A first-principles study of helium storage in oxides and at oxide--iron interfaces

Density-functional theory calculations based on conventional as well as hybrid exchange-correlation functionals have been carried out to study the properties of helium in various oxides (Al2O3, TiO2, Y2O3, YAP, YAG, YAM, MgO, CaO, BaO, SrO) as well as at oxide-iron interfaces. Helium interstitials in bulk oxides are shown to be energetically more favorable than substitutional helium, yet helium binds to existing vacancies. The solubility of He in oxides is systematically higher than in iron and scales with the free volume at the interstitial site nearly independently of the chemical composition of the oxide. In most oxides He migration is significantly slower and He--He binding is much weaker than in iron. To quantify the solubility of helium at oxide-iron interfaces two prototypical systems are considered (Fe|MgO, Fe|FeO|MgO). In both cases the He solubility is markedly enhanced in the interface compared to either of the bulk phases. The results of the calculations allow to construct a schematic energy landscape for He interstitials in iron. The implications of these results are discussed in the context of helium sequestration in oxide dispersion strengthened steels, including the effects of interfaces and lattice strain.Comment: 13 pages, 10 figures, 4 table

Pengolahan Air Limbah Dometsik dengan Metode Kombinasi Filtrasi dan Fitoremediasi (Studi Kasus Di Kelurahan Margorejo Surabaya)

Limbah domestik (grey water) di wilayah Margorejo Sawah Surabaya yang terbuang pada saluran drainase disaat musim kemarau terkumpul pada wilayah terendah dan menjadi tampungan akhir, dari tampungan ini tidak dapat terbuang ke berbagai arah sehingga menjadikan kumpulan limbah yang cukup bahaya dengan dicirikan warna air kehitaman dan bahkan beberapa jenis ikan seperti nila dan lele pada mati dalam beberapa jam setelah ditebar pada saluran drainase, sehingga perlu adanya pengolahan fisik dan biologis. Tujuan dalam penelitian ini untuk menganalisis kemampuan penurunan konsentrasi air limbah dari saluran drainase dengan media filtrasi pasir silika dan karbon aktif. Analisis kualitas air limbah di saluran drainase cukup buruk dengan konsentrasi cukup tinggi sebesar 800,18 mg/L untuk BOD; 1.653,92 mg/L untuk COD dan 432 mg/L untuk TSS. Penurunan konsentrasi air limbah dengan media filtrasi pasir silica dan karbon aktif memenuhi baku mutu pada hari ke 9 dengan konsetrasi baku mutu COD sebesar 100 mg/L; BOD sebesar 30 mg/L dan TSS sebesar 30 mg/L

Flavour components of some processed. fish and fishery products of Japan

A study was conducted to examine the flavour components of some processed fish and fishery products of Japan by gas chromatography-mass spectrometry (GC-MS). In brief the method was to absorb the headspace volatiles at 70°C into the fused silica fibre of needle of the solid phase micro extraction fibre. The absorbed components were injected to the GC-MS. The components were identified by computer matching with library database as well as by authentic standard components. In general the number of flavour components were higher in the processed fish and fishery products (except frozen prawn) than that of the raw fish and prawn. The concentration (quantity) of the f1avour components in processed fish and fishery products was much higher than that of the raw fish and prawn. Smoked salmon and baked salmon possessed double number of flavour components than that of the raw salmon. Smoking resulted the highest number of flavour components followed by baking (grilling) and canning, surimi products (kamaboko and chikuwa), drying and lastly salting. However, freezing and frozen storage resulted loss of flavour components in prawn

A Comparative Study for Different Sizing of Solar PV System under Net Energy Metering Scheme at University Buildings

Malaysia has moved forward by promoting the use of renewable energy such as solar PV to the public to reduce dependency on fossil fuel-based energy resources. Due to the concern on high electricity bill, Universiti Malaysia Perlis (UniMAP) is keen to install solar PV system as an initiative for energy saving program to its buildings. The objective of this paper is to technically and economically evaluate the different sizing of solar PV system for university buildings under the Net Energy Metering (NEM) scheme. The study involves gathering of solar energy resource information, daily load profile of the buildings, sizing PV array together with grid-connected inverters and the simulation of the designed system using PVsyst software. Based on the results obtained, the amount of solar energy generated and used by the load per year is between 5.10% and 20.20% from the total annual load demand. Almost all solar energy generated from the system will be self-consumed by the loads. In terms of profit gained, the university could reduce its electricity bill approximately between a quarter to one million ringgit per annum depending on the sizing capacity. Beneficially, the university could contribute to the environmental conservation by avoiding up to 2,000 tons of CO2 emission per year

