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Investigation of the adhesion performance of some fast-growing wood species based on their wettability

  • Eka Mulya Alamsyah EMAIL logo , Yoyo Suhaya , Sutrisno , Yayat Hidayat , Takashi Tanaka and Masaaki Yamada
Published/Copyright: June 11, 2021

Abstract

The objective of this study was to investigate the adhesion performance of eight fast-growing wood species, namely, Enterolobium cyclocarpum, Paraserianthes falcataria, Shorea sp., Toona sinensis, Gmelina arborea, Pinus merkusii, Acacia mangium, and Acacia hybrid obtained from the tropical region. The wettability test was conducted by contact angle measurement, while the adhesion performance was expressed by strength retention (SR) and wood failure (WF) percentages through block shear tested under the Japanese Agricultural Standard (JAS). Results showed that smaller contact angle for P. falcataria followed by E. cyclocarpum, P. merkusii, T. sinensis, and Shorea indicated that the surfaces were easier to be glued than that of G. arborea, A. mangium, and A. hybrid. It is indicated that high wettability of P. falcataria, E. cyclocarpum, P. merkusii, T. sinensis, and Shorea resulted in the better adhesive spread and more intimate contact between the wood surface and the adhesive as shown by their high SR with high WF percentages.

1 Introduction

The performance of the adhesive joint is determined by the physical and mechanical conditions of the surface of the material because the adhesive has a function to glue two surface areas. Therefore, before the wood is glued, the surface condition of the wood must meet several criteria, such as a smooth, even texture, free from dirt, free from machine marks, no raised or peeled fibers, and others. Pretreatment such as drying and evaporation given to the wood to be glued should not be excessive so that it diffuses to the surface because it will pollute and permanently close the pores of the wood cells. Chemically the surface of the wood can become inactive during the bonding process due to chemical contamination in the surrounding air, chemical components, and extractive substances that block the gluing process, oxidation, and pyrolysis due to excessive drying, the addition of preservatives to the adhesive, the addition of fire retardants to the adhesive, and the addition of other chemicals. Overall, the one that has the most negative effect is the presence of extractive substances because it can be a major contributor to the inactivation of the wood surface, which ultimately causes the ability of the wood to absorb the adhesive to be reduced. This is especially true for resin species, such as southern pine and Douglas-fir. Currently, the most common solvent used in the adhesive is water. In some of wood species that contain an extractive substance, this makes it difficult for the adhesive to wet the surface, it flows so that it is difficult to penetrate the pores. This is in line with the statement that the acidity of several hardwood species and oaks from Southeast Asia can interfere with the bonding process (Vick 1999). To determine the ability of a material in the bonding process, it is necessary to understand its density, acidity (pH), and the level of wettability of the material itself (Freeman 1959). The approach taken to determine the surface wettability of wood is to refer to the rate or how fast the liquid can wet and spread on the surface and be absorbed into the pores (Wellons 1980).

The wetting and spreading of the liquid involve the principles of surface tension and thermodynamics. Wettability is a quick method for predicting the gluability of unknown species, which can be measured by determining the contact angle between the solid–liquid interface and liquid–air surface (Bodig 1962). The contact angle is defined as the angle formed between the wood surface that is free of the liquid and the curved line of the liquid. When the absorption energy on the wood surface is high, the contact angle will be close to zero, and at the same time, the affinity value and the adhesive surface tension are low. If we drop a certain amount of adhesive and spread it to form a thin film layer so that the contact angle is close to zero degrees, the adhesive will spread well and form a strong contact with the surface area it is attached to (Vick 1999).

Wood is one of the main commodities in Indonesia, which is needed as a raw material for various needs that continue to increase. However, now wood production from natural forests is decreasing due to the high rate of deforestation compared to the rate of planting and community forest areas. Shifting attention to types of plantation and community forest wood with fast-growing wood species is one effort that can be done to overcome the limited supply of wood, especially as raw material for the wood processing industry (Karina 2003; Marsoem 2004; Subiyanto and Firmanti 2004; Alamsyah et al. 2006; Alamsyah et al. 2007; Alamsyah et al. 2008; Alamsyah et al. 2018; Alamsyah et al. 2020; Sutrisno et al. 2019). Laminated wood made from fast-growing wood is intended to meet the shortage of sawn wood supply and becomes the potential material for structural purposes. However, to make this potential successful, the study on the adhesion performance based on the wettability was done. The wettability test was performed through contact angle measurement, while the adhesion performance was expressed by strength retention (SR) and wood failure (WF) percentages through block shear tested under the Japanese Agricultural Standard (JAS).

