Thermophysical Parameters of a Semi-Finished Watermelon Product as an Object of Dehumidification

Introduction. Pectin-based protective coatings can produce a perfect biodegradable edible film. Secondary watermelon raw materials are a promising resource for this type of food coating as it contains 13.4% of pectin components, of which 8.1% is protopectin. The present research objective was to find the density and thermophysical characteristics of the pectin extract in order to optimize the drying process. Study objects and methods. The research featured a pectin extract from watermelon rind. Its thermophysical properties were defined according to the thermocouple inertia method. The calorimetric method was used to change the aggregation state, while the pycnometric method was applied to calculate the density. The method of criterion equations helped to define the heat transfer coefficient. Results and discussion. The average density of the final film material was 652 kg/m3 and that of the liquid semi-finished product was 1,028 kg/m3. The research also revealed the dependence of physical density and humidity W, heat capacity, thermal diffusivity, and thermal conductivity. For different W, averaged were 3393, 3225, 3137, and 3113, respectively. The study also provided the criterion dependence for determining the heat transfer coefficient and modified α on the speed of the air coolant for artificial convection at conventional coolant temperature (≈ 100°C) in contact with the food product surface (≈ 80°C). Conclusion. The article introduces the thermophysical characteristics and physical density of watermelon gel for various humidity and thermal agent parameters, as well as a modified criterion dependence for determining the heat transfer coefficient. The research results can be used to design dehydration operations, other thermophysical processes, and their equipment.

Thermal dependencies of fruit puree density

Density is among the key properties of liquid food media, affecting homogenisation and dispersion. The work aimed to study the temperature effect on fruit puree density, determine temperature constants and grade purees by density. The study included apple, pear and cherry plum purees. Pycnometric densities were measured at 20, 30, 40 and 50ºC temperatures. Different media were shown to vary in the density reduction rate at increasing measurement temperatures. The correlation coefficient was strongly dependent on the reference (baseline) density and extremely — on temperature coefficient. Correlation dynamics modelling of elevating temperature revealed the slope vs. temperature coefficient pairwise correlation to monotonously increase starting from very high baseline values of >0.999. The relative slope vs. baseline density pairwise correlation coefficient decreased monotonously from 0.9032. It was additionally found that the media density grading is temperature-dependent. Thus, the descending series was pear–apple–cherry plum at 0–+24.68ºC, pear–cherry plum–apple at +24.68–+84.34ºC, cherry plum–pear–apple at +84.34–+174.31ºC and cherry plum–apple–pear at ≥+174.31ºC. For three study media, the number of temperature ranges inducing puree density gradients was 4. This approach to study thermal impact on the density of food fluids is generally acknowledged and can be successfully applied in the areas, where physical density and its comparative assessment are substantive.

A sustainability assessment framework for population density in central Indian cities

PurposeThe urban population in Indian cities is increasing at an alarming speed. Accommodating such a huge population while sustaining the environment is a challenge in urban areas. Compact urban forms with high-density planning is claimed to be a sustainable solution in such situations. Thus, this approach needs to be tested for Indian urban areas.Design/methodology/approachThis paper formulates a neighbourhood sustainability assessment (NSA) framework for monitoring, assessing and managing the population density of urban neighbourhoods. The paper identifies context-specific built density indicators at the neighbourhood scale. It assesses the indicators in neighbourhoods with varying population density by physical and perceived measures. This helps in verifying the feasibility of density by physical density assessment and verifies the acceptability of density by perceived density assessment.FindingsWhen tested in the Indian context, the framework shows that although high-density neighbourhoods are sustainable, certain indicators may endorse differing densities. The result displays that high-density planning is sustainable compared to low- and medium-density neighbourhoods in the selected cities.Practical implicationsThe study demonstrates the application of formulated assessment system in three central Indian cities with useful results. Similar studies can be conducted to identify the gaps for improving sustainability and achieve a livable density pattern.Originality/valueAlthough sustainable development goals are part of new planning policies, there exist very few assessment systems to determine the sustainability of neighbourhoods, especially for density. The methodology will assist in developing sustainability assessment frameworks and encourage the practice of sustainability assessment in developing countries like India.

