Pemodelan Matematis Pengurangan COD Dalam Air Limbah Industri Penyamakan Kulit Secara Adsorpsi Kontinyu Menggunakan Abu Terbang Bagas

The objective of this research was to obtain suitable mathematical model for ChemicalOxygen Demand (COD) removal originated from tannery wastewater using bagasse fly ash incontinuous system. In the column experiment, effect of flowrate, concentration of wastewater,and bulk density were studied. Three models: Adams-Bohart, Thomas, and Yan were applied toexperimental data to predict the breakthrough curve. The best model was evaluated usingcorrelation coefficients. Yan model was found to give the most accurate to describe dynamicbehavior of the column experiment. The best result was obtained at flowrate of 100 mL/min,concentration of 400 mg/L, and bulk density of 61 g/L. The Yan kinetic constant (k ) and the Yadsorption capacity (q ) were 0.3210 mL/mg/min and 17.0947 mg/g respectively and the Ycorrelation coefficient obtained was 0.9379

Electromagnetic wave absorption and structural properties of wide-band absorber made of graphene-printed glass-fibre composite

Lightweight composites combining electromagnetic wave absorption and excellent mechanical properties are required in spacecraft and aircraft. A one- dimensional metamaterial absorber consisting of a stack of glass fibre/epoxy layers and graphene nanoplatelets/epoxy films was proposed and fabricated through a facile air-spraying based printing technology and a liquid resin infusion method. The production process allows an optimum dispersion of graphene nanoplatelets, promoting adhesion and mechanical integration of the glass fibre/epoxy layers with the graphene nanoplatelets/epoxy films. According to experimental results, the proposed wide-band absorber provides a reflection coefficient lower than −10 dB in the range 8.5–16.7 GHz and an improvement of flexural modulus of more than 15%, with a total thickness of ∼1 mm. Outstanding electromagnetic wave absorption and mechanical performance make the proposed absorber more competitive in aeronautical and aerospace applications

Pengaruh Ukuran Dan Fraksi Organik Terhadap Kuantitas Dan Kualitas Timbulan Lindi

Timbunan sampah pada landfill (TPA) akan mengalami degradasi dan akan menghasilkan cairan (lindi) baik kuantitas maupun kualitasnya. Kuantitas dan kualitas timbulan lindi dari sampah perkotaan akan dipengaruhi oleh beberapa faktor seperti: komposisi dan karakteristik sampah, kadar air, umur sampah dan kondisi cuaca (iklim). Pada kegiatan studi ini bertujuan untuk mengetahui pengaruh komposisi sampah (jumlah fraksi organik) dan karakteristik sampah (ukuran butiran) terhadap karakteristik timbulan lindi.Dalam rangka untuk mendapatkan tujuan studi, maka metode yang diterapkan adalah melakukan percobaan laboratorium menggunakan reaktor biodegradasi volume 1500 mL. Dalam percobaan ini digunakan dua kelompok reaktor yaitu; kelompok pertama, digunakan untuk pengujian pengaruh persentase fraksi organik, sedangkan kelompok kedua dimaksudkan untuk pengujian pengaruh ukuran butiran sampah terhadap karakteristik lindi.Sebagai parameter kualitas lindi ditentukan TSS, BOD, dan COD, sedangkan parameter kuantitas lindi adalah volume cairan yang keluar dari reaktor. Berdasarkan hasil percobaan diketahui bahwa jumlah (persentase) fraksi organik dan ukuran butiran sampah dapat berpengaruh terhadap karakteristik timbulan lindi. Secara keseluruhan konsentrasi TSS, BOD, dan COD semakin besar sejalan dengan bertambahnya persentase fraksi organik. Hal yang sama terjadi untuk ukuran butiran samaph semakin kecil, maka TSS, BOD, dan COD semakin besar. Adapun volume timbulan lind

Infrared Screening of Residential Buildings for Energy Audit Purposes: Results of a Field Test