2 Materials and methods

2.1 Materials

2.1.1 Wood species

Wood species used were Enterolobium cyclocarpum (EC), Paraserianthes falcataria (PF), Toona sinensis (TS), Gmelina arborea (GA), Pinus merkusii (PM), Acacia mangium (AM), Shorea Roxb. (S), and Acacia hybrid (AH). Detailed information about the characteristics of these wood species is presented in Table 1.

Table 1

Wood species

Species Symbol Age (year) Diameter (cm) Height (m) Density (g/cm3) MC (%)
Enterolobium cyclocarpum EC 7 28 11 0.30 9.5
Paraserianthes falcataria PF 8 30 10 0.34 9.3
Shorea sp. S n/a n/a n/a 0.47 12.0
Toona sinensis TS 11 11 10 0.49 9.0
Gmelina arborea GA 11 28 10 0.51 9.3
Pinus merkusii PM 11 23 12 0.59 9.3
Acacia mangium AM 7 31 10 0.64 9.0
Acacia hybrid AH n/a n/a n/a 0.70 12.0

MC, moisture content.

2.1.2 Adhesive types

Four types of commercial resin adhesives were used in this study. They were polyvinyl acetate emulsion (PVAc), urea formaldehyde (UF), aqueous polymer isocyanate (API), and resorcinol formaldehyde (RF). PVAc and UF are widely used in Indonesia for housing purpose and plywood production, while API and RF are commonly used for glulam production in Japan. The adhesive mixing process was carried out according to the supplier’s instructions. Detailed information about the adhesive preparation is presented in Table 2.

Table 2

Adhesives

Type Glue mixture composition (pbw) Spread rate (g/m2)
PVAc 200
UF Resin (100):NH4Cl 20% (15):flour (10) 300
API Resin (100):cross link agent (15) 250
RF Resin (100):hardener (15) 250

Pbw, parts by weight

2.2 Methods

2.2.1 Wettability measurement

A wettability test was conducted using contact-angle meter (CA-DT type A) (Kyowa Interface Co., Ltd, 1990). 60 × 20 × 5 mm specimens were cut from boards that had previously been smoothened using a planer machine. The specimens were placed on a sliding glass and conditioned at room temperature of 20°C and 65% RH for 24 h. A total of 0.20 mL distilled water (pH 5.76) was dropped onto the specimen surface at room temperature (29.5°C). Then, the contact angle was observed and measured every 10 s for 2 min of testing. The number of replications was five for each type of wood.

2.2.2 Bondability measurement

2.2.2.1 Laminated wood manufacturing

All double-layered laminates were manufactured from laminates containing heartwood and sapwood. Laminae with a size of 230 × 120 × 10 mm were smoothened using a machine planed and conditioned at a room temperature of 20°C and 65% RH for 24 h. A weighed amount of adhesive was applied to both surfaces of the laminae using a roller, followed immediately by the precise assembly. The pressure load was applied at 0.98 MPa for EC, PF, S, TS, GA, and PM laminates and at 1.18 MPa for AM and AH at a room temperature for 24 h. Before testing, laminated wood was conditioned at room temperature for 7 days.

2.2.2.2 Shear strength test

Small shear specimens were cut from double-layered laminates bonded with test adhesives. The shear strength test was carried out simultaneously with the failure test of the wood by following the JAS (2000) under normal conditions. As a comparison, the shear strength of the wood itself was also studied. Each type of the wood for each type of adhesive had a number of repetitions of 10 (a total of 320 specimens). The universal testing machine (UTM) was used in the shear strength test with a load rate of about 9.8 kN/min until failure occurs. The shear strength and strength retention were calculated using the following equations:

(1) Shear strength ( kgf/cm 2 ) = Maximum load at failure Glued area .

(2) Strength retention ( % ) = Bond shear strength Wood shear strength × 100 .

Wood failure was estimated at 0–100% of glued area. Then, bondability of the specimens was classified into four categories: excellent (80–100% both retention of strength and wood failure), good (60–79%), poor (40–59%), and very poor (0–39%) (Alamsyah et al. 2007). Specimens with excellent and good classification are indications of better adhesive penetration and easier bonding.

