The formation of self-assembled monolayers on surfaces is often likely to be accompanied by the formation of byproducts, whose identification holds clues to the reaction mechanism but is difficult due to the minute amounts produced. We now report a successful identification of self-assembly byproducts using gold aerogel with a large specific surface area, a procedure likely to be applicable generally. Like a thin gold layer on a flat substrate, the aerogel surface is alkylated with n-butyl-d9 groups upon treatment with a solution of tetra-n-butylstannane-d36 under ambient conditions. The reaction byproducts accumulate in the mother liquor in amounts sufficient for GC-MS analysis. In chloroform solvent, they are butene-d8, butane-d10, octane-d18, and tributylchlorostannane-d27. In hexane, they are the same except that tributylchlorostannane-d27 is replaced with hexabutyldistannane-d54. The results are compatible with an initial homolytic dissociation of a C-Sn bond on the gold surface, followed by known radical processes.

Previous studies have shown favourable properties for papaya bast fibres, with a Young's modulus of up to 10 GPa and a tensile strength of up to 100 MPa. Because the fibres remain as residues on papaya plantations across the tropics in large quantities, their use in the making of green composites would seem to be worthy of consideration. This study aims to show that such composites can have very suitable mechanical properties, comparable to or even better than the common wood plastic composites (WPCs), and as such, represent a promising raw material for composites and a low-cost alternative to wood.

Previous studies have shown favourable properties for papaya bast fibres, with a Young's modulus of up to 10 GPa and a tensile strength of up to 100 MPa. Because the fibres remain as residues on papaya plantations across the tropics in large quantities, their use in the making of green composites would seem to be worthy of consideration. This study aims to show that such composites can have very suitable mechanical properties, comparable to or even better than the common wood plastic composites (WPCs), and as such, represent a promising raw material for composites and a low-cost alternative to wood.

An Giang province is one of the largest rice producer regions in Vietnam with 600,000 hectares of paddy field and 4 million tons of rice production every year. The rice milling industry generates a huge amount of rice husk (~23% of paddy rice). The rice husk is currently used as fuel around the province generating rice husk ash (RHA) which causes environmental and health issues. This study focuses on surveying and analyzing the current situation for utilization, management, treatment, and awareness of enterprises and community about generated RHA via a household investigation method. The results showed that, in average, a factory generates 862.4 tons of RHA per year, whereas half of them are reused or are sold for re-utilization in other factories, 56.3% are disposed in the private landfill of the factory, and 1.6 to 6.3 % are directly disposed to nearby rivers or in soil. Most of the interviewed citizens reported that they were aware of the RHA impact on the environment nevertheless, only 2% knew that RHA can be re-utilized for other purposes. Therefore, it is necessary to raise public awareness about the reuse and utilization of RHA to reduce the environmental impact and contribute to the sustainable development of the rice production. / Tỉnh An Giang là một trong những vựa lúa lớn nhất Việt Nam, với diện tích khoảng 600.000 ha và sản lượng gần 4 triệu tấn/năm. Cùng với lúa, lượng trấu phát sinh từ quá trình xay xát đang được tái sử dụng làm nhiên liệu đốt cho các quá trình sản xuất khác ở địa phương. Tuy nhiên lượng tro sau quá trình đốt nhiên liệu trấu cũng đang tạo nên một áp lực lên chất lượng môi trường. Do vậy, nghiên cứu này tập trung vào việc khảo sát và phân tích hiện trạng sử dụng, quản lý, xử lý và nhận thức của cơ sở sản xuất hay cộng đồng đối với vấn đề phát thải tro trấu thông qua phương pháp điều tra thực tế. Kết quả cho thấy trung bình mỗi cơ sở phát sinh 862,4 tấn tro trấu/năm với khoảng phân nửa trong số đó được tái sử dụng, 56,3% xử lý bằng cách chôn lấp; 1,6% đến 6,3% xử lý bằng cách đổ bỏ. Hầu hết những người được phỏng vấn biết việc phát thải tro trấu có ảnh hưởng đến chất lượng môi trường, tuy nhiên chỉ có 2% hộ nhận thức được tro trấu có thể tái sử dụng cho các mục đích khác. Điều này cho thấy cần có biện pháp nâng cao nhận thức của cộng đồng đối với việc tái sử dụng tro trấu, nhằm góp phần giảm áp lực của phát thải lên môi trường và đóng góp vào sự phát triển của ngành sản xuất lúa gạo theo định hướng bền vững.