Abstract: In the European Union (EU), the building sector is responsible for approximately 40% of total energy consumption. The existing building stock is inefficient and can, and indeed must be retrofitted to address this issue. The practical implementation of the European strategies requires knowledge of the energy performance of existing buildings through energy audit techniques. Application of thermography in the fields of energy are very widespread, since, through such a non-invasive investigation, and through correct interpretation of infrared images, it is possible to highlight inefficiencies in buildings and related facilities. The paper shows and discusses the results of an infrared audit campaign on 14 existing buildings located in Milan Province (Italy) made in different construction periods and characterised, therefore, by different building technologies. The U-values obtained in an indirect way through the thermography of the opaque walls of the buildings investigated, were compared with the actual known values in order to verify the reliability of the method and the possible margin of error. The study indicated that the category of buildings in which the application of this method is sufficiently reliable is that of solid-mass structure buildings, the most widespread in Italy, whereas in the case of buildings whose external walls are insulated, the percentage of deviation is very high

Studi Metode Penambahan Perak Nitrat Pada Saringan Keramik Terhadap Escherichia Coli Pada Air Minum

Problematika air tercemar mikrobiologis di Yogyakarta berdasar hasil pemantauan rutin oleh Dinas Kesehatan Kota Yogyakarta pada tahun 2011 menunjukkan bahwa pada parameter mikrobiologis terdapat 596 (67%) sumber air bersih (sumur) penduduk belum memenuhi syarat sesuai Permenkes 492/MENKES/PER/IV/2010, demikian juga pada tahun 2010 dan 2009 masing masing 68,8% dan 63,2% dari sampel yang diperiksa, sedangkan untuk pemeriksaan terhadap air perpipaan (PDAM) pada tahun 2011 masih terdapat 8,9 % dari sampel yang tidak memenuhi syarat. Hal tersebut terjadi pada pemukiman padat penduduk yang disebabkan keterbatasan lahan sehingga jarak antara peresapan jamban dengan sumur penduduk kurang dari persyaratan. Penggunaan Filter Keramik sebagai pengolahan air pada tingkat rumah tangga telah banyak dipelajari dan diteliti Riset filter keramik dikembangkan untuk persiapan keadaan darurat bencana dan pemukiman padat penduduk. Penelitian ini dilakukan pada tahun 2013-2014 dengan menggunakan rancangan analitik observasional, dengan pendekatan pre test-postest group design dengan analisis kuantitatif eksperimen dilaksanakan didalam laboratorium. Hasil menunjukkan tidak terdapat perbedaan pada metode penambahan perak nitrat ke dalam saringan keramik, sehingga pengembangan saringan keramik lebih mudah dan sangat memungkinkan menjadi alternatif untuk penyediaan air bersih dan layak konsumsi terutama pada keadaan darurat kebencanaanProblems of microbiologically contaminated water in Yogyakarta based on the results of routine monitoring by the City Health Office Yogyakarta in 2011 showed that the microbiological parameters are 596 (67%) of clean water sources (wells) population is not eligible in accordance Permenkes 492 / Menkes / Per / IV / 2010 , as well as in 2010 and 2009, respectively 68.8% and 63.2% of the samples examined, while for the examination of water piped (PDAM) in 2011, there are 8.9% of the sample were not eligible. It occurs in a densely populated residential area due to limited so that the distance between the infiltration wells latrine with a population less than the requirement. Use of Ceramic Filter as water treatment at household level has been widely studied and researched Research ceramic filters developed for the preparation of emergency response and densely populated area. This study used observational analytic design, the pretest-posttest approach to group design with quantitative analysis experiments were carried out in the laboratory. The results showed no difference in the method of adding silver nitrate into the ceramic filters, so that the development of ceramic filters easier and it is possible to be an alternative to the provision of clean and potable water, especially in an emergency disaster

Search for Neutron Flux Generation in a Plasma Discharge Electrolytic Cell

Following some recent unexpected hints of neutron production in setups like high-voltage atmospheric discharges and plasma discharges in electrolytic cells, we present a measurement of the neutron flux in a configuration similar to the latter. We use two different types of neutron detectors, poly-allyl-diglicol-carbonate (PADC, aka CR-39) tracers and Indium disks. At 95% C.L. we provide an upper limit of 1.5 neutrons cm^-2 s^-1 for the thermal neutron flux at ~5 cm from the center of the cell. Allowing for a higher energy neutron component the largest allowed flux is 64 neutrons cm^-2 s^-1. This upper limit is two orders of magnitude smaller than what previously claimed in an electrolytic cell plasma discharge experiment. Furthermore the behavior of the CR-39 is discussed to point our possible sources of spurious signals.Comment: 4 pages, 3 figure