Energy intensity of hydrocarbons in liquid and solid states

Objectives. The increased use of unmanned aerial vehicles necessitates the search for jet fuels based on hydrocarbon materials with high energy intensity and physical density. The purpose of the work was to analyze the influence of various factors on the mass energy intensity of hydrocarbons. This analysis is required to substantiate the algorithm for locating energy-intensive CnHm structures.Methods. Combustion energy was calculated using additive procedures. The calculations were performed using Microsoft Excel.Results. During the analysis of the mass energy intensity of CnHm hydrocarbons, the m/n ratio was discovered to be the decisive factor for achieving high values of the mass energy intensity of hydrocarbons. The energy intensity decreases when moving from alicyclic to cyclic hydrocarbons, and this decrease is not compensated by the production of strain energy. An additive scheme that allows the molar volume of hydrocarbons to be predicted with sufficient accuracy is proposed for calculating the volumetric enthalpies of combustion.Conclusions. According to the thermodynamic analysis, n-alkanes have the highest mass energy intensities. The technology for extracting n-alkanes from oil fractions is well developed, and a decrease in the hydrogen content in the fuel results in a decrease in the mass energy intensity. It appears improbable that the mass and volumetric energy intensities of hydrocarbons seem will reach their maximum values simultaneously. Hydrocarbons that have a high m/n value, 2, 3, 4, 5, 6-membered rings, and phenyl fragments may have relatively high mass and volumetric energy intensities at the same time.

Physical density estimations of single- and dual-energy CT using material-based forward projection algorithm: a simulation study

Objectives: This study aims to evaluate the accuracy of physical density prediction in single-energy CT (SECT) and dual-energy CT (DECT) by adapting a fully simulation-based method using a material-based forward projection algorithm (MBFPA). Methods: We used biological tissues referenced in ICRU Report 44 and tissue substitutes to prepare three different types of phantoms for calibrating the Hounsfield unit (HU)-to-density curves. Sinograms were first virtually generated by the MBFPA with four representative energy spectra (i.e. 80 kVp, 100 kVp, 120 kVp, and 6 MVp) and then reconstructed to form realistic CT images by adding statistical noise. The HU-to-density curves in each spectrum and their pairwise combinations were derived from the CT images. The accuracy of these curves was validated using the ICRP110 human phantoms. Results: The relative mean square errors (RMSEs) of the physical density by the HU-to-density curves calibrated with kV SECT nearly presented no phantom size dependence. The kV–kV DECT calibrated curves were also comparable with those from the kV SECT. The phantom size effect became notable when the MV X-ray beams were employed for both SECT and DECT due to beam-hardening effects. The RMSEs were decreased using the biological tissue phantom. Conclusion: Simulation-based density prediction can be useful in the theoretical analysis of SECT and DECT calibrations. The results of this study indicated that the accuracy of SECT calibration is comparable with that of DECT using biological tissues. The size and shape of the calibration phantom could affect the accuracy, especially for MV CT calibrations. Advances in knowledge: The present study is based on a full simulation environment, which accommodates various situations such as SECT, kV–kV DECT, and even kV–MV DECT. In this paper, we presented the advances pertaining to the accuracy of the physical density prediction when applied to SECT and DECT in the MV X-ray energy range. To the best of our knowledge, this study is the first to validate the physical density estimation both in SECT and DECT using human-type phantoms.

From acoustic to elastic inverse extended Born modeling: a first insight in the marine environment

Elastic least-squares reverse time migration is the state-of-the-art linear imaging technique to retrieve high-resolution quantitative subsurface images. A successful application requires many migration/modeling cycles. To accelerate the convergence rate, various pseudoinverse Born operators have been proposed, providing quantitative results within a single iteration, while having roughly the same computational cost as reverse time migration. However, these are based on the acoustic approximation, leading to possible inaccurate amplitude predictions as well as the ignorance of S-wave effects. To solve this problem, we extend the pseudoinverse Born operator from acoustic to elastic media to account for the elastic amplitudes of PP reflections and provide an estimate of physical density, P- and S-wave impedance models. We restrict the extension to marine environment, with the recording of pressure waves at the receiver positions. Firstly, we replace the acoustic Green's functions by their elastic version, without modifying the structure of the original pseudoinverse Born operator. We then apply a Radon transform to the results of the first step to calculate the angle-dependent response. Finally, we simultaneously invert for the physical parameters using a weighted least-squares method. Through numerical experiments, we first illustrate the consequences of acoustic approximation on elastic data, leading to inaccurate parameter inversion as well as to artificial reflector inclusion. Then we demonstrate that our method can simultaneously invert for elastic parameters in the presence of complex uncorrelated structures, inaccurate background models, and Gaussian noisy data.

