Effects of three iron material treatments on hydrogen sulfide release from anoxic sediments

In eutrophic coastal regions, hydrogen sulfide (H2S) is a harmful material released from sediments under anoxic conditions. To suppress its release, we conducted laboratory experiments and assessed the impacts of treatment with three iron materials (Fe, Fe2O3, and FeOOH), focusing on the area-specific H2S release rate. These materials qualitatively exhibited a substantial suppression of H2S release; however, smaller treatment levels (<150 mmol m−2) were ineffective. FeOOH exhibited the best performance, followed by Fe2O3, and Fe. These differences were likely caused by variations in the oxidation or reduction potential of the materials and their reaction rates with H2S. A simplified model suggested that the required minimum Fe2+ concentration was determined using the H2S diffusivity, reaction rate constant, and treatment penetration depth. As the former two are physical constants, the latter must control the H2S release rate. Iron materials were experimentally confirmed to persist for over three weeks, and the effective treatment level was theoretically estimated as being capable of suppressing H2S release for more than a year. Our results will contribute to coastal environmental management and particularly benefit port authorities who manage enclosed and eutrophicated harbors and navigation channels where slag application should be avoided.

Perancangan Spiral Kondensor untuk Pengolahan Sampah Plastik Menjadi Bahan Bakar Minyak dengan Proses Pirolisis

This study aims to determine the dimensions of the spiral groove condenser to convert plastic waste into fuel and determine the material's effectiveness for making spiral groove condensers. This research was conducted in stages: potential identification, data collection, equipment design and calculation, design validation, testing, and equipment feasibility test. In the testing and equipment feasibility test, namely by inserting plastic waste into the pyrolysis process reactor, then heated to a temperature of 180 oC and an evaporation process occurs, the vapors obtained are then condensed to be fuel. The spiral groove condenser design is made with a length of 3 m, a diameter of 30 cm, and a height of 34 cm use ½ inch galvanized iron material and a plate thickness of 0.0127 mm. The cooling water circulation process uses a spiral iron pipe, with a temperature of steam entering the condenser 180 oC and the temperature of the water in the condenser is 40 oC. From 1000 gr of plastic waste can be produced as much as 100 ml of fuel.ABSTRAKPenelitian ini bertujuan untuk mengetahui dimensi kondensor alur spiral untuk merubah sampah plastik menjadi bahan bakar minyak, untuk mengetahui efektifitas bahan pembuatan kondensor alur spiral. Penelitian ini dilakukan dengan tahapan : identifikasi potensi, pengumpulan data, desain peralatan dan perhitungan, validasi desain, pengujian dan uji kelayakan alat. Pada proses pengujian dan uji kelayakan alat yaitu dengan memasukkan sampah plastik kedalam reaktor proses pirolisis, selanjutnya dipanaskan sampai temperatur 180 oC dan terjadi proses penguapan, uap yang yang diperoleh selanjutnya di kondensasi menjadi bahan bakar minyak. Rancangan kondensor alur spiral yang telah dibuat dengan panjang 3 m, berdiameter 30 cm dan tinggi 34 cm menggunakan bahan besi galfanis ½ inch dan tebal plat 0.0127 mm, proses sirkulasi air pendingin menggunakan pipa besi spiral, dengan suhu uap yang masuk ke dalam kondensor 180 oC dan temperatur air pada kondensor 40 oC. dari 1000 gr sampah plastik dapat dihasilkan sebanyak 100 ml bahan bakar minyak.

PERANCANGAN MESIN PENGAYAK DAUN KERING BAHAN BAKU PUPUK ORGANIK DI CV. GLOBAL BUMI PUTRA DENGAN PENDEKATAN METODE PAHL AND BEITZ

