Sumber air bersih yang berasal dari sungai sudah tercemar dan tidak bisa digunakan untuk kebutuhan sehari-hari. Salah satu penyebab pencemaran air sungai adalah limbah kamar mandi. Sifat air limbah kamar mandi yang basa dan mengandung banyak deterjen mengakibatkan air tersebut susah diurai oleh mikroorganisme yang ada dalam air, agar air limbah tersebut dapat digunakan, maka perlu adanya proses daur ulang. Penelitian dilakukan menggunakan teknologi plasma untuk mengolah air limbah. Plasma dibangkitkan dengan menggunakan memodifikasi transformator flyback berfrekuensi 7 KHz, 8 KHz dan 10 KHz. Tegangan yang dihasilkan berupa tegangan tinggi (High Voltage) antara 5-24 KV. Variabel yang diteliti dari air limbah kamar mandi adalah pH dan TDS (Total Dissolve Solid). Proses daur ulang dimulai dengan dipaparkannya plasma pada permukaan air selama 20 menit dan dijaga pada suhu konstan. Hasil penelitian menunjukkan terjadi penurunan pH air dari 10,0 menjadi 8,1 dengan menggunakan teknologi plasma (electron discharge). Sedangkan untuk pengukuran TDS mengalami kenaikan dari nilai 135 ppm menjadi 210 ppm.

<span lang="EN-US">Developing a low-cost thermal cycler for a polymerase chain reaction (PCR) is becoming interested in the pandemic era caused by viruses. PCR is the standard gold for the diagnostic. However, in a low-income country, the availability of the device is limited. In this work, the development of a thermal cycler uses electronic modules available in the market. The central part is thermoelectric for heating and cooling, an embedded system to control, and a low-profile cooling fan. The system temperature control used a combination of feedforward, bang-bang, and proportional-integral-derivative (PID) control. The control parameter of the PID was successfully obtained by using Chien servo tuning. The feedforward and bang-bang control are used to optimize the cooling cycle and minimize the rise time. The system shows a well-suited temperature accuracy at the denaturation, annealing, and extension temperature with a temperature deviation of less than 0.5 °C. System performance is maintained even though the system has been running non-stop for 24 hours. The low-profile cooling fan, which is usually used for CPU cooling, shows good results in maintaining temperature stability.</span>

Desa Jabung merupakan suatu desa yang berada di Kecamatan Jabung, Kabupaten Malang. Kondisi air tanah di desa ini beragam, ada wilayah dengan potensi air tanah yang bagus seperti Dusun Krajan, namun beberapa dusun lain seperti Umpak, Boro Jabung, Mindi, dan Gunungjati mempunyai potensi air tanah yang kurang baik dan tergolong daerah yang mengalami kekeringan. Kegiatan pengabdian kepada masyarakat dari dosen Departemen Fisika Universitas Brawijaya dilakukan di Desa Jabung pada tanggal 11 September 2020 kepada perangkat desa Jabung. Sosialisasi dilakukan secara semi-daring (hybrid) dengan perangkat desa Jabung dan satu orang dosen pelaksana berada di Kantor Desa Jabung, serta dosen pelaksana yang lain mengikuti sosialisasi ini lewat zoom. Materi sosialisasi yang diberikan berupa pengetahuan mengenai Air Bawah Tanah (ABT) dan hasil pemetaan potensi ABT di Desa Jabung. Dari hasil evaluasi kegiatan sosialisasi ini, diketahui bahwa materi sosialisasi sangat diperlukan oleh perangkat Desa Jabung untuk mengatasi kekeringan di Desa Jabung, serta harapan untuk melakukan kegiatan yang serupa di masa yang akan datang.

Ultraviolet Light Emitting Diode (UV LED) is becoming popular, especially during the Covid-19 pandemic. UV LED has a specific wavelength with relatively narrow bandwidth, especially the one that has a shorter wavelength. On the other hand, UV LED has advantages in its low power consumption, compact size, and longer lifetime. This work shows that a wider bandwidth can be elicited by combining multiple UV LED sources. We have measured several low-cost UV LED, which is used as a germicidal lamp using a portable spectrometer that can detect a wavelength from 200 nm to 850 nm. The combined UV LED spectrum light ranges from 254 nm UVC to 400 nm UVA. The light spectrum produced by the LED shows a form of the Gaussian distribution model. Some LEDs have a peak wavelength at UVC around 270nm, and LEDs have a peak wavelength around 400nm at UVA. We can conclude that the low-cost UV LED can be used as a light source for portable or field spectrometers for specific wavelength.

Thermal Cycler is the main part of the Polymerase Chain Reaction (PCR), which becoming a gold standard for Covid-19 diagnosis. The virus multiplication in an order to a detectable concentration is done by placing the virus solution at a deterministic temperature cycle. The solution is placed in a small tube inserted in a temperature block. Temperature distribution of the thermal block is important to make all the tube with sample treated at the same at desired target temperature. Study on the thermal block made of aluminium 7075 was simulated using fluid dynamic finite element method. Heating and colling to the target temperature was done by providing heat source and heat absorber. The temperature distribution on the surface was mapped. The temperature gradient perpendicular to the heat source was calculated. Assuming the environment of the thermal block was still air, the heating and cooling speed at given heat source and heat removal were calculated using the model. The temperature gradient from the top surface to the bottom surface is less than 2.5°C. The temperature difference among point at the surface is less than 0.1°C.