Water Alcohol Research Articles

Compact Micro-Coriolis Mass-Flow Meter with Optical Readout.

This paper presents the first nickel-plated micro-Coriolis mass-flow sensor with integrated optical readout. The sensor consists of a freely suspended tube made of electroplated nickel with a total length of 60 mm, an inner diameter of 580 µm, and a wall thickness of approximately 8 µm. The U-shaped tube is actuated by Lorentz forces. An optical readout consisting of two LEDs and two phototransistors is used to detect the tube motion. Mass-flow measurements were performed at room temperature with water and isopropyl alcohol for flows up to 200 g/h and 100 g/h, respectively. The measured resonance frequencies were 1.67 kHz and 738 Hz for water and 1.70 kHz and 752 Hz for isopropyl alcohol for the twist and swing modes, respectively. The measured phase shift between the two readout signals shows a linear response to mass flow with very similar sensitivities for water and isopropyl alcohol of 0.41mdegg/h and 0.43 mdegg/h, respectively.

Organocatalytic Chemoselective C4‐Benzylation of 5‐Aminopyrazoles

AbstractThe first chemoselective C4‐benzylation of 5‐aminopyrazoles, utilizing a 3 mol% squaric acid catalyst, is disclosed. In this process, ortho‐quinone methides are efficiently generated from 2‐hydroxybenzyl alcohols in water under mild conditions. This method successfully delivers a wide range of C4‐benzylated 5‐aminopyrazoles, achieving moderate to excellent yields while demonstrating high chemoselectivity, which is further confirmed by mechanistic studies. Notably, the protocol uses water as an eco‐friendly solvent, requires a low organocatalyst loading, and eliminates the need for column chromatography.

Liquid–Liquid Equilibrium for Ternary Systems of Water, Methacrylic Acid, and Alkyl Alcohols: Thermodynamic Analysis and Solvent Comparison

Liquid–Liquid Equilibrium for Ternary Systems of Water, Methacrylic Acid, and Alkyl Alcohols: Thermodynamic Analysis and Solvent Comparison

Ultra-low temperature direct reconstruction of biomass fermentation of ethanol to higher alcohols in water over thermostable hcp-Ni

Near-ambient temperature direct reconstruction of biomass fermentation of ethanol to higher alcohols in water over thermostable hcp-Ni.

Understanding the active role of water in laboratory chamber studies of reactions of the OH radical with alcohols of atmospheric relevance.

In this work, we studied the reactions of three cyclic aliphatic alcohols with OH at room temperature, atmospheric pressure and different humidities in a Teflon reaction chamber. It was determined that the lower the solubility of the alcohol in water, the larger the effect of the humidity on the acceleration of the reaction. This experimental evidence allows suggesting that the acceleration is due to the reaction of the co-adsorbed reactants at the air-water interface of a thin water film deposited on the Teflon walls of the reaction chamber, instead of between co-reactants dissolved in the water film or due to gas phase catalysis as previously suggested. Therefore, formation of thin water films on different surfaces could have some implications on the tropospheric chemistry of these alcohols in the tropical regions of the planet with high humidity.

Water enhanced photo-oxidation of alcohols on colloidal quantum dots

CdS QDs were used as photocatalysts for the oxidation of benzyl alcohol in water. The combined experimental and theoretical calculation results reveal a unique phenomenon in which water acts as an “accelerator” for the oxidation reaction.

КОЭФФИЦИЕНТЫ ДИФФУЗИИ И АКТИВНОСТЬ КОМПОНЕНТОВ ВОДНОСПИРТОВЫХ СМЕСЕЙ В ПОЛИУРЕТАНОВЫХ ПЛЕНКАХ НА ОСНОВЕ АМИНОЭФИРОВ БОРНОЙ И ОРТОФОСФОРНОЙ КИСЛОТ