2.2.3 Statistical analysis

The complete randomized design of 8 × 4 (eight wood species and four adhesive types) was used to determine the significant differences between the treatments (wood species and adhesive types) and their effects on the measured parameters (contact angle, strength retention, shear strength, and wood failure). Data analysis was performed to test the difference between treatments using the Duncan test using SPSS version 16 software.

3 Results and discussion

3.1 Wettability

The measurement results of the change in the contact angle for 120 s for each type of wood are presented in Table 3 and Figure 1. The measurement values show a decrease in the contact angle over time as soon as the liquid is dropped on the measured laminae surface as presented in Table 3. In the heartwood (H) specimen, the average contact angle of the water droplet at 20 s observation time for E. cyclocarpum, P. falcataria, T. sinensis, G. arborea, P. merkusii, A. mangium, Shorea, and A. hybrid was 22, 12, 36, 83, 15, 73, 37, and 67o, respectively. In sapwood (S), the average contact angle of water droplet at 20 s observation time for E. cyclocarpum, P. falcataria, T. sinensis, G. arborea, P. merkusii, A. mangium, Shorea, and A. hybrid was 14, 6, 30, 82, 14, 61, 36, and 61°, respectively (Figure 1). Furthermore, the water droplets on the surface of E. cyclocarpum, P. falcataria, and P. merkusii were absorbed, and the contact angle was close to zero after 70 s in E. cyclocarpum, after 50 s in P. falcataria and after 60 s in P. merkusii. Conversely, on G. arborea, A. mangium, and A. hybrid, the droplets remained as the initial conditions were dropped on the laminae surface, and the contact angle had not approached zero for 2 min of observation time. Similar high contact angles for G. arborea and A. mangium have been reported by Hirabayashi and Nakano (1997). They reported that the contact angles of G. arborea and A. mangium from Malaysia were 82 and 70°, respectively, and there was no downward trend during the observation period. The lower absorption of water droplets by G. arborea, A. mangium, and A. hybrid can be attributed to the wood extractive component. It is predicted that the extractive components of G. arborea, A. mangium, and A. hybrid can cover the surface and cause surface inactivation. Extensive research shows that extractives on wood surfaces are the main physical and chemical contributors to surface inactivation, resulting in poor wettability by adhesives. This is especially true for resin species, such as southern pine and Douglas-fir. Other reasons are the most wood adhesives contain water as a carrier; therefore, they do not properly wet, flow, and penetrate the extractive covered surface. The extractive acidity of some Southeast Asian hardwood and oak species can interfere with the chemical reaction of adhesives (Bodig 1962). In contrast, the smaller contact angles for P. falcataria followed by E. cyclocarpum, P. merkusii, T. sinensis, and Shorea indicated that the surface was easier to wet compared to G. arborea, A. mangium, and A. hybrid.

Table 3

Contact angle value during measurement for 120 s

Wood species Part Elapsed time (s)
10 20 30 40 50 60 70 80 90 100 110 120
EC H 26 22 18 16 14 12 11 9 8 8 5 4
S 20 14 10 7 5 2 1 1 1 1 0 0
PF H 16 12 7 3 1 0 0 0 0 0 0 0
S 16 6 3 2 0 0 0 0 0 0 0 0
TS H 40 36 34 31 30 29 28 27 26 26 25 25
S 33 30 28 26 25 24 23 23 22 21 21 20
GA H 88 83 80 78 76 73 71 69 68 67 66 65
S 83 82 79 77 73 72 70 68 66 65 63 61
PM H 19 15 12 9 5 2 0 0 0 0 0 0
S 22 14 8 5 3 1 0 0 0 0 0 0
AM H 79 73 69 67 66 65 64 63 63 62 61 61
S 64 61 58 56 55 54 53 52 51 50 50 49
S H 41 37 36 36 35 34 32 31 30 28 26 26
S 38 36 35 34 34 33 32 31 30 28 27 25
AH H 68 67 66 64 62 60 59 59 59 58 58 58
S 62 61 60 59 57 57 56 55 54 54 54 53

H, heartwood; S, sapwood.

Figure 1 
                  Contact angle value in average.
Figure 1

Contact angle value in average.

