Orientation dependent thermal conductance in single-layer MoS 2

We investigate the thermal conductivity in the armchair and zigzag MoS2 nanoribbons, by combining the non-equilibrium Green's function approach and the first-principles method. A strong orientation dependence is observed in the thermal conductivity. Particularly, the thermal conductivity for the armchair MoS2 nanoribbon is about 673.6 Wm−1 K−1 in the armchair nanoribbon, and 841.1 Wm−1 K−1 in the zigzag nanoribbon at room temperature. By calculating the Caroli transmission, we disclose the underlying mechanism for this strong orientation dependence to be the fewer phonon transport channels in the armchair MoS2 nanoribbon in the frequency range of [150, 200] cm−1. Through the scaling of the phonon dispersion, we further illustrate that the thermal conductivity calculated for the MoS2 nanoribbon is esentially in consistent with the superior thermal conductivity found for graphene

Nitrogen Transformation in Flooded Soil : Application of Rice Straw and Rice Straw Composts and Its Effect on Nitrogen Uptake and Acetylene Reduction Activity in Rice Plant Rhizosphere

The use of organic materials aimed in reducing the dependence on inputs such as chemical fertilizers can contribute to sustainability and improving the low N fertilizer efficiency of rice plants in paddy soils. Therefore, better understanding of N transformation in flooded soils, particularly the microbial transformation of N-organic amendments to plant-available N, is needed for most efficient use of soil and organic materials N for aiding in the selection of N management practices for sustainable agriculture. The experiments were conducted at the laboratory and in the greenhouse of Soil Department, Faculty of Agriculture, Bogor Agricultural University. Incubation experiment was conducted at room temperature for 120 days to observe the availability of N-NH4+ in soil amended rice straw or rice straw composts and its combination with urea. After 21 days of incubation period, the rice straw amended soils showed that NNH4+ release was higher than the other treatments. The 4-monthand 8-month-compost of rice straw showed that N mineralization rate was lower and the N availability was lower than rice straw. The results of pot experiment in greenhouse revealed that the added rice straw was comparable with urea in its effect on the increase of dry matter weight of rice plants, number of tillers, Nuptake of rice, and recovery N efficiency. The application of rice straw, however, promoted the activity of nitrogenase enzyme higher than rice straw composts. The effect of rice straw on observed parameters were much better than its composts

OPTIMALISASI WAKTU FERMENTASI PEMBUATAN ZAT WARNA ALAM INDIGO (INDIGOFERA TINCTORIA)

Tanaman Indigo jenis indigofera tinctoria tumbuh tersebar luas di Indonesia juga dinegara lain diantaranya Taiwan, Jepang, India, dan Thailand. Tanaman ini sudah ada sejak jaman nenek moyang dan para perajin sejak telah menggunakan pewarna indigo alami untuk memberi warna biru (wedel) pada pembuatan batik dan tenunan tradisional kuno. Kendala yang dihadapi saat ini adalah saat proses fermentasi daun indogo yang menghasilkan hasil yang berbeda (warna biru) bahkan kadang tidak diperoleh hasil. Dengan demikian perlu dilakukan penelitian proses dan mekanisme pembuatan zat warna indigo melalui proses fermentasi. Bahan yang digunakan adalah daun dari tanaman indigo jenis indogofera tinctoria yang berasal dari Gunung Kidul (sepanjang pantai Krakal), Bantul (Imogiri dan sepanjang pantai Trisk), dan Kulonprogo Provinsi Darah Istimewa Yogyakarta. Adapun variasi waktu fermentasi yang digunakan adalah 6, 12, 18, 24, 36, 36, 42, 48, 54, 60, 66jam, pada suhu kamar dengan pelarut air. Selain fermentasi proses yang dilewati pada kondisi kritis saat pembuatan zat warna indigo adalah, pengeburan (aerasi) atau pengikatan pewarna oleh alka, proses pereduksi dengan bahan pereduksi gula atau tetes, dan proses oksidasi. Dari hasil evaluasi pengujian diperoleh:jenis tanaman Indigofera tinctoria dari daerah Gunung Kidul diperoleh hasil pasta warna lebih bagus dari jenis tanaman Indigofera Tinctoria dari daerah Kulon Progo dan Karang Tengah (Imogiri). Optimalisasi waktu fermentasi yang disarankan berdasarkan penelitian supaya hasil pewarnaan optimal adalah 36-48 jam, menghasilkan rendeman sebesar 15,63 % dengan kadar (indigo+kapur) 35,97% berdasarkan 62,43% kadar air. Sedang untuk ketahanan luntur warna terhadap Pencucian yaitu antara 4 s/d 4 — 5, sedangkan ketahanan luntur warna terhadap gosokan 3 — 4 dan terhadap sinar matahari sebesar 4-5. Kata kunci: daun tanaman indigo, fermentasi, pengeburan, pewarnaa