The work carried out studies to determine the diffusion coefficients and activities of water, isopropyl and ethyl alcohols in polymer polyurethane films based on amino esters of boric and orthophosphoric acids at temperatures of 22, 40 and 60 °C. To determine the diffusion coefficients, we used data on the dynamics of sorption of low molecular weight components in the polymers under study, presented in our previous study. To describe the process of swelling of a polymer film, the Fick differential equation was used; the process was represented as unsteady diffusion in a flat plate. The initial condition was the absence of a component in the polymer at the initial moment of time; the solution to the differential equation was the non-stationary field of concentrations of the component in the film. The experimental dependences of changes in the volume-mass concentration of components in the polymer were described using the Heaviside switching function; due to the presence of a maximum in the swelling curve, it is associated with a restructuring of the polymer structure that occurs due to possible relaxation processes. By minimizing the discrepancies between the calculated and experimental values of the concentration versus time dependence, the diffusion coefficients of pure components in AEPA and AEBA films were determined. Based on data on the diffusion of components through polymer films, the separation characteristics of polymers were assessed for their use as a selective layer of pervaporation membranes. Based on swelling data over long periods of time for water-alcohol mixtures of various compositions, the parameters of the Flory-Huggins model were determined for calculating the activities of components in the polymer. It was shown that among the solvents under study, water has the highest diffusion coefficient, and isopropyl alcohol has the lowest, regardless of the type of film (AEPA/AEBA). For all films, there is a tendency for the diffusion coefficient to increase with increasing temperature, regardless of the solvent.

НАБУХАНИЕ ПОЛИУРЕТАНОВЫХ ПЛЕНОК НА ОСНОВЕ АМИНОЭФИРОВ БОРНОЙ И ОРТОФОСФОРНОЙ КИСЛОТ В ВОДНЫХ РАСТВОРАХ СПИРТОВ

In this work we have carried out studies to determine the sorption capacity (swelling) of polymer polyurethane films based on amino esters of boric and orthophosphoric acids in pure components (water, isopropyl and ethyl alcohols) and water-alcohol mixtures (isopropanol-water, ethanol-water) at temperatures of 22, 40 and 60 °С. On the basis of the data on the sorption capacity of components through polymer films a preliminary assessment of the prospects of using the investigated polymers as a selective layer of pervaporation membranes is made. The changes in the volume-mass concentration of low-molecular-weight components in polymer films depending on the solvent concentration in the initial mixture and the temperature of the process have been determined experimentally. The obtained data are necessary for creating a mathematical model of the pervaporation separation process. The paper describes the developed methodology for the fabrication of polymer films based on amino esters of orthophosphoric and boronic acids. Hyperbranched polyols with high solubility and low characteristic viscosities were used as crosslinking agents in the synthesis of the studied polymers Experimental studies for water-alcohol mixtures were carried out in a wide range of alcohol concentrations (0-99 wt.%). The swelling dynamics of polymer films in water-alcohol mixtures and individual components were measured. For all films, a tendency of decreasing volume-mass concentration with increasing process temperature in isopropyl alcohol and water can be seen, but in ethyl alcohol the volume-mass concentration increases with exceeding the process temperature.

An RF Ring Resonator across Fluidic Media for Dielectric Sensing and Air-bubble Detection

Design, fabrication, and characterizations of an RF ring resonator used as a dielectric sensor, air-bubble detector and droplet sizer inside fluidic media are presented. The resonator with a split in its design has been analyzed and optimized using numerical methods and design guidelines are established to select the most sensitive resonance mode. A tube with an inner diameter of 800 µm placed over the 350 µm split is used to bring liquids and test samples. Different types of liquids (Isopropyl alcohol and de-ionized water) are easily distinguished by frequency shifts in the resonance peak. For instance, a 5 MHz frequency shift between air and water is observed. Furthermore, uniform oil droplets (0.6mm and 2.8mm long) were passed through the tube and measured to demonstrate the transient response of the sensor in detecting droplet sizes.

The study of perspective medicinal plants using the example of Helianthus tuberosus L.

This paper presents the results of microscopic analysis of a perspective medicinal plant Helianthus tuberosus used for the treatment of diabetes mellitus. The study was conducted to identify specific morphological and structural characteristics of this plant, which may have a positive impact on the efficacy and safety of its use for medical purposes. Different types of plant material were used in the research: fresh plants, dried plant material and preserved plant material. For preservation of the latter, a special mixture consisting of ethyl alcohol, glycerol and distilled water in equal volumes was used. Anatomical study of the structure and structure of plants was carried out using several methods: to study the structure of the epidermis, surface samples were prepared, which allowed us to get a detailed idea of the cellular composition and location of the epidermis on the surface of leaves, stems and roots of plants; for a deeper study of the internal structure of plants, transverse sections were made, which were further investigated. The results of the study suggest the high potential of this plant as a basis for the development of safe and effective phytopreparations.

