Backstepping and Sliding-Mode Methods for Stabilizing an Underactuated X4-AUV

In this paper, we are interested principally in dynamic modelling of an autonomous underwater vehicle (X4-AUV) while taking into account the high order nonholonomic constraints in order to develop a new control scheme as well as the various physical phenomena, which can influence the dynamic of a swimming structure. We deal with the design of two controllers, based on backstepping and sliding-mode control techniques to stabilize altitude and attitude of an underactuated X4-AUV. The designed controllers are: full backstepping control for attitude and altitude control, and partially slidingmode control for attitude combine with altitude backstepping control. Some numerical simulations are conducted to demonstrate the effectiveness of the proposed controllers

Efficiency of edible coating chitosan and cinnamic acid to prolong the shelf life of tomatoes

Tomato (Solanum lycopersicum L.) is a large target commodity for Malaysia’s export trade. However, tomato is a perishable climacteric fruit that requires favourable conditions to maintain its freshness from farm to the table. Its fast ageing process tends to attract pathogens that reduce the shelf life of a detached tomato, hence affecting its quality causing severe losses to the agropreneurs (Anderson et al., 2014). Therefore, there is a dire need for a mechanism to maintain the freshness of tomatoes. This study aims to examine the effects of chitosan and cinnamic acid as edible coatings to prolong the shelf life of tomatoes. Chitosan plays a role as an antifungal agent whereas cinnamic acid possesses antimicrobial properties that help to improve the shelf life of tomatoes (Bautista-Baños et al. (2006). In the study, Chitosan and cinnamic acid coatings were applied on fresh graded tomatoes at two maturity stages; breakers and turning. The samples were observed every three days for a total period of 12 days at ambient temperature. The results showed that a single coating of chitosan (0.5 %) had a positive impact on the total soluble solids (TSS), firmness, hue angle and weight loss of the samples. On the other hand, cinnamic acid (2mM) influenced the firmness, weight loss and TSS value of the tomatoes. The coatings inhibit respiration and minimise starch conversion into sugar that could lead to lowered sugar (TSS) content. The restriction on respiration ensures firmness and delay the colour change of fruits at a particular period. The slowing of the ripening process that causes ageing and weight loss in fruits is reduced. Both coatings were proven to be highly feasible for application in various industries due to their edible, non-toxic and biodegradable nature

Response of growth performance and yield of butternut squash(Cucurbita moschata Duch Ex Poir) cultivar Waltham under differentdosages of bokashi application

 Butternut squash, also known as Cucurbita moschata, is a variety of pumpkin with promising commercial potential. However,most of the soils in the tropics are acidic and lack organic matter.The addition of organic material such as bokashi is essential inimproving the low soil pH and soil quality. Therefore, this study aimed to elucidate the effects of different rates of bokashi application on the growth performance and yield of butternut squash cultivated on tropical acid soil. A planting experiment was carried out from July until October 2022. A total of 36 planting beds were prepared, and each bed was constructed in 100 cm x 400 cm, consisting of 8 plants bed-1. The experiment was arranged in a Randomized Complete Block design. A total of three different rates of bokashi were applied to the soil prior to planting, namely 0 (control), 4,000, and 8,000 kg ha-1. A 12,000 kg ha-1 of commercial peat moss (Holland Free Peat) was also applied to compare bokashi and peat moss (the common planting medium used in most planting activities). The maximum plant height growth and leaf production for butternut squash was around 7-8th week. Application rate of 8,000 kg ha-1 bokashi contributed to significantly highest plant height (352.1 cm), number of leaves (86 leaves), and yield of Waltham butter squash per plant (1.5 kg plant-1). Multiple planting cycles should be carried out further to elucidate the bokashi's residual effect on nutrient supply to butternut squash cultivation

Youths Participation on Development of Entrepreneurship Agricultural Fresh Produce Preservation Skill Training Module

Agriculture product preservation can prevent the dumping of waste of fresh produce and also can increase the agriculture entrepreneurship for country development. Most of youth have unemployment problems especially after completing their studies because lack of skills and experience. Through this skill training module, it helps youth to build another career that can help them in future which is involving in agriculture entrepreneurship. This study was developed skill training module to attract youth that want to venture into agriculture product preservation business. A total of 30 respondents in University Malaysia Kelantan, Jeli Campus were joined the training where a developed questionnaire was used to gain the data at the end of the training. For analysis, the descriptive analysis was employed by using SPSS software. Based on the results, all of the respondents gave positive feedback towards this training and many of them interested to join this field of business to improve the quality of life in the future.

Effect of bean sprout on in vitro multiplication of Musa acuminata

Musa acuminata or Pisang Berangan is popular in Kelantan, but due to a lack of knowledge on modern farming technologies, many Musa acuminata are affected by diseases and are of low quality. Plant tissue culture has numerous advantages, including a rapid rate of multiplication, and the prevention of disease. Plant growth regulator such as Benzyl Amino Purine (BAP) is commonly used in media to grow banana explants, however, Murashige and Skoog (MS) media production with BAP hormone is expensive for low-income farmers. Therefore, this research had been done by substituting the BAP hormone by using bean sprout extract as an organic supplement for banana culture. The additives that were used in this project were non-centrifuged and centrifuged bean sprout extracts at different concentrations, which were 5%, 10%, 15% and 20% applied in the MS media. Data were collected based on number of leaves, length of leaves and length of roots. In this study, the positive control treatment with MS + 5 mg/L BAP media recorded the highest mean value in the number of leaves, length of leaves, and length of roots with values of 12.5 ± 0.59, 5.69 ± 0.13cm, and 6.45 ± 0.36cm respectively followed by MS media with centrifuged bean sprout extract. From the observation, the bean sprout has the potential to use as an additive for Musa acuminata media to substitute synthetic hormones such as BAP

