Modelling the Extraction of Pectin towards the Valorisation of Watermelon Rind Waste

Watermelon is the second largest fruit crop worldwide, with great potential to valorise its rind waste. An experimental design was used to model how extraction parameters (temperature, pH, and time) impact on the efficiency of the process, purity, esterification degree, monosaccharide composition and molar mass of watermelon rind pectin (WRP), with an insight on changes in their structural properties (linearity, branching degree and extraction severity). The models for all responses were accurately fitted (R2 > 90%, lack of fit p ≥ 0.05) and experimentally validated. At optimum yield conditions, WRP yield (13.4%), purity (540 µg/g galacturonic acid) and molar mass (106.1 kDa) were comparable to traditional pectin sources but showed a higher branching degree with longer galactan side chains and a higher protein interaction. Harsher conditions (pH 1) generated purer homogalacturonan fractions with average molar masses (80 kDa) at the expense of yield, while mild extraction conditions (pH ≥ 2) produced highly branched entangled pectin structures. This study underlines novel compositional features in WRP and the possibility of producing novel customized pectin ingredients with a wider potential application scope depending on the targeted structure.

Grapevine nitrogen metabolism as a function of crop load using a 15N-labelling approach

<p>This presentation addresses the actual concerns in viticulture regarding grapevine nitrogen (N) metabolism in the context of reducing both inputs and environmental pollution, while optimizing the balance between yield and wine quality. By adapting agronomical practices to the environmental conditions (i.e. soil and climate), it is possible to optimise both plant N use efficiency (NUE) and crop quality, while reducing N input in the vineyard. The present trial demonstrates the potential of crop-load limiting (via bunch thinning) to fine-tune plant NUE and optimise grape N composition at harvest. These results improve the comprehension of the seasonal plant N cycle in perennial crops and it contributes to the implementation of sustainable practices in vineyards and potentially in other crops.</p><p>Over the past decades, N supply in vineyards has been reduced with the aim of adjusting vigour and yield. Moreover, the development of cover cropping has led to increased competition for N resources in vineyards, which can, in some cases, be detrimental to both yield and quality of the crop. This evolution of management practices – without considering the environmental conditions – has led to situations with major grape N deficiencies, being detrimental to fermentation kinetics, yield and possibly wine quality. Given the major role of N in plant physiology, an integrative approach to managing grapevine N nutrition from soil to crop – in accordance with the environmental conditions – represents a sustainable solution for high-quality grape production.</p><p>In this trial on white cv. Chasselas (Vitis vinifera L.), plant N partitioning and grape composition were monitored over two years, in relation to both crop load and fertilisation. These aims were accomplished by testing a large crop load gradient (via bunch thinning, resulting in 0.7–5.2 kg per plant) and by using a <sup>15</sup>N-labelling method (fertilization with 10 atom % <sup>15</sup>N foliar urea). The results indicate that the mobilisation of root N reserves plays a major role in the balance of fruit N content. Carry-over effects to the next year were highlighted. N uptake and assimilation appeared to be strongly stimulated by high-yield conditions. Fertilisation largely contributed to fulfilling the high fruit N demand while limiting the mobilisation of root N reserves under high-yield conditions. Plants were able to modulate both root N reserve mobilisation and N uptake as a function of crop load, thus maintaining a relatively uniform N concentration in fruits. However, the fruit free amino N profile was modified, which potentially affected aromas in grapes and wines. A modelling of the seasonal plant N cycle (i.e. uptake and efflux) is also proposed.</p><p><strong>Key words</strong>: Nitrogen metabolism, <sup>15</sup>N-isotope labelling, crop load, grape composition, wine quality</p>

RESEARCH ON THE BEHAVIOR OF AN ASSORTMENT OF BELL PEPPER ON THE SANDY SOILS IN SOUTH-WEST OLTENIA ACCORDING TO THE CULTIVATION METHOD USED

The pedo-climatic conditions specific to sandy soils in southwest Oltenia determine differences in performing different phenophases of growth and development of plants, both between varieties and in the physiological behavior of the same variety under different yield conditions. Therefore, at the Dăbuleni Research and Development Station for Plant Culture on Sands, research was carried out on some physiological, biochemical and production processes at five varieties of bell peppers cultivated in the open fields and solar. Determinations of photosynthesis, foliar transpiration, the biochemical composition of fruits, quantity, and quality of bell pepper production were performed. The physiological and biochemical processes studied were influenced by the environmental conditions specific to each cultivation method, but also by the studied variables. Of the 5 varieties studied, the best results on the biochemical composition of the fruits were recorded at the Artim variety (8.83% total dry substance, 4.60% soluble dry substance, 0.19% acidity, 3.80% carbohydrate and 36.96% vitamin C). The production was between 15,387 t / ha for open-field plants and 108,574 t / ha for plants grown in the solar, the differences between the two cultivation methods being statistically assured as distinctly significant.