Distance-based detection of paracetamol in microfluidic paper-based analytical devices for forensic application.

Whisky adulteration is a prevalent practice driven by the high cost of these beverages. Counterfeiters commonly dilute whisky with less expensive alcoholic beverages, water, food additives, drugs or pharmaceuticals. Paracetamol (PAR), an analgesic drug that mitigates hangovers and headaches, is commonly used to adulterate whisky. Currently, the primary method for quantifying PAR levels is high-performance liquid chromatography, but this technique is both time consuming and usually generates more residues. In this context, the utilization of miniaturized and portable analytical devices becomes imperative for conducting point-of-care/need analyses. These devices offer several advantages, including portability, user-friendliness, low cost, and minimal material wastage. This study proposes the selective distance-based PAR quantification on whisky samples using a paper-based microfluidic analytical device (μPAD). Colorimetric detection on paper-based platforms offers great benefits such as affordability, portability, and the ability to detect PAR without complicated instrumentation. The optimal detection conditions were achieved by introducing 5 μL of a mixture containing 7.5 mmol L-1 of Fe(III) and K3[Fe(CN)6] into the detection zone, along with 12 μL of whisky samples into the sample zone. The method exhibited linear behavior within the concentration range from 15 to 120 mg L-1, with a determination coefficient of 0.998. PAR was quantified in adulterated samples. The results obtained with the paper-based devices were compared with a referenced method, and no significant differences were observed at a confidence level of 95%. The μPAD allowed to determine ca. 1 drop of pharmaceutical medicine PAR of 200 mg mL-1 in 1 L of solution, demonstrating excellent sensitivity. This method offers cost-effective and rapid analysis, reducing the consumption of samples, reagents, and wastes. Consequently, it could be considered a viable and portable alternative for analyzing beverages at criminal scenes, customs, and police operations, thereby enhancing the field of forensics.

Solvation dynamics on the diffusion timescale elucidated using energy-represented dynamics theory.

Photoexcitation of a solute alters the solute-solvent interaction, resulting in the nonequilibrium relaxation of the solvation structure, often called a dynamic Stokes shift or solvation dynamics. Thanks to the local nature of the solute-solvent interaction, the characteristics of the local solvent environment dissolving the solute can be captured by the observation of this process. Recently, we derived the energy-represented Smoluchowski-Vlasov (ERSV) equation, a diffusion equation for molecular liquids, which can be used to analyze the solvation dynamics on the diffusion timescale. This equation expresses the time development for the solvent distribution on the solute-solvent pair interaction energy (energy coordinate). Since the energy coordinate can effectively treat the solvent flexibility in addition to the position and orientation, the ERSV equation can be utilized in various solvent systems. Here, we apply the ERSV equation to the solvation dynamics of 6-propionyl-2-dimethylamino naphthalene (Prodan) in water and different alcohol solvents (methanol, ethanol, and 1-propanol) for clarifying the differences of the relaxation processes among these solvents. Prodan is a solvent-sensitive fluorescent probe and is thus widely utilized for investigating heterogeneous environments. On the long timescale, the ERSV equation satisfactorily reproduces the relaxation time correlation functions obtained from the molecular dynamics (MD) simulations for these solvents. We reveal that the relaxation time coefficient on the diffusion timescale linearly correlates with the inverse of the translational diffusion coefficients for the alcohol solvents because of the Prodan-solvent energy distributions among the alcohols. In the case of water, the time coefficient deviates from the linear relationship for the alcohols due to the difference in the extent of importance of the collective motion between the water and alcohol solvents.

Pengaruh waktu induksi dan ZPT terhadap pertumbuhan kalus kotiledon kacang panjang (Vigna unguiculata subsp. sesquipedalis)

Yard-Long bean plants are an agricultural commodity that has great potential to be developed because they are easy to cultivate, their market share is also quite high but there are still problems in meeting the need for sufficient seeds and they are still susceptible to pests and disease. Therefore, efforts need to be made to increase production and induce variations. One method that can be used is tissue culture for the induction of somaclonal variations and/or the formation of transgenic plants. This study aims to determine the effect of variations in callus initiation time and the effect of Plant Growth Regulators (PGR) administration on the growth of long bean cotyledon explant callus. Seed sterilization was carried out using detergent, 10% sodium hypochlorite, 70% alcohol and sterile distilled water. The results of the research showed that variations in callus initiation time on MS media with the addition of 2,4-D PGR and the use of several variations of PGR in subcultures were able to initiate callus and influence callus size, callus color, and the percentage of browning of Yard-long bean cotyledon explants. Callus initiation time of 4 weeks with a combination of 2 ppm BAP concentration with 0.1 ppm IAA produced the largest callus size and brownish white callus color. The addition of PGR during subculture had a smaller browning percentage than the treatment without PGR.