3.2 Bondability

The results of parameter measurement of the laminated wood bonded with each adhesives type are presented in Tables 47. Among wood species used, the density values from the lowest to the highest were P. falcataria, E. cyclocarpum, Shorea, G. arborea, T. sinensis, P. merkusii, A. mangium, and A. hybrid. The density of the laminated wood bonded with API was not significantly different from UF. The density of the laminated wood bonded with RF was not significantly different from PVAc. The density of the laminated wood bonded with RF and PVAc was significantly different from the density of the laminated wood bonded with API and UF. The type of wood, the type of adhesive, and its interactions had a very significant effect on the laminated wood density. The shear strength values from the lowest to the highest were E. cyclocarpum, P. falcataria, Shorea, G. arborea, P. merkusii, A. mangium, T. sinensis, and A. hybrid. The type of wood had a very significant effect on shear strength, but the type of adhesive had no effect on its shear strength. The interaction between wood species and adhesive types had a very significant effect on the shear strength. Among wood species used, the wood failure values from the lowest to the highest were A. hybrid and A. mangium; G. arborea and P. merkusii; T. sinensis; P. falcataria, Shorea, and E. cyclocarpum. The values of wood failure of A. hybrid and A. mangium were not different, the value of wood failure of G. arborea with P. merkusii was not different, and wood failure values of P. falcataria with Shorea and E. cyclocarpum did not differ. Among adhesive types used, wood failure of the laminated wood bonded with PVAc was not significantly different from RF. Wood failure of the laminated wood bonded with API was not significantly different from UF. Wood failure of the laminated wood bonded with RF and PVAc was significantly different from wood failure of the laminated wood bonded with API and UF. Wood failure of the laminated wood bonded with RF and PVAc was lower than wood failure of the laminated wood bonded with API and UF. The type of wood species, the type of adhesive, and its interactions had a very significant effect on wood failure percentages. The strength retention value of G. arborea was not different from P. merkusii and P. falcataria. The strength retention value of P. merkusii was not different from P. falcataria and A. mangium. The strength retention value of P. falcataria was not different from A. mangium and Shorea. The strength retention value of A. mangium was not different from Shorea and A. hybrid. The strength retention value of T. sinensis was not different from E. cyclocarpum. Wood species had a very significant effect on strength retention, but the type of adhesive had no effect on strength retention. The interaction between wood species and adhesive types had a very significant effect on strength retention.

Table 4

Parameters measuring in laminated wood bonded with PVAc adhesive

Wood species Value PVAc adhesive
Density (g/cm3) Strength (MPa) Wood failure (%) Strength retention (%)
EC Average 0.39 6.27 100.00 86.89
St Dev 0.04 0.82 0.00 22.06
PF Average 0.32 7.98 100.00 77.37
St Dev 0.05 0.65 0.00 11.53
S Average 0.41 9.73 100.00 91.82
St Dev 0.04 1.85 0.00 19.72
TS Average 0.55 18.34 91.00 112.49
St Dev 0.03 3.01 9.94 19.47
GA Average 0.49 11.39 34.00 74.24
St Dev 0.01 2.91 19.55 20.05
PM Average 0.62 10.38 13.50 61.04
St Dev 0.01 0.73 7.47 9.11
AM Average 0.72 14.00 11.00 77.64
St Dev 0.03 3.28 8.10 19.03
AH Average 0.77 21.54 28.00 113.58
St Dev 0.04 3.03 22.51 16.27
Table 5

Parameters measuring in laminated wood bonded with UF adhesive

Wood species Value UF adhesive
Density (g/cm3) Strength (MPa) Wood failure (%) Strength retention (%)
EC Average 0.41 9.50 100.00 131.15
St Dev 0.02 1.23 0.00 31.16
PF Average 0.30 7.50 100.00 72.78
St Dev 0.02 0.82 0.00 12.47
S Average 0.47 8.36 100.00 78.86
St Dev 0.02 0.84 0.00 11.33
TS Average 0.50 16.33 91.00 99.90
St Dev 0.02 1.73 8.76 8.76
GA Average 0.48 12.33 62.00 81.04
St Dev 0.02 0.67 33.27 12.39
PM Average 0.61 15.86 96.00 92.79
St Dev 0.04 1.88 6.99 13.08
AM Average 0.62 15.49 64.00 86.07
St Dev 0.05 2.12 30.26 14.06
AH Average 0.72 12.48 38.00 65.82
St Dev 0.05 2.58 24.40 14.44
Table 6

