lab on paper ensures environment sustainability by its safe disposal. Rapid investigation on the detection of spike protein with paper sensor is projected with Surface Enhanced Raman Spectroscopy (SERS). SERS sensor with lab on paper is preceded with facile, cost-effective strategy. Silver nanoparticles with average size of 20–30 nm were produced by green chemistry approaches, followed by loading the nanoparticles on hydrophobic paper surfaces. The very low %RSD (∼1.5) with mapping scan ensembles high reproducibility. Spike protein detection analysis derived the prominent finger print regions of amide bands as well abundant amnio acids (Phenylalanine-1003 cm−1, Tryptophan- 680 cm−1, Tyrosine-1473 cm−1) respectively. The detectability of sensor is gauged to be 2.4 pg / µL. Real time analysis on human saliva spiked with spike protein exhibited diagnosis within 2 min. Developed paper sensor provide us the scope of SERS technique to bring state of art in early detection of covid infections and safe disposal after its use. [ABSTRACT FROM AUTHOR]

The surface of paper was treated to control wettability using argon-carbon plasma generated by a direct current-pulsed (frequency: 60 kHz) sputtering device with parallel-arrangement magnets. After plasma treatment, the C–C bond percentage in the C 1s region was inversely proportional to the C–OH bond percentage, while the ratio of C=O and O–C=O bonds only changed slightly. The change ratios for the increase in C–C and the decrease in the C–OH bonds were approximately the same, and the change ratio increased from approximately 5%–11% with an increase in the plasma current. The reduction ratio of the contact angle decreased from 0.945 to 0.182 (°/s) with increasing plasma current. These results indicate that the water resistance of the paper surface was enhanced after the simple plasma treatment, and wettability could be easily controlled by changing the substitution ratio between C–OH and C–C elements, achieved by altering the plasma current. • Papers were plasma-treated using DC-pulsed sputtering with parallel-aligned magnets. • C–C and C–OH bond percentages were inversely proportional after plasma treatment. • Substitution ratio between C–OH and C–C was changed by varying the plasma current. • Contact angle reduction ratio on paper decreased with increase in plasma current. [ABSTRACT FROM AUTHOR]