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"The qualities of the treated final effluents of a wastewater treatment plant located in a rural community of the Esaterm Cape Province of South Africa were assessed over the duration of 12 months...."

"The dynamic nature of meteorological data and the commercial availability of diverse photovoltaic systems, ranging from single-junction silicon-based PV panels to concentrated photovoltaic (CPV) systems utilizing multi-junction solar cells and a two-axis solar tracker, demand a simple but accurate methodology for energy planners and PV system designers to understand the economic feasibility of photovoltaic or renewable energy systems. In this paper, an electrical rating methodology is proposed that provides a common playing field for planners, consumers and PV manufacturers to evaluate the long-term performance of photovoltaic systems, as long-term electricity rating is deemed to be a quick and accurate method to evaluate economic viability and determine plant sizes and photovoltaic system power production. A long-term performance analysis based on monthly and electrical ratings (in kWh/m2/year) of two developed CPV prototypes, the Cassegrain mini dish and Fresnel lens CPVs with triple-junction solar cells operating under the meteorological conditions of Singapore, is presented in this paper. Performances are compared to other conventional photovoltaic systems."

"Buku yang berjudul "Handbook of electrochemical constants" ini ditulis oleh Roger Parsons. Buku ini membahas tentang aktivitas koefisien, dan teori elektrolit."

"Fitoplankton sebagai organisme fotosintetik berperan penting sebagai produsen primer. Fitoplankton menghasilkan oksigen serta bahan organik dalam perairan yang berfungsi sebagai pilar utama dalam jaring-jaring makanan. Kelimpahan fitoplankton dalam perairan diketahui dipengaruhi oleh berbagai faktor lingkungan fisika-kimia seperti intensitas cahaya, suhu, kecerahan, oksigen terlarut (dissolved oxygen), nitrat, fosfat, dan pH. Parameter fisika-kimia perairan diduga memiliki keterkaitan kuat dengan kelimpahan fitoplankton. Penelitian yang dilakukan bertujuan untuk mengetahui jenis serta kelimpahan fitoplankton dan mengetahui hubungan parameter fisika-kimia perairan terhadap kelimpahan fitoplankton di Situ Rawa Besar, Depok, Jawa Barat. Penelitian dilakukan pada bulan Februari—Maret 2023. Metode purposive sampling digunakan dalam pengambilan sampel dari 9 stasiun dengan 3x pengulangan. Sedgewick-rafter counting cell digunakan untuk pencacahan fitoplankton. Parameter fisika-kimia yang diukur di antaranya, intensitas cahaya, suhu, kecerahan, oksigen terlarut (dissolved oxygen), nitrat, fosfat, dan pH. Data parameter fisika-kimia dan kelimpahan fitoplankton dianalisis menggunakan metode PCA (Principal Component Analysis) dengan software R (R Studio). Rata-rata hasil parameter fisika-kimia menunjukkan konsentrasi DO sebesar 6,36 ppm, nitrat sebesar 6,77 mg/L, fosfat 0,02 mg/L, pH 9,54, kecerahan sebesar 13,30 cm, suhu sebesar 27,41°C, dan intensitas cahaya sebesar 8.201,3 lux. Hasil penelitian menunjukkan kelimpahan fitoplankton berada di rentang 27,8─518.945 individu/L. Planktothrix merupakan genus dengan kelimpahan tertinggi yaitu 518.945 individu/L dan kelimpahan terendah ada pada genus Actinastrum dengan nilai 27,8 individu/L. Analisis data dengan PCA menunjukkan korelasi positif antara kelimpahan fitoplankton dengan parameter fosfat, suhu, pH, dan intensitas cahaya.