Limits to elastic response. Yielding and failure

This chapter presents conditions for determining the limits of elastic behaviour for isotropic materials. The stress invariants of equivalent pressure, equivalent shear stress, and equivalent tensile stress are defined. These are then used to define common yield conditions, viz. the pressure-independent Mises and Tresca yield conditions, as well as the pressure-dependent Coulomb-Mohr and the Drucker-Prager yield conditions. Rankine’s failure criterion for brittle materials in tension, that is failure in a brittle material will initiate when the maximum principal stress at a point in the body reaches a critical value, is also discussed.

ANALISIS REGANGAN BAJA TULANGAN PADA STRUKTUR PILE CAP EMPAT TIANG METODE STRUT AND TIE MODEL

ABSTRACTPile cap is one of the many types of structures that are entirely Disturbed-region. The structure undergoes a non-linear strain because it was meeting point of the pile and column with centralized forces. In addition, geometry changes occur at the meeting between the column, pile cap, and pile, so the Bernoulli concept is no longer suitable for this condition. Pile cap testing consists of two groups of specimens and each group consists of three specimens. The first group was designed using the STM method (SNI 2847: 2013 Appendix A) and the second group was designed using conventional methods (SNI 2847: 2013 Article 15). Loading is the application of a centralized static load that is channeled through a centric column until the pile cap structure has collapsed. The results show that: (1) The flexural reinforcement which experiences the first yield condition both on the pile cap testing of the STM method and in the conventional method was the X direction flexural reinforcement (outsidest flexural reinforcement). (2) The average strain of the yield conditions and load on the pile cap STM method were 2242 με and 528.97 kN, whereas the conventional method were 2436 με and 437.03 kN. (3) Increasing the load capacity of the yield conditions (Py) of the pile cap STM method and conventional method on the plan load (Pn) were 32.2% and 9.3%.Keywords: pile cap, four piles, Strut and Tie Model (STM) ABSTRAK Pile cap merupakan salah satu dari jenis struktur yang sepenuhnya merupakan daerah terganggu (Disturbed-region). Struktur tersebut mengalami regangan non-linear karena merupakan titik pertemuan pile dan kolom dengan gaya-gaya terpusat. Selain itu, terjadi perubahan geometri pada pertemuan antara kolom, pile cap, dan pile, sehingga konsep Bernoulli tidak cocok lagi pada kondisi tersebut. Pengujian pile cap terdiri dari dua kelompok benda uji dan masing-masing kelompok terdiri dari tiga buah benda uji. Kelompok pertama dirancang menggunakan metode STM (SNI 2847:2013 Lampiran A) dan kelompok kedua dirancang menggunakan metode konvensional (SNI 2847:2013 Pasal 15). Pembebanan berupa penerapan beban statik terpusat yang disalurkan melalui kolom sentris sampai struktur pile cap mengalami keruntuhan. Hasil menunjukkan bahwa: (1) Tulangan lentur yang mengalami kondisi leleh terlebih dahulu baik pada pengujian benda uji pile cap metode STM maupun pada metode konvensional adalah tulangan lentur arah X (tulangan lentur terluar). (2) Rata-rata regangan kondisi leleh dan beban pada benda uji pile cap metode STM adalah 2242 με dan 528,97 kN, sedangkan pada metode konvensional adalah 2436 με dan 437,03 kN . (3) Peningkatan kapasitas beban kondisi leleh (Py) pada benda uji pile cap metode STM dan metode konvensional terhadap beban rencana (Pn) adalah 32,2 % dan 9,3 %. Kata kunci: pile cap, empat tiang, Strut-and-Tie Model (STM)

Elastoplastic Deformation in an Orthotropic Spherical Shell Subjected to a Temperature Gradient

The objective of this research paper is to present the study of elastoplastic deformation in an orthotropic spherical shell subjected to a temperature gradient by using Seth’s transition theory. Seth’s transition theory includes classical macroscopic solving problems in plasticity, creep and relaxation and assumes semi-empirical yield conditions. The nonlinear transition regions through which yielding occurs are neglected. Apparently, transition theory is used to solve problems in a general way, employing the concept of generalized strain measure and asymptotic solution at the transition points of differential equations. The problems of elastoplastic and creep transitions are solved through principal stress and principal stress difference and in consideration of the nonlinear part of the transition.