Durch die Nutzung des fischfutterbedingten Nährstoffeintrags für die kombinierte Produktion von Fischen und Pflanzen können Aquaponiksysteme eine nachhaltige Erweiterung von Kreislaufanlagen der Aquakultur (RAS) darstellen. Herkömmliche Aquakulturfutter zielen jedoch auf Fischproduktion mit geringer Umweltbelastung ab und sind somit nicht für die Aquaponik optimiert. Daher weist RAS-Wasser häufig Mängel im Profil gelöster anorganischer Pflanzennährstoffe auf. So war es Ziel dieser Arbeit, die Auswirkungen unterschiedlicher Proteinquellen auf die Nährstoffdynamik in RAS durch Fütterungsversuche mit Afrikanischem Raubwels und Nil-Tilapia zu untersuchen, bei denen Wachstum, gelöste anorganische Nährstoffkonzentrationen im RAS-Wasser und die Ausscheidung von Nährstoffen über den Kot verfolgt wurden. Der Fokus lag auf nachhaltigen alternativen Proteinquellen zu marinem Fischmehl und terrestrischen Pflanzenproteinen: Larvenmehl der Schwarzen Soldatenfliege (BSFM), Welsschlachtabfallmehl (CM), Geflügelschlachtabfallmehl (PM) und Geflügelblutmehl (PBM). Experimentalfutter, die phosphorreiches PM und CM enthielten, förderten erhöhte Ausscheidung von löslichem reaktivem Phosphor, erzeugten die besten gelösten N:P-Verhältnisse im RAS-Wasser verglichen mit einer Hydroponik-Nährlösung und ermöglichten in Kombination mit PBM besseres Wachstum beim Wels als ein vergleichbares kommerzielles Futter. In Futtern basierend auf einer einzigen Proteinquelle führte PM bei Wels und insbesondere bei Tilapia zu ähnlichem Wachstum verglichen mit marinem Fischmehl, wohingegen BSFM und PBM bei beiden Arten Wachstumsleistung beeinträchtigte. Meta-Analysen aller Versuche legen nahe, dass höherer Phosphor-, Kalium- und Magnesiumgehalt im Futter erhöhte Ausscheidung dieser Elemente in gelöster Form bedingt, was sie zu Zielnährstoffen in Aquaponikfuttern macht, während die Optimierung des Protein zu Energie-Verhältnisses im Futter die gelösten N:P- und N:K-Verhältnisse im RAS-Wasser verbessern kann. / By using the nutrient input from fish feeds for the combined production of fish and plants, aquaponic systems can be a sustainable extension of recirculating aquaculture systems (RAS). However, conventional aquaculture feeds are optimized for fish production and reduced environmental impact rather than aquaponics. Hence, RAS water is often characterized by deficiencies regarding its dissolved inorganic plant nutrient profile. Therefore, this thesis aimed to explore the effect of purposeful dietary protein choice on nutrient dynamics in RAS through four systematic feeding trials involving African catfish and Nile tilapia in which growth performance, dissolved inorganic nutrient concentrations in RAS water and solid fecal nutrient excretion were tracked. Focus was on sustainable alternative protein sources to marine fish meal and terrestrial plant proteins: black soldier fly larvae meal (BSFM), catfish by-product meal (CM), poultry by-product meal (PM) and poultry blood meal (PBM). Experimental diets including phosphorus-rich PM and CM supported increased excretion of soluble reactive phosphorus, produced the most favorable dissolved N:P ratios in RAS water when compared to a renowned hydroponic nutrient solution, and, combined with PBM, enabled better growth performance in African catfish than a comparable commercial diet. In single protein source diets, PM produced similar growth performance in African catfish and particularly Nile tilapia versus marine fish meal, whereas BSFM and PBM impaired growth performance in both species. Meta-analyses covering all trials suggest that higher dietary phosphorus, potassium and magnesium content leads to their increased excretion in dissolved form, making them target nutrients for aquaponic feed formulation, while the optimization of the dietary protein to energy ratio can further improve dissolved N:P and N:K ratios in RAS water.