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Phytoplankton as photosynthetic organisms play an important role as primary producers. Phytoplankton produce oxygen and organic matter in the waters which serve as the main pillars of food webs. The abundance of phytoplankton in waters is known to be influenced by various physico-chemical environmental factors such as light intensity, temperature, brightness, dissolved oxygen, nitrate, phosphate, and pH. The physico-chemical parameters of the waters are thought to have a strong relationship with the abundance of phytoplankton. The aim of the research was to determine the types and abundance of phytoplankton and to determine the relationship between the physico-chemical parameters of the waters and the abundance of phytoplankton in Lake Rawa Besar, Depok, West Java. The research was conducted in February-March 2023. The purposive sampling method was used in taking samples from 9 stations with 3 repetitions. Sedgewick-rafter counting cell is used for counting phytoplankton. The physico-chemical parameters measured included light intensity, temperature, brightness, dissolved oxygen, nitrate, phosphate, and pH. Physico-chemical parameter data and phytoplankton abundance were analyzed using the PCA (Principal Component Analysis) method with R software (R Studio). The average results of the physico-chemical parameters showed DO concentrations of 6.36 ppm, nitrates of 6.77 mg/L, phosphates of 0.02 mg/L, pH 9.54, brightness of 13.30 cm, temperature of 27.41°C, and a light intensity of 8,201.3 lux. The results showed that the abundance of phytoplankton was in the range of 27.8-518,945 individuals/L. Planktothrix is the genus with the highest abundance of 518,945 individuals/L and the lowest abundance is in the Actinastrum genus with a value of 27.8 individuals/L. Data analysis using PCA showed a positive correlation between the abundance of phytoplankton and the parameters of phosphate, temperature, pH, and light intensity."

"Sampah sisa makanan yang dihasilkan di kantin Fakultas Teknik UI memiliki persentase sebesar 73% dari total timbulan sampah. Jumlah sampah yang besar serta sifatnya yang mudah membusuk dan memicu kehadiran hewan pembawa penyakit seperti tikus, membuat pengolahan sampah sisa makanan perlu menjadi prioritas. Salah satu teknik pengolahannya adalah pengomposan, yaitu proses degradasi sampah organik oleh mikroorganisme menjadi material sejenis humus yang dapat dimanfaatkan.Tujuan penelitian ini adalah untuk menganalisis faktor-faktor (meliputi parameter fisik-kimia) yang mempengaruhi proses pengomposan, serta menganalisis hubungan dan pengaruh faktor tersebut terhadap aktivitas mikroorganisme selama proses pengomposan berlangsung. Analisis statistik dalam penelitian ini meliputi analisis faktor, korelasi, dan multivariabel.Berdasarkan analisis faktor yang dilakukan, terbentuk 2 faktor baru yang mempengaruhi proses pengomposan, yaitu faktor 1 dinamakan parameter yang menunjukkan hasil dari proses pengomposan, terdiri dari konduktivitas, salinitas, dan kadar air; dan faktor 2 dinamakan parameter yang mendukung proses pengomposan, terdiri dari rasio C/N, kadar karbon, pH, dan kadar nitrogen.Hasil analisis korelasi menunjukkan kadar air, rasio C/N, kadar karbon, pH, kadar nitrogen memiliki pengaruh terhadap aktivitas mikroorganisme. Berdasarkan analisis multivariabel, komposter 2 diperkirakan memiliki model regresi pengaruh faktor pengomposan terhadap aktivitas mikroorganisme yang terbaik. Sedangkan dilihat dari penurunan kadar karbonnya, komposter 1 memiliki konstanta laju pengomposan dan laju dekomposisi terbesar dibandingkan dua komposter lainnya, yaitu sebesar 0,0006 dan 0,0224%/hari.

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Food waste is likely to degrade quickly and smell, become a breeding ground for bacteria and attract rodents. Food waste from canteen at Faculty of Engineering has a percentage of 73% of the total waste generation. Enormous amount of food waste and its nature made food waste processing needs to be a priority. One of food waste treatment is composting, which is a process of organic waste degradation by microorganisms into humus-like material.This study aimed to analyze the factors (including physico-chemical parameters) that affect the composting process, and analyze the relationship and the influence of factors on microorganisms activities during the composting process. Statistical analysis in this study include factor analysis, correlation and multivariable analysis.Based on factor analysis, there are two new factors that affect composting, factor 1 consist of conductivity, salinity, and water content, then named parameter that indicates the result of the composting process, and factor 2 consist of C/N ratio, carbon content, pH, and nitrogen content, then named parameters that support the composting process.Results of correlation analysis showed that moisture, C/N ratio, carbon content, pH, and nitrogen content has correlation to microorganisms activities. Based on multivariable analysis, composter 2 were estimated to have the best regression models. While based on carbon reduction, composter 1 has the largest composting rate constant and decomposition rate than the two largest composter at 0,0006 and 0,0224 %/day"