Parameters measuring in laminated wood bonded with API adhesive

Wood species Value API adhesive
Density (g/cm3) Strength (MPa) Wood failure (%) Strength retention (%)
EC Average 0.32 7.25 99.00 100.73
St Dev 0.02 0.54 3.16 22.59
PF Average 0.34 9.40 98.00 90.92
St Dev 0.03 1.28 6.32 15.62
S Average 0.48 10.03 100.00 94.38
St Dev 0.02 1.23 0.00 13.43
TS Average 0.52 15.98 93.00 98.03
St Dev 0.03 2.57 6.75 15.98
GA Average 0.48 9.53 61.00 62.59
St Dev 0.02 2.77 28.07 20.35
PM Average 0.57 13.29 65.00 77.79
St Dev 0.07 3.54 30.28 21.66
AM Average 0.65 18.21 43.00 101.26
St Dev 0.06 3.04 24.97 18.96
AH Average 0.74 19.63 55.00 103.95
St Dev 0.04 3.07 33.75 19.00
Table 7

Parameters measuring in laminated wood bonded with RF adhesive

Wood species Value RF adhesive
Density (g/cm3) Strength (MPa) Wood failure (%) Strength retention (%)
EC Average 0.40 8.30 100.00 118.04
St Dev 0.04 1.86 0.00 44.28
PF Average 0.39 8.87 84.00 84.97
St Dev 0.03 1.80 26.33 14.09
S Average 0.49 9.71 89.00 90.96
St Dev 0.02 0.96 12.87 6.44
TS Average 0.52 15.44 60.00 94.65
St Dev 0.01 2.88 22.61 17.46
GA Average 0.50 11.84 62.00 77.62
St Dev 0.03 2.11 25.30 17.01
PM Average 0.55 15.14 52.00 88.20
St Dev 0.02 2.24 28.21 12.54
AM Average 0.63 13.66 22.00 75.55
St Dev 0.04 3.62 16.19 18.50
AH Average 0.76 16.56 14.00 87.61
St Dev 0.04 1.56 6.99 11.58

Furthermore, in the laminated wood bonded with PVAc (Figure 2), results show that excellent bondability was achieved by E. cyclocarpum, Shorea sp., and T. sinensis, while good bondability was achieved by P. falcataria. Poor and very poor bondability were achieved by G. arborea, P. merkusii, A. mangium, and A. hybrid. In the laminated wood bonded with UF (Figure 3), results show that excellent bondability was achieved by E. cyclocarpum, T. sinensis, and P. merkusii, while good bondability was obtained by P. falcataria, Shorea sp., A. mangium, and G. arborea. Poor bondability was achieved by A. hybrid. For the laminates bonded with API (Figure 4), results showed that excellent bondability was achieved by E. cyclocarpum, P. falcataria, Shorea, and T. sinensis, while good bondability was achieved by P. merkusii and A. mangium. Poor bondability was achieved by G. arborea and A. hybrid. Figure 5 shows that in the laminates bonded with RF, excellent bondability was achieved by E. cyclocarpum, P. falcataria, and Shorea, while good bondability was achieved by T. sinensis and G arborea. Poor bondability was achieved by P. merkusii, while very poor bondability was achieved by A. mangium and A. hybrid. In this study, the interaction between wood species and adhesive types had a very significant effect on strength retention. The results also indicated that high wettability for P. falcataria, E. cyclocarpum, P. merkusii, T. sinensis, and Shorea resulted in the better adhesive spread and more intimate contact between the wood surfaces and adhesives showing by their high strength retention with high wood failure percentages.

Figure 2 
                  Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with PVAc.
Figure 2

Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with PVAc.

Figure 3 
                  Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with UF.
Figure 3

Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with UF.

Figure 4 
                  Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with API.
Figure 4

Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with API.

Figure 5 
                  Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with RF.
Figure 5

Strength retention (SR) and wood failure (WF) percentages of the laminated wood bonded with RF.

4 Conclusion

Smaller contact angle for P. falcataria followed by E. cyclocarpum, P. merkusii, T. sinensis, and Shorea suggested that the surfaces of the wood were easier to be glued than that of G. arborea, A. mangium, and A. hybrid. It is indicated that high wettability of P. falcataria, E. cyclocarpum, P. merkusii, T. sinensis, and Shorea resulted in the better adhesive spread and more intimate contact between the wood surface and adhesive by showing their high strength retention with high wood failure percentages.

