scholarly journals Towards the Development of an Affordable and Practical Light Attenuation Turbidity Sensor for Remote Near Real-Time Aquatic Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1993
Author(s):  
Jarrod Trevathan ◽  
Wayne Read ◽  
Simon Schmidtke
Keyword(s):  
Water Quality ◽  
Real Time ◽  
Calibration Curve ◽  
Light Attenuation ◽  
Environmental Parameter ◽  
Design Rationale ◽  
Physical Constraints ◽  
Different Types ◽  
Monitoring Platform

Turbidity is a key environmental parameter that is used in the determination of water quality. The turbidity of a water body gives an indication of how much suspended sediment is present, which directly impacts the clarity of the water (i.e., whether it is cloudy or clear). Various commercial nephelometric and optical approaches and products exist for electronically measuring turbidity. However, most of these approaches are unsuitable or not viable for collecting data remotely. This paper investigates ways for incorporating a turbidity sensor into an existing remote aquatic environmental monitoring platform that delivers data in near real-time (i.e., 15-min intervals). First, we examine whether an off-the-shelf turbidity sensor can be modified to provide remote and accurate turbidity measurements. Next, we present an inexpensive design for a practical light attenuation turbidity sensor. We outline the sensor’s design rationale and how various technical and physical constraints were overcome. The turbidity sensor is calibrated against a commercial turbidimeter using a Formazin standard. Results indicate that the sensor readings are indicative of actual changes in turbidity, and a calibration curve for the sensor could be attained. The turbidity sensor was trialled in different types of water bodies over nine months to determine the system’s robustness and responsiveness to the environment.

Preparation and Adding Methods of Nessler's Reagent Having Effects on Determination of Water Quality Ammonia Nitrogen

2013 ◽  
Vol 726-731 ◽  
pp. 1362-1366 ◽  
Author(s):  
He Zhen Wu ◽  
Aie Cao
Keyword(s):  
Water Quality ◽  
Quality Control ◽  
Calibration Curve ◽  
Mass Concentration ◽  
Critical Factor ◽  
Ammonia Nitrogen ◽  
Control Effect ◽  
Recovery Test ◽  
Standard Solution

Nessler's reagent spectrophotometry method is used for determination of water quality ammonia nitrogen. The method is affected by many factors, of which Nessler's reagent is the most critical factor. Preparation and adding methods of Nessler's reagent influence the results of determination , which is based on the determination of absorbance and recovery test. Experimental results show that in the strict control of the speed and the amount of HgCl2 accession, we can get the best effect in the course of preparation of Nessler's reagent. Put a volume of standard solution into a 50mL colorimetric tube, add into Nessler's reagent when diluted with water to about 40mL and then add into water to the reticle (constant volume to 50mL). Determine the absorbance when colors are shown. Draw calibration curve with absorbance as ordinate and mass concentration of ammonia nitrogen as abscissa. The quality control effect of the determination of ammonia nitrogen can be improved by reducing uncertainties.

scholarly journals Sistema Nefelometrico Auto-referenciado Inmune a Fuentes de Luz Externas

2018 ◽  
Vol 3 (1) ◽  
pp. 111
Author(s):  
Salvador Vargas ◽  
Jossue Calvo
Keyword(s):  
Water Quality ◽  
Light Source ◽  
Calibration Curve ◽  
Sensor Calibration ◽  
Water Turbidity ◽  
Design And Implementation ◽  
Light Interference ◽  
Non Linear ◽  
External Sources

This paper describes the concepts and procedures for the design and implementation of a water turbidity sensor.  It is designed with the purpose of offering us water turbidity readings.  The sensor is designed according to the standard ISO 7027 "The water quality, determination of turbidity", which specifies four methods for the determination of the turbidity of the water.  The light source is an infrared led to 850 nm which is modulated in frequency to prevent external light interference, so that the sensor receiver is immune to external sources of light.  The calibration of this sensor gets a sensitivity of 0.0014 V/NTU and a non-linear error less than 10%, for a range between 0.1 NTU to 600 NTU.Keywords: Turbidity, Nephelometer, Turbidimeter, Sensor, Calibration Curve