"Pengomposan merupakan salah satu opsi teknologi yang efisien dan ramah lingkungan dalam penanganan limbah lumpur IPAL. Penelitian ini bertujuan untuk menganalisis kualitas fisik-kimia kompos, aktivitas mikroorganisme dan enzim, serta pengaruh parameter fisik-kimia terhadap aktivitas mikroorganisme dan enzim selama proses pengomposan lumpur dengan bulking agent sampah daun. Pengomposan menggunakan sistem open windrow selama 48 hari dengan campuran lumpur dan bulking agent 1:1 dan 2:3 untuk Kompos 1 dan 2.Hasil penelitian menunjukkan bahwa temperatur kompos berada pada rentang 28o-37,5oC, namun pengomposan mampu mengurangi total koliform hingga mencapai 99,92% dan 99,96% pada Kompos 1 dan 2. Kualitas akhir pH, C/N, dan fecal koliform pada kompos secara umum telah memenuhi kriteria kompos matang (SNI No 19/2004). Aktivitas bakteri proteolitik dan selulolitik terus meningkat dan mencapai puncaknya pada hari ke-34 dengan jumlah mencapai 1010 dan 1012 CFU/gram. Parameter pH, rasio C/N, kadar air, dan kadar volatil memiliki pengaruh yang lebih signifikan terhadap aktivitas mikroorganisme dan enzim kompos (p<0,1).

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Composting is one of technology options that can be considered as an alternative treatment to sewage sludge. The aimed of this study was to analyze the changes in physico-chemical parameters, microbial and enzyme activities, and effect of physico-chemical parameters on microbial and enzyme activities during the composting of sewage sludge and leaves as the bulking agents. The composting process was carried out for 48 days and use open windrow system. The mixture of sewage sludge and bulking agents for Compost 1 and 2 were 1 : 1 and 2 : 3, respectively.The results showed that values for temperature ranged from 28o-37,5oC, yet it could reduce total coliform up to 99.92% and 99.96% for Compost 1 and 2. The quality compost on pH, C/N ratio, and fecal coliform generally have met the criteria as mature compost (SNI No. 19/2004). Proteolytic and cellulolytic bacterial activities tended to increase and reached peak value up to 1010 and 1012 CFU/gram on the 34th day. Parameters of pH, C/N ratio, moisture content, and volatile solid have a more significant effect on the microbial and enzyme activities (p<0,1)"

"ABSTRAKPenelitian ini menganalisis pengaruh iradiasi sinar gamma terhadap sifat-sifat fisiko-kimia dan biologi membran kitosan, kolagen, dan paduan kitosan/kolagen. Membran kitosan, kolagen, dan kitosan/kolagen dibuat dengan penguapan pelarut dan membran diiradiasi sinar gamma (0, 15 atau 25 kGy). Pengujian untuk mengamati gugus fungsi, kuat tarik, perpanjangan putus, daya serap air, permeabilitas, sterilitas serta daya tembus mikroba. Data diuji statistik. Terdapat perubahan gugus fungsi, penurunan kuat tarik, perpanjangan putus, daya serap air dan permeabilitas membran serta kenaikan sterilitas pada membran tanpa dan dengan iradiasi, kecuali untuk daya tembus mikroba. Iradiasi sinar gamma pada semua membran menimbulkan perubahan sifat fisiko-kimia dan sterilitas

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ABSTRACTThe objectives of this study is to analyze the effects of gamma-ray irradiation to physico-chemical and biological properties chitosan, collagen and blend of chitosan/collagen membranes. The solvent evaporation technique is used to prepare chitosan, collagen and chitosan/collagen membranes, and sterilized by gamma-ray irradiation (with dose of 0, 15 or 25 kGy). Functional groups, mechanical strength, water retention, permeability, sterility and microbial penetration are observed. The data was analyze statistically. Functional groups, tensile strength, elongation at breaks, water retention, permeability, and sterility are changes, except for microbial penetration. Gamma-ray irradiation on chitosan, collagen and blend of chitosan/collagen membranes shows changes of physico-chemical and sterility."