Combustion synthesis of chromium nitrides

This paper explores different modes of synthesis by combustion of chromium-nitrogen and ferrochromium-nitrogen alloys. The SH-synthesis of chromium nitrides and ferrochromium nitrides was performed. Regular patterns in layer-by-layer and surface modes of Cr combustion in nitrogen were investigated. The mechanism of non-stationary combustion during the synthesis of chromium was investigated. Regular patterns of chromium and ferrochromium combustion in the cocurrent filtration mode were analyzed, and the possibility to intensify the SHS process using the pressure filtration principle was assessed. The process of chromium powder combustion in the cocurrent flow of nitrogen-containing gas in the range of specific flow rates from 20 cm3/s·cm2 was investigated. Pressure filtration intensifies the process of combustion wave propagation in the Cr–N2 system. Here, the combustion rate increases while the degree of nitridation decreases. We discovered superadiabatic heating modes when the reaction zone was blown with pure nitrogen and a nitrogen-argon mixture. The tempering mode that was realized during pressure filtration allows for the uptake of high-temperature single-phase non-stoichiometric phases of Cr2N

Mechanical Behavior of Nanostructured Hybrids Based on Poly(Vinyl Alcohol)/Bioactive Glass Reinforced with Functionalized Carbon Nanotubes

This study reports the synthesis and characterization of novel tridimensional porous hybrids based on PVA combined with bioactive glass and reinforced by chemically functionalized carbon nanotubes (CNT) for potential use in bone tissue engineering. The functionalization of CNT was performed by introducing carboxylic groups in multiwall nanotubes. This process aimed at enhancing the affinity of CNTs with the water-soluble PVA polymer derived by the hydrogen bonds formed among alcohol (PVA) and carboxylic groups (CNT–COOH). In the sequence, the CNT–COOH (0.25 wt%) were used as the nanostructure modifier for the hybrid system based on PVA associated with the bioactive glass (BaG). The mechanical properties of the nanostructured hybrids reinforced with CNT–COOH were evaluated by axial compression tests, and they were compared to reference hybrid. The averaged yield stresses of macroporous hybrids were (2.3 ± 0.9) and (4.4 ± 1.0) MPa for the reference and the CNT reinforced materials, respectively. Moreover, yield strain and Young's modulus were significantly enhanced by about 30% for the CNT–COOH hybrids. Hence, as far as the mechanical properties are concerned, the results have clearly showed the feasibility of utilizing these new hybrids reinforced with functionalized CNT in repairing cancellous bone tissues

Pengembangan Formula Minuman Olahraga Berbasis Tempe untuk Pemulihan Kerusakan Otot

Penelitian ini bertujuan untuk mempelajari formulasi minuman olahraga berbasis tempe untuk pemulihan kerusakan otot dengan kandungan gizi yang tepat dan dapat diterima secara sensori. Penelitian ini menggunakan rancangan acak lengkap dengan faktor tunggal yaitu jumlah penambahan air untuk melarutkan tepung tempe yang terdiri dari tiga tingkatan yaitu 500 ml, 600 ml dan 700 ml, dengan masing-masing perlakuan mengandung 23 gram protein. Tepung tempe yang digunakan mengandung kadar air 5,39%, abu 1,22 % berat kering, protein 45,55% berat kering, lemak 33,9% berat kering, karbohidrat 13,94 % berat kering, kalsium 0,14% berat kering, besi 0,018% berat kering, natrium 0,004% berat kering, magnesium 0,06% berat kering, klorida 0,04% berat kering dan kalium 0,10% berat kering. Hasil uji hedonik minuman tempe menunjukkan bahwa penambahan air 600 ml cenderung mempunyai nilai kesukaan secara keseluruhan yang paling tinggi (5,42) dibandingkan dengan penambahan air 700 ml (5,37) dan 500 ml (nilai 4,92) (P>0,05). Minuman tempe dengan penggunaan air 600 ml mempunyai penerimaan secara keseluruhan yang tertinggi dengan nilai 80%. Minuman tersebut mempunyai karakteristik per sajian sebagai berikut kandungan protein 23 gram, karbohidrat 48 gram, lemak 17,11 gram, energi 438 kkal, branched chain amino acids (BCAA) 4161,6 mg, Ca 72,92 mg, Fe 9,46 mg, Mg 33,12 mg, Na 2,37 mg dan Cl 21,30 mg, dan K 54 mg

A Closer Look at Solar Wind Sputtering of Lunar Surface Materials

Solar-wind induced potential sputtering of the lunar surface may be a more efficient erosive mechanism than the "standard" kinetic (or physical) sputtering. This is partly based on new but limited laboratory measurements which show marked enhancements in the sputter yields of slow-moving, highly-charged ions impacting oxides. The enhancements seen in the laboratory can be orders of magnitude for some surfaces and highly charged incident ions, but seem to depend very sensitively on the properties of the impacted surface in addition to the fluence, energy and charge of the impacting ion. For oxides, potential sputtering yields are markedly enhanced and sputtered species, especially hydrogen and light ions, show marked dependence on both charge and dose