Upadłość państwa z perspektywy prawa międzynarodowego

"Zjawisko upadłości państwa wymaga pogłębionej analizy nie tylko politologicznej, ale i prawnomiędzynarodowej. Trzeba bowiem odpowiedzieć na wiele ważnych pytań: 1) jakie konsekwencje prawnomiędzynarodowe niesie za sobą omawiane zjawisko?; 2) czy współczesne prawo międzynarodowe jest w stanie sprostać temu zjawisku?; 3) jakie jest miejsce państwa we współczesnym prawie międzynarodowym?; 4) czy prawnomiędzynarodowe pojęcie państwa nie uległo zmianie na przełomie XX i XXI w.?; 5) w jaki sposób omawiane zjawisko może wpłynąć na rozwój prawa międzynarodowego w XXI w.? "(...

A practical assessment of risk-averse approaches in production lot-sizing problems

This paper presents an empirical assessment of four state-of-the-art risk-averse approaches to deal with the capacitated lot-sizing problem under stochastic demand. We analyse two mean-risk models based on the semideviation and on the conditional value-at-risk risk measures, and alternate first and second-order stochastic dominance approaches. The extensive computational experiments based on different instances characteristics and on a case-study suggest that CVaR exhibits a good trade-off between risk and performance, followed by the semideviation and first-order stochastic dominance approach. For all approaches, enforcing risk-aversion helps to reduce the cost-standard deviation substantially, which is usually accomplished via increasing production rates. Overall, we can say that very risk-averse decision-makers would be willing to pay an increased price to have a much less risky solution given by CVaR. In less risk-averse settings, though, semideviation and first-order stochastic dominance can be appealingalternatives to provide significantly more stable production planning costs with a marginal increase of the expected costs.Peer reviewe

Jahresbericht 2016

Ein Rückblick auf das akademische Jahr 2015/16 Berichtszeitraum 1.9.2015 - 31.8.201

PERBAIKAN WAKTU SET-UP DENGAN MENGGUNAKAN METODE SMED (STUDI KASUS PT NAGA BHUANA ANEKA PIRANTI)

PT Naga Bhuana Aneka Piranti is a furniture company that produces garden furnitures, indoor furnitures, and also many kinds of handycrafts. This is done to meet the market demands nowadays. PT Naga Bhuana Aneka Piranti is using mass production as the production system. Now, PT Naga Bhuana Aneka Piranti is producing folding chairs. To meet the demand, PT Naga Bhuana Aneka Piranti needs a finishing time that is suitable for the definite time. The problem that is faced by PT Naga Bhuana Aneka Piranti is the lateness time for finishing the folding chairs so that it does not meet the scheduled plan. The lateness in many departments makes finishing time unsuitable with the definite schedule. Because of the problem, PT Naga Bhuana Aneka Piranti should reduce the set-up time to solve the problem of lateness in finishing the folding chairs. Reducing set-up time can be done by using Single-Minute Exchange of Die (SMED) method. The SMED method separates set-up time activities to become two activities, which are internal set-up and external set-up. Internal set-up is an activity that is only done when the machines are not operated. External set-up is an activity that can only be done when the machine is being operated. By changing internal set-up to become external set-up, then the set-up activities that is done when the machine is stopped can be done when the machine is operated so the time for the set-up can be minimized. The result of data analysis shows that by the application of SMED method, the set-up time of the production of folding chairs for each station can be reduced up to 11.23 minutes/ day. The set-up time for each station before SMED application was 67.73 minutes/ day, and after SMED application, it can be reduced to 56.5 minutes/ day. The time saving for the set-up can add the company income up to Rp. 6.360.000,00/ month. Key words : SMED method, set-up time, external set-up, internal set-up