Acknowledgments

The authors wish to thank the Directorate of Research and Community Services, Ministry of Research Technology and Higher Education of the Republic of Indonesia for their financial support under the research scheme of International Research Collaborative (PKLN) of research grant No. 127/SP2H/PTNBH/DRPM/2018. The authors also would like to appreciate to PT. Sumber Graha Sejahtera in Balaraja Tangerang Indonesia for their research equipment and assistance.

  1. Funding information: This research was done under the financial support of the Directorate of Research and Community Services, Ministry of Research Technology and Higher Education of the Republic of Indonesia under the research scheme of International Research Collaborative (PKLN) of research grant No. 127/SP2H/PTNBH/DRPM/2018.

  2. Author contributions: E. M. A.: manage the implementation, control, and collect research data for the manuscript preparation; Y. S.: analysis and review data of physical characteristic of wood bonded products; S.: analysis and review of mechanical characteristic of wood bonded products; Y. H.: analysis of surface properties of wood from community forest; T. T.: analysis data of contact-angle test; M. Y.: review the manuscript before submitting.

  3. Conflict of interest: The authors state no conflict of interest.

  4. Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

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Received: 2020-09-17
Revised: 2021-01-18
Accepted: 2021-01-26
Published Online: 2021-06-11

© 2021 Eka Mulya Alamsyah et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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  37. Productivity and profitability of organic and conventional potato (Solanum tuberosum L.) production in West-Central Bhutan
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  42. Effects of soil amendments on selected soil chemical properties and productivity of tef (Eragrostis tef [Zucc.] Trotter) in the highlands of northwest Ethiopia
  43. Influence of integrated soil fertilization on the productivity and economic return of garlic (Allium sativum L.) and soil fertility in northwest Ethiopian highlands
  44. Physiological and biochemical responses of onion plants to deficit irrigation and humic acid application
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  48. Influences of spacing on yield and root size of carrot (Daucus carota L.) under ridge-furrow production
  49. Review Articles
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  51. Plantago lanceolata – An overview of its agronomically and healing valuable features
  52. Special Issue on CERNAS 2020
  53. The role of edible insects to mitigate challenges for sustainability
  54. Morphology and structure of acorn starches isolated by enzymatic and alkaline methods
  55. Evaluation of FT-Raman and FTIR-ATR spectroscopy for the quality evaluation of Lavandula spp. Honey
  56. Factors affecting eating habits and knowledge of edible flowers in different countries
  57. Ideal pH for the adsorption of metal ions Cr6+, Ni2+, Pb2+ in aqueous solution with different adsorbent materials
  58. Determination of drying kinetics, specific energy consumption, shrinkage, and colour properties of pomegranate arils submitted to microwave and convective drying
  59. Eating habits and food literacy: Study involving a sample of Portuguese adolescents
  60. Characterization of dairy sheep farms in the Serra da Estrela PDO region
  61. Development and characterization of healthy gummy jellies containing natural fruits
  62. Agro-ecological services delivered by legume cover crops grown in succession with grain corn crops in the Mediterranean region
  63. Special issue on CERNAS 2020: Message from the Editor
  64. Special Issue on ICESAT 2019
  65. Climate field schools to increase farmers’ adaptive capacity to climate change in the southern coastline of Java
  66. Special Issue on the International Conference on Agribusiness and Rural Development - IConARD 2020
  67. Supply chain efficiency of red chili based on the performance measurement system in Yogyakarta, Indonesia
  68. Sustainable value of rice farm based on economic efficiency in Yogyakarta, Indonesia
  69. Enhancing the performance of conventional coffee beans drying with low-temperature geothermal energy by applying HPHE: An experimental study
  70. Opportunities of using Spirulina platensis as homemade natural dyes for textiles
  71. Special Issue on the APA 2019 - 11th Triennial Conference
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  73. A survey on potato productivity, cultivation and management constraints in Mbala district of Northern Zambia
  74. Orange-fleshed sweetpotato: Strategies and lessons learned for achieving food security and health at scale in Sub-Saharan Africa
  75. Growth and yield of potato (Solanum tuberosum L.) as affected by storage conditions and storage duration in Jos, Plateau State, Nigeria
  76. Special Issue on the International Conference on Multidisciplinary Research - Agrarian Sciences
  77. Application of nanotechnologies along the food supply chain
  78. Special Issue on Agriculture, Climate Change, Information Technology, Food and Animal (ACIFAS 2020)
  79. The use of endophytic growth-promoting bacteria to alleviate salinity impact and enhance the chlorophyll, N uptake, and growth of rice seedling
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