Quality Parameters of Polyherbal Formulation of Three Different Marketed Brands of Vilwadi Gutika: A Comparative Evaluation Study

Background: Ayurveda is a highly beneficial medical system due to its natural components that effectively eliminate disease causes, restore balance, and prevent further recurrence. Polyherbal formulations are highly popular due to their wide therapeutic range, making them safe at high doses and producing minimal negative effects when taken improperly. The goal of this study was to standardize the efficacy and quality of commercial herbal tablet formulations. Methods: Three marketed samples of vilwadi Gutika ware used for the study. After authentication of the samples, the phytochemical stander like determination of pH, ash value, acid insoluble ash, water soluble ash, water soluble extractive, alcohol and soluble extractive were determined. In vitro anti-microbial activity was determined using Agar well diffusion method and the anti – inflammatory activity of Vilwadi tablet of different ayurvedic agency was assessed by in- vitro HRBC (Human Red Blood Cells) membrane stabilization method. Results: The physicochemical properties of polyherbal pills met Pharmacopeial criteria, including pH, ash value, hardness, and friability. Sample 1 was the most acceptable, with a noticeable hardness (0.93) for rapid disintegration. The sample 3 (Vilwadi gutika – Arya Vaidya Pharmacy, Coimbatore) exhibited the highest antimicrobial activity against E. coli, Staphylococcus sp, and Candida sp, while sample 1 showed the highest activity against E. coli and Staphylococcus sp, and less activity against Candida sp. The in vitro anti-inflammatory activity shown that at concentration of 100µg / ml, the test compound inhibited 66.6 % of RBC haemolysis as compared with 54.16 % produced by Indomethacin (positive control) at 100µg / ml. Conclusion: The investigation reveals that the Viladi gutika herbal formulation can be standardized using a scientific quality control technique, meeting Indian pharmacopoeia requirements for tablet dosage form, with further research needed to analyze other characteristics. Keywords: Viladi gutika, anti-microbial activity, anti-inflammatory activity.

Synthesis of Poly[N‐(2‐((3‐Morpholino‐3‐Oxopropyl)Thio)Ethyl)Methacrylamide]: A New Thermoresponsive Polymer with Tunable LCST‐ and UCST‐Type Phase Transition in Aqueous and Alcoholic Solutions

AbstractA novel monomer, N‐(2‐((3‐morpholine‐3‐isopropyl)thio)ethyl)methacrylamide (MTMA), is synthesized and polymerized by reversible addition‐fragmentation chain transfer (RAFT) polymerization to give a thermoresponsive polymer poly[N‐(2‐((3‐morpholino‐3‐oxopropyl)thio)ethyl)methacrylamide] (PMTMA). PMTMA exhibits reversible thermoresponsive phase transitions of the lower critical solution temperature (LCST) type in water and the upper critical solution temperature (UCST) type in ethanol and methanol. The degree of polymerization and concentration of PMTMA, and solvent type have a significant influence on the transition temperature. PMTMA shows complicated thermoresponse in water–alcohol mixtures. In water–ethanol mixtures, the phase diagram of PMTMA can be divided into three regions according to ethanol volume percentages, φ: 0 ≤ φ < 15% for an LCST region; 15% ≤ φ < 91.5% for a complete dissolution region; 91.5% ≤ φ ≤ 100% for a UCST region. At high water content, the LCST increases with increasing ethanol content; and at high ethanol content, the UCST decreases with increasing water content. In water–methanol mixtures, PMTMA shows more complex thermoresponse. In the range of 0–50 °C, the phase diagram can be divided into five regions, depending on the methanol volume percentages φ: 0 ≤ φ < 15% for LCST region; 15% ≤ φ < 25% for immiscible region; 25% ≤ φ < 85% for UCST region; 85% ≤ φ < 95% for fully dissolved region; 95% ≤ φ ≤ 100% for another UCST region.