COMPARISON OF VARIOUS METHODS FOR THE CHEMICAL ASSAY OF CORTICOIDS IN URINE

1955 ◽  
Vol 18 (4) ◽  
pp. 374-378
Author(s):  
Mogens Sprechler
Keyword(s):  
Calibration Curve ◽  
Periodic Acid ◽  
Reducing Power ◽  
Standard Technique ◽  
Phosphomolybdic Acid ◽  
Florisil Column ◽  
Chemical Assay ◽  
Chromatographic Procedure ◽  
Acid Reagent

SUMMARY Since 1949 about 10,000 urinary corticoid analyses have been performed routinely in our laboratory. The method used for this purpose was described in 1950 (Sprechler). We determine the corticoids which can be extracted from the urine with chloroform immediately after acidification to pH 1. The extract is washed with sodium hydroxide and water, a Girard separation is performed, and finally the reducing power of the ketonic fraction is measured by means of the phosphomolybdic acid reagent reaction. During the last few years two other chemical reactions have been used for comparison: The formaldehyde and the Porter-Silber method. After a thorough examination of the above methods a standard technique was followed. In the formaldehyde method a microdiffusion in a Conway unit was used instead of distillation of the formaldehyde following the oxidation with periodic acid. The calibration curve was corrected for loss of material by taking the standard doses of DOC through all the procedures of the method. A micromodification of the Porter-Silber method was chosen. Furthermore attempts were made to determine how specific the chromatographic procedure is in the determination of steroids in urinary extracts. For this purpose the Florisil column was used, and the technique described by Nelson & Samuels was followed. Finally we have investigated the glucuronide-bound corticoids in urine in a smaller series of objects.

EVALUASI KESESUAIAN PELAKSANAAN PROBITY AUDIT PADA BPKP PUSAT DENGAN PEDOMAN PROBITY AUDIT PENGADAAN BARANG/JASA PEMERINTAH

INFO ARTHA ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 17-34
Author(s):  
Fadlil Usman
Keyword(s):  
Public Sector ◽  
Real Time ◽  
Procurement Process ◽  
Assessment Activity

Probity audit is an independence assessment activity to ensure the goods/services procurement processes have been implemented consistently appropriate with the principle of upholding integrity, uprightness, honesty and fulfill certain occur legislation aimed for improving the accountability for the use of public sector fund. Probity audit is done in real time simultaneously with the goods/services procurement process. This study aims to evaluate the suitability of the implementation of probity audit conducted by BPKP Headquarter as agency that initiated the implementation of probity audit in Indonesia compared with the Probity audit Guidelines for Procurement of Goods/Services as criteria. The results of this study indicate that the implementation of probity audit conducted by BPKP Headquarter has been implemented adequately, but there are activities that do not fit the criteria, especially in the activities of the determination of the scope of the audit, the preparation of working papers and the follow-up monitoring of the audit results. Probity audit merupakan kegiatan penilaian (independen) untuk memastikan bahwa proses pengadaan barang/jasa telah dilaksanakan secara konsisten sesuai dengan prinsip penegakan integritas, kebenaran, kejujuran dan memenuhi ketentuan perundangan yang berlaku yang bertujuan meningkatkan akuntabilitas penggunaan dana sektor publik. Probity audit dilakukan secara real time yaitu bersamaan dengan pelaksanaan pengadaan barang/jasa. Penelitian ini bertujuan untuk melakukan evaluasi kesesuaian pelaksanaan probity audit yang dilakukan oleh BPKP Pusat selaku instansi yang menginisiasi pelaksanaan probity audit di Indonesia dibandingkan dengan kriteria berupa Pedoman Probity audit Pengadaan Barang/Jasa Pemerintah. Hasil dari penelitian ini menunjukkan bahwa pelaksanaan probity audit yang dilakukan oleh BPKP Pusat sudah dilaksanakan secara memadai, namun masih terdapat hal yang belum sesuai dengan kriteria terutama dalam kegiatan penentuan ruang lingkup audit, penyusunan kertas kerja dan pemantauan terhadap tindak lanjut hasil audit.

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