Backstepping and sliding-mode methods for stabilizing an underactuated X4-AUV

In this paper, we are interested principally in dynamic modelling of an autonomous underwater vehicle (X4-AUV) while taking into account the high order nonholonomic constraints in order to develop a new control scheme as well as the various physical phenomena, which can influence the dynamic of a swimming structure. We deal with the design of two controllers, based on backstepping and sliding-mode control techniques to stabilize altitude and attitude of an underactuated X4-AUV. The designed controllers are: full backstepping control for attitude and altitude control, and partially slidingmode control for attitude combine with altitude backstepping control. Some numerical simulations are conducted to demonstrate the effectiveness of the proposed controllers

Herbicidal activity of pre and post emergent herbicide on control eleusine indica in aerobic rice system

Aerobic rice system can be an alternate way to cultivate rice in less water conditions. However, weeds are a major constrain in aerobic rice field which decline its success. Weeds are being controlled by herbicides in aerobic rice but not all herbicides are effective in controlling various types of weeds. In this study, two pre-emergent (pretilachor and pendimethalin) and two post-emergent (cyhalofop-butyl and bispyribac-sodium) herbicides were evaluated for effective control of the bioassay species, Eleusine indica. It was found that pendimethalin at a higher application rate of 1.0 kg ai ha⁻¹ strongly inhibit the emergence and shoot growth of E. indica by >75% with negligible effect on the rice growth with stimulation on the leaf greenness. Conversely, pretilachor, cyhalofop-butyl and bispyribac-sodium gave moderate inhibition (55-60% inhibition) on weed emergence and shoot growth at higher application rates of 0.44, 0.1 and 0.035 kg ai ha⁻¹, respectively. Significant inhibitory effects on rice root growth were noticed at highest application rates of pretilachor, cyhalofop-butyl and bispyribac-sodium (40-50% inhibition) across the growth stage of rice seedlings. Great reduction in shoot height, shoot fresh weight, and greenness of rice plant also was evident at 0 DAS across herbicides rates. However, with increasing growth stages, the rice plant became less susceptible to the applied treatments. The finding suggested that pendimethalin at 1.0 kg ai ha⁻¹ was the most suitable application rate for inhibiting E. indica without injuring the rice seedlings

Phytotoxic activity of oil palm frond mulch in combination with selected preemergence herbicide

The combination of mulch and herbicide is a promising method for weed control which could reduce the frequency of hand weeding. This study was conducted to evaluate the phytotoxic effects of Elaeis guneensis var. tenera (oil palm) frond (OPF) mulch in combination with several pre emergence herbicides on the inhibition of goosegrass (Eleusine indica (L.) Gaertn), slender cyperus (Cyperus distans L.f.) and coat buttons (Tridax procumbens (L.)) under greenhouse conditions. Three rates of dinoterb, oxyfluorfen, and isoxaflutole were respectively, applied with or without OPF mulch at 3.5 t ha−1. The results showed that the weed inhibition provided by the dinoterb-treated OPF mulch (60 to 100%) was greater than dinoterb (0 to 50%) or OPF mulch (0 to 60%) applied alone across all the application rates and bioassay species. The oxyfluorfen-treated OPF mulch also gave greater inhibition (70 to 90%) of T. procumbens than those provided by oxyfluorfen (20 to 40%) or the OPF mulch alone (55 to 60%). However, an increase in inhibition of C. distans and E. indica was only evident at a low rate of oxyfluorfen when combined the OPF mulch. Weed inhibition was noted with increasing rates of isoxaflutole alone but the isoxaflutole-treated OPF mulch did not lead to further inhibition of weeds except for T. procumbens. These results suggest that the phytotoxicity of OPF mulch in combination with herbicides are dependent on weed species, herbicides, and application rates, with dinoterb being the most compatible with OPF mulch when combine

Cellulase enzyme production from filamentous fungi trichoderma reesei and aspergillus awamori in submerged fermentation with rice straw

Fungi are a diverse group of microorganisms that play many roles in human livelihoods. However, the isolation of potential fungal species is the key factor to their utilization in different sectors, including the enzyme industry. Hence, in this study, we used two different fungal repositories—soil and weed leaves—to isolate filamentous fungi and evaluate their potential to produce the cellulase enzyme. The fungal strains were isolated using dichloran rose bengal agar (DRBA) and potato dextrose agar (PDA). For cellulase enzyme production, a rice straw submerged fermentation process was used. The enzyme production was carried out at the different incubation times of 3, 5, and 7 days of culture in submerged conditions with rice straw. Fungal identification studies by morphological and molecular methods showed that the soil colonies matched with Trichoderma reesei, and the weed leaf colonies matched with Aspergillus awamori. These species were coded as T. reesei UMK04 and A. awamori UMK02, respectively. This is the first report of A. awamori UMK02 isolation in Malaysian agriculture. The results of cellulase production using the two fungi incorporated with rice straw submerged fermentation showed that T. reesei produced a higher amount of cellulase at Day 5 (27.04 U/mg of dry weight) as compared with A. awamori (15.19 U/mg of dry weight), and the concentration was significantly different (p < 0.05). Our results imply that T. reesei can be utilized for cellulase production using rice straw