Conformational states of NADH in water–alcohol solutions studied by molecular dynamics simulations

Redox reactions in living cells involving a coenzyme nicotinamide-adenine-dinucleotide (NAD) are stereospecific and depend on NAD conformation states and on the structure of enzyme binding sites. Therefore, information on NAD conformation states in various environments is important for understanding of the mechanisms of redox reactions. In this paper the structural dynamics of reduced nicotinamide-adenine-dinucleotide (NADH) in water–methanol and water–ethanol solutions was investigated by means of molecular dynamics simulations. The trajectory analysis revealed three stable conformation groups characterized by the distance RNA−AD between adenine and nicotinamide centers of mass: folded (RNA−AD< 5.5 Å), intermediate (5.5 Å <RNA−AD< 12 Å) and unfolded (RNA−AD> 12 Å). It was shown that conformation equilibrium shifted from the folded conformation group at low alcohol concentrations towards the intermediate conformation group at high alcohol concentrations, while the fractional concentration of unfolded conformation group remained almost constant. The nicotinamide and adenine rings were found to be almost parallel in folded conformations and perpendicular in intermediate conformations, while no preferable positions of the rings were found in unfolded conformations. The results obtained were used for the analysis of experimentally determined rotational diffusion times τrexp in NADH in water–methanol and water–ethanol mixtures. Comparison between the calculated and experimental τr values using the generalized Stokes–Einstein–Debye equation allowed for determination of the wettability coefficient C and effective molecular volume Vm as a function of alcohol concentration. The coefficient C was found to be always less than unity and have a minimum at 40% of alcohol which was more pronounced for ethanol than for methanol mixtures. This dependence was attributed to the influence of solution viscosity that has a maximum at 40% of alcohol. The effective molecular volume Vm was found to be practically constant at alcohol concentrations below 60% and rise dramatically at higher alcohol concentrations. This dependence was attributed to the solvation of NADH at high alcohol concentrations.

Enhancing Photoredox Catalysis in Aqueous Environments: Ruthenium Aqua Complex Derivatization of Graphene Oxide and Graphite Rods for Efficient Visible-Light-Driven Hybrid Catalysts.

A ruthenium aqua photoredox catalyst has been successfully heterogeneneized on graphene oxide (GO@trans-fac-3) and graphite rods (GR@trans-fac-3) for the first time and have proven to be sustainable and easily reusable systems for the photooxidation of alcohols in water, in mild and green conditions. We report here the synthesis and total characterization of two Ru(II)-polypyridyl complexes, the chlorido trans-fac-[RuCl(bpea-pyrene)(bpy)](PF6) (trans-fac-2) and the aqua trans-fac-[Ru(bpea-pyrene)(bpy)OH2](PF6)2 (trans-fac-3), both containing the N-tridentate, 1-[bis(pyridine-2-ylmethyl)amino]methylpyrene (bpea-pyrene), and 2,2'-bipyridine (bpy) ligands. In both complexes, only a single isomer, the trans-fac, has been detected in solution and in the solid state. The aqua complex trans-fac-3 displays bielectronic redox processes in water, assigned to the Ru(IV/II) couple. The trans-fac-3 complex has been heterogenized on different types of supports, (i) on graphene oxide (GO) through π-stacking interactions between the pyrene group of the bpea-pyrene ligand and the GO and (ii) both on glassy carbon electrodes (GC) and on graphite rods (GR) through oxidative electropolymerization of the pyrene group, which yield stable heterogeneous photoredox catalysts. GO@trans-fac-3- and GR/poly trans-fac-3-modified electrodes were fully characterized by spectroscopic and electrochemical methods. Trans-fac-3 and GO@trans-fac-3 photocatalysts (without a photosensitizer) showed good catalytic efficiency in the photooxidation of alcohols in water under mild conditions and using visible light. Both photocatalysts display high selectivity values (>99%) even for primary alcohols in accordance with the presence of two-electron transfer processes (2e-/2H+). GO@trans-fac-3 keeps intact its homogeneous catalytic properties but shows an enhancement in yields. GO@trans-fac-3 can be easily recycled by filtration and reused for up to five runs without any significant loss of catalytic activity. Graphite rods (GR@trans-fac-3) were also evaluated as heterogeneous photoredox catalysts showing high turnover numbers (TON) and selectivity values.