In the current condition of more advanced technology, all activities will be easy with the emergence of various new tools that have more usability than the basic capabilities of the previous tools. The more sophisticated the tool, the lighter the work done during the production process. CV. Global Bumi Putra, one of the organic fertilizer factories in the city of Jember, is still carrying out the sieving process in a traditional way. To increase the yield of dry leaf organic fertilizer, a dry leaf sieving machine was made. The method used to design this machine is the Pahl and Beitz method. There are 4 design stages in this method, namely planning and explaining tasks, designing product concepts, designing product forms, and the final phase of detailed design. From the results of the design using the Pahl and Beitz method, the design of the dry leaf sieving machine with the machine frame uses iron material, in the form of a cube for the outside. AC motor drive with electrical energy sources, transmission using belts and pulleys. Minimum machine design with size P = 2 m, W = 1.5 m, T = 2 m. The sieve on the machine is tubular, the size of the sieve net is 4 cm. The average yield of 2 sacks of chopped leaves using a manual sieve was 5.36 kg in 10.31 minutes. Meanwhile, from the test results of the sieving machine that was made, the average sieve yield of 2 chopped leaf sacks was 5.92 kg in 03.49 minutes.

ANALISIS FAKTOR KERUGIAN WASTE MATERIAL BESI BETON GEDUNG BERTINGKAT

Material as one of the components that has a contribution of 40-60% of the project cost in the research of Intan et al., 2005. Concrete is currently being studied because it is one of the five materials that affects 80% of material costs.. The purpose of this research is to examine how much the loss of iron concrete material waste and the ranking of the factors that influence it in multi-storey building projects. The research method is by conducting a questionnaire to contractors. The data collection process is carried out by distributing questionnaires in multi-storey building projects in Jakarta. Measuring the value of the questionnaire as many as 64 respondents used the Likert measurement technique. The sequence of data processing, first done by testing the validity and reliability testing. After that, these factors are ranked using the Relative Importance Index method. The result is a loss of Concrete Iron material waste of 7.5% and ratings that affect the loss of concrete are: not planning reinforcement bestat, complicated image detailing, cutting errors due to lack of understanding of work drawings / carelessness, lack of / unclear image information, use of wrong so that it needs to be replaced, the remaining cuts due to the process of use and a design change. Keywords: multi-storey building; reinforcing steel; waste material AbstrakMaterial sebagai salah satu komponen yang mempunyai kontribusi sebesar 40-60% dari biaya proyek di dalam penelitian Intan et al, 2005. Besi beton saat ini mau diteliti karena merupakan salah satu dari lima material mempengaruhi 80% biaya material. Tujuan penelitian ini meneliti berapa besar kerugian waste material besi beton dan peringkat faktor faktor yang mempengaruhinya pada proyek bangunan gedung bertingkat . Metode penelitian dengan melakukan kuesioner terhadap kontraktor. Proses pengumpulan data yang dilakukan adalah dengan menyebar kuesioner di proyek bangunan gedung bertingkat yang berada di Jakarta. Pengukuran nilai kuesioner sebanyak 64 responden digunakan teknik pengukuran Likert. Urutan pengolahan data, pertama dilakukan dengan uji validitas dan uji reliabilitas. Setelah itu faktor-faktor tersebut ditentukan peringkat dengan metode Relative Importance Index. Hasilnya adalah kerugian waste material Besi Beton sebesar 7,5 % dan peringkat yang mempengaruhi kerugian besi beton adalah:tidak merencanakan bestat penulangan, pendetailan gambar yang rumit, kesalahan pemotongan karena kurang memahami gambar kerja/kecerobohan,informasi gambar kurang/tidak jelas, penggunaan material yang salah sehingga perlu diganti, sisa pemotongan karena proses pemakaian dan adanya perubahan desain.

Synchrotron-Based Nano-XANES Reveals Intracellular Heterogeneity of Iron Species in Magnetotactic Bacteria

<p>This report demonstrates how scanning X-ray fluorescence microscopy (SXFM) and nanoscale X-ray absorption near-edge structure (nano-XANES) can spatially and chemically identify intracellular iron species at the single-cell level, creating an opportunity to examine the role of iron storage in magnetite biomineralization. Fe K-edge nano-XANES measurements of <i>Magnetospirillum gryphiswaldense</i> in varied iron media conditions and iron storage capacity revealed intracellular iron heterogeneities through a distinction between formed magnetosomes and intracellular iron material. This work highlights the potential of nano-XANES in providing an experimental advantage in the multidisciplinary field of biomineralization.</p>