Preparation and Evaluation of Biodegradation Performance of Potato Starch Mixed LDPE Polymer Composites

The potential of biodegradable polymers has long been appreciated. In this work, an attempt has been made to synthesize biodegradable polymer composite from potato starch and low density polyethylene (LDPE) with different ratios of starch (0%-15% w/w) by using an extruder. The structure and morphology of film surfaces was studied using X-ray diffraction and scanning electron microscopy (SEM) respectively. The physical (density, water absorption), mechanical (tensile, flexural) and thermal (TGA and DTA) analyses of starch/LDPE bio-composites were evaluated through standard methods and instruments. Biodegradation tendency was investigated utilizing soil burial and Rockwell micro-hardness test.The results revealed that the density and water absorption of polymer blends increased with increasing the starch content in starch/LDPE composites. The tensile strength and elongation at break decreased with starch content whereas the elastic modulus, flexural strength and flexural modulus rose. The biodegradability of composites enhanced by increasing the starch content and the result was backed by weight loss during burial of the samples in soil for 90 days. Microhardness test also supported the biodegradation probability as hardness found to reduce extensively after soil burial. However, further study to decide the optimum starch loading alongwith some modifications to starch and LDPE is highly suggested to have a biodegradable LDPE polymer composite in a realistic time frame.

Ground tire rubber/polyamide 6 thermoplastic elastomers produced by dry blending and compression molding

This study investigates the addition of ground tire rubber (GTR) into virgin polyamide 6 (PA6) to produce thermoplastic elastomer (TPE) blends. In particular, a wide range of GTR concentration (0–100% wt.) was possible by using a simple dry blending technique of the materials in a powder form followed by compression molding. The molded samples were characterized in terms of morphological (scanning electron microscopy), physical (density and hardness) and mechanical (tension, flexion and impact) properties. The results showed a decrease in tensile and flexural moduli and strengths with GTR due to its elastomeric nature. However, significant increases were observed on the tensile elongation at break (up to 167%) and impact strength (up to 131%) compared to the neat PA6 matrix. Based on the results obtained, an optimum GTR content around 75% wt. was observed which represents a balance between high recycled rubber content and a sufficient amount of matrix to recover all the particles. These results represent a first step showing that a simple processing method can be used to produce low cost PA6/GTR compounds with a wide range of physical and mechanical properties.

Physico-mechanical properties of the wood of freijó, Cordia goeldiana (Boraginacea), produced in a multi-stratified agroforestry system in the southwestern Amazon

ABSTRACT Agroforestry systems (AFSs) integrate, through sustainable practices, agricultural and forest crops for the production of wood and food, providing environmental services, and conserving biodiversity. The freijó (Cordia goeldiana) has potential for cultivation in the Amazon for timber purposes, but data on the characteristics of its wood produced in AFSs are scarce. Our objective was to determine the physical-mechanical properties and suggest technological applications of freijó wood produced in a multi-stratified AFS established in the state of Rondônia, Brazil in 1996. Agricultural and forest species were established in the AFS in double rows with 5.0-m x 2.5-m spacing. Three 19-year-old freijó trees were harvested for chemical, physical (density and dimensional stability), and mechanical (compression, static bending, Janka hardness, and shear strength) characterization of the wood. The wood presented a chemical composition similar to tropical hardwoods, was moderately heavy (582.63 kg m-3), and had high dimensional stability in comparison with other consecrated woods on the market (longitudinal, radial, and tangential retraction = 0.25, 4.27, and 6.83%, respectively). The values determined for parallel (32.32 MPa) and perpendicular compression (8.02 MPa), specific strength (55.32 MPa kg-1 m-3), parallel (2373.33 N) and perpendicular Janka hardness (2326.67 N), strength to static bending (63.5 MPa), and shear (5.94 MPa) were similar to the values observed in other high-density tropical woods grown in either monoculture plantations or natural forests. The wood under study is suitable for manufacture of high-value-added products, such as fine furniture, residential floors, musical instruments and structural pieces.

RELATIONSHIP BETWEEN PHYSICAL AND CHEMICAL PROPERTIES OF ENTISOLS-FLUVENTS AND EROSION IN THE SÃO FRANCISCO RIVER

ABSTRACT The intense anthropization in the lower São Francisco River and surrounding areas can lead to environmental degradation risks and, above all, makes the area more susceptible to soil erosion. This study aimed to identify and correlate the physical and chemical properties able to enhance erosive processes and slope instability in the watercourse margins of the lower São Francisco River, in Sergipe State, Brazil. To this end, disturbed and undisturbed samples of an Entisol-Fluvent soil were collected in the region, specifically in the city of Amparo de São Francisco. Physical (density, porosity, and texture) and chemical (pH, cation exchange capacity, base saturation, micro-, and macronutrients) analyses were performed. All physical properties and organic carbon contents were higher in the surface layers (Ap and AC) compared to the others. Organic carbon, phosphorus, and micronutrients had a negative correlation with soil density, showing higher contents and lower soil densities in the Ap and AC layers. The pedological characteristics of the evaluated soil layers are unable to provide soil resistance to water erosion.