Zwitterionic Aqua Palladacycles with Noncovalent Interactions for meta-Selective Suzuki Coupling of 3,4-Dichlorophenol and 3,4-Dichlorobenzyl Alcohol in Water.

The site-selective reaction of substrates with multiple reactive sites has been a focus of the current synthetic chemistry. The use of attractive noncovalent interactions between the catalyst and substrate is emerging as a versatile approach to address site-selectivity challenges. Herein, we designed and synthesized a series of palladacycles, to control meta-selective Suzuki coupling of 3,4-dichlorophenol and 3,4-dichlorobenzyl alcohol. Noncovalent interactions directed zwitterionic aqua palladacycles catalyzed meta-selective Suzuki couplings of 3,4-dichloroarenes bearing hydroxyl in water have been developed. Experiments and density functional theory (DFT) calculations demonstrated that the electrostatic interactions play a critical role in meta-selective coupling of 3,4-dichlorophenol, while meta-selective coupling of 3,4-dichlorobenzyl alcohol arises due to the hydrogen-bonding interactions.

CONSERVATION PROCESSES OF A WOODEN COFFIN COVERED WITH A BLACK RESIN LAYER AND COLORED MATERIALS IN DAHSHUR ARCHAEOLOGICAL AREA

This paper describes the results of a multi-technological analytical protocol performed on the painted surface of an Egyptian wooden coffin and documents the conservation processes of a wooden coffin covered with a black resin layer and coloured materials in Dahshur Archaeological Area dating back to the late period. It uses visual observation, optical microscopy (OM), technical imaging, 2D and 3D programmes, and a scan made using an electron microscope coupled with an Energy Dispersive X-ray (SEM-EDX), X-ray diffraction (XRD). Wood identification was also carried out. The results showed the use of yellow ochre for the yellow painted layer; the ground layer was calcium carbonate with gypsum, and the fabric layer was linen. The conservation processes of the wooden coffin included mechanical and chemical cleaning; reassembling the separated wooden parts, ground layer, and black resin layers; filling the edge of the ground layer; and consolidating the wood, black resin, and painted layer. The conservation processes included mechanical cleaning using soft brushes, chemical cleaning using xylene and distilled water for the black resin layer and ethyl alcohol and distilled water for the painted layer, stabilisation of the separated ground layer using Paraloid B72, filling the cracks of the ground layers using glass microballoons with Paraloid B72, and consolidating the painted layer with nano-silica with Klucel G (hydroxypropyl cellulose) (0.5% concentration).

ANALYSIS AND RESTORATION OF GRECO-ROMAN POTTERY IN EGYPT

The research aims to identify features of the industry and assess the pottery damage through various examinations and analyses, such as examination by polarised microscope (PLM), examination by Scanning Electron Microscope with Energy Dispersive X-ray unit "SEM-EDX", analysis by X-ray diffraction powder XRD, and thermal analysis TGA. Archaeometric features of archaeological pottery were identified. The used clay is Nile Clay; the additives are sand, limestone powder, pottery powder (grog), and straw. The moulding technique is the hand and potter wheel technique. The surface treatment is a red wash and slip layer. The burning atmosphere is oxidising for the first and second pottery pieces and reducing for the third and fourth pottery pieces. The burning temperature is about 816°C for the first sample, 887°C for the second sample, 706°C for the third sample, and 651°C for the fourth sample. The texture is medium to coarse fabric for the first sample; the second sample fabric is fine; and the third and fourth samples have a coarse texture. The research proved that the pottery objects suffer from some different damage aspects such as fracture, loss of some parts, lack of strength, weakness, cracking, soil sediments, soot spots and black core, and salt crystallisation (chloride, sulphate, carbonate, and phosphate salts). The research proved the use of a mixture of distilled water, acetone, and ethyl alcohol at a ratio of 1:1:1, respectively, for removing clay soil deposits. EDTA is used to remove lime deposits. Nano-silica at a concentration of 0.5% is used to strengthen archaeological pottery by spraying. Paralloid B 82 dissolved in trichloroethylene at a concentration of 50% in assembling the pottery sherds; it is preferable to display it in the museum at a temperature of 20°C and a relative humidity of 55:60%.