scholarly journals Comprehensive Evaluation of the GF-4 Satellite Image Quality from 2015 to 2020

2021 ◽  
Vol 10 (6) ◽  
pp. 406
Author(s):  
Wei Yi ◽  
Yuhao Wang ◽  
Yong Zeng ◽  
Yaqin Wang ◽  
Jianfei Xu

GaoFen-4(GF-4) is the highest spatial resolution Earth observation satellite operating in geosynchronous orbit. Its fixed Earth observation location, rapid responsiveness, and wide observation range make it popular in disaster and emergency monitoring. To evaluate the GF-4 image quality in detail on a long-term basis, this study analyzes the image quality after the commissioning phase by focusing on ground sample distance (GSD) and geometric and radiometric quality. The theoretical calculation, geometric and radiometric measurements, and on-site experiments results show that (1) the GSD of the GF-4 image is ~50 m at the nadir point and increases gradually with the distance away from the nadir point, (2) most external geometric errors are within the design requirements of 4 km despite some exceeding the limit, and the internal geometric errors are tested within 1 pixel, and (3) image sharpness is generally stable but varies with the atmosphere condition and imaging time, and the radiometric response gradually degrades at the rate of less than 5.5% per year.

Think India ◽  
2019 ◽  
Vol 22 (2) ◽  
pp. 296-304
Author(s):  
Biplab Tripathy ◽  
Tanmoy Mondal

India is a subcontinent, there huge no of people lived in river basin area. In India there more or less 80% of people directly or indirectly depend on River. Ganga, Brahamputra in North and North East and Mahanadi, Govabori, Krishna, Kaveri, Narmoda, Tapti, Mahi in South are the major river basin in India. There each year due to flood and high tide lots of people are suffered in river basin region in India. These problems destroy the socio economic peace and hope of the people in river basin. There peoples are continuously suffered by lots of difficulties in sort or in long term basis. Few basin regions are always in high alert at the time of monsoon seasons. Sometime due to over migration from basin area, it becomes empty and creates an ultimate loss of resources in India and causes a dis-balance situation in this area.


2020 ◽  
Vol 16 ◽  
Author(s):  
Kannappan Panchamoorthy Gopinath ◽  
Malolan Rajagopal ◽  
Abhishek Krishnan ◽  
Shweta Kolathur Sreerama

Background: Depletion and contamination of environmental resources such as water, air and soil caused by human activities is an increasingly important challenge faced around the world. The consequences of environmental pollution are felt acutely by all living beings, both on a short and long-term basis, thereby making methods of remediation of environmental pollution an urgent requirement. Objectives: The objective of this review is to dissect the complications caused by environmental degradation, highlight advancements in the field of nanotechnology and to scrutinize its applications in environmental remediation. Furthermore, the review aims to concisely explain the merits and drawbacks of nanotechnology compared to existing methods. Conclusion: The current and potential applications of nanomaterials and nanocomposites in the prevention, control and reduction of air, water and soil pollution and the mechanisms involved have been elucidated, as have their various merits and demerits. The applications of nanotechnology in the fields of carbon capture and agriculture have also received attention in this review.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1598
Author(s):  
Chih-Yu Chung ◽  
Yu-Ju Chen ◽  
Chia-Hui Kang ◽  
Hung-Yun Lin ◽  
Chih-Ching Huang ◽  
...  

Carbon quantum dots (CQDs) are emerging novel nanomaterials with a wide range of applications and high biocompatibility. However, there is a lack of in-depth research on whether CQDs can cause acute or long-term adverse reactions in aquatic organisms. In this study, two different types of CQDs prepared by ammonia citrate and spermidine, namely CQDAC and CQDSpd, were used to evaluate their biocompatibilities. In the fish embryo acute toxicity test (FET), the LD50 of CQDAC and CQDSpd was about 500 and 100 ppm. During the stage of eleutheroembryo, the LD50 decreased to 340 and 55 ppm, respectively. However, both CQDs were quickly eliminated from embryo and eleutheroembryo, indicating a lack of bioaccumulation. Long-term accumulation of CQDs was also performed in this study, and adult zebrafish showed no adverse effects in 12 weeks. In addition, there was no difference in the hatchability and deformity rates of offspring produced by adult zebrafish, regardless of whether they were fed CQDs or not. The results showed that both CQDAC and CQDSpd have low toxicity and bioaccumulation to zebrafish. Moreover, the toxicity assay developed in this study provides a comprehensive platform to assess the impacts of CQDs on aquatic organisms in the future.


1988 ◽  
Vol 13 (1) ◽  
pp. 10-14
Author(s):  
Brian Mitchell

The idea of prevention in child welfare is not new. The prevention of substitute placement of children whether on a temporary or long-term basis has been a fundamental principle of child welfare we have held to for many years in Victoria.However, it is only in the last decade that this principle is actually being carried out in practice by a number of voluntary agencies. For many children placement is still commonly used as a solution it is easier to place a child than to promote change within many multi-deficit families.


2010 ◽  
Vol 17 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Paula K Vuckovich

Failure to follow prescribed treatment has devastating consequences for those who are seriously and persistently mentally ill. Nurses, therefore, try to get clients to take psychotropic medication on a long-term basis. The goal is either compliance or adherence. Although current nursing literature has abandoned the term compliance because of its implications of coercion, in psychiatric nursing practice with patients suffering from serious long-term mental illness compliance and adherence are in fact different goals. The ideal goal is adherence, which requires the patient to be an active participant in the team. This goal is consistent with nurses’ ethical values, but for such patients this is frequently unrealistic. If the person is severely psychotic, treatment may be involuntary and the goal compliance. Psychiatric nurses participate in involuntary treatment and thus should acknowledge the ethical implications of compliance as a goal and not obscure the issue by calling compliance adherence.


2000 ◽  
Author(s):  
Shawn Chin Quee ◽  
Hai-Chao Han ◽  
David N. Ku

Abstract Standard tests are needed for evaluating and comparing the mechanical and biological functions of tissue engineered arteries and other vascular grafts. We propose an ex vivo organ culture system as a living system for testing tissue-engineered vascular grafts. This bench-top organ culture system mimics the physiological environment of arteries including the flow, pressure, and the axial stretch. Arterial mechanical properties and physiologic functions including compliance, burst pressure, and contractile functions can be assessed before an expensive long-term animal test is initiated. Test results of natural arteries indicate that organ culture is a valid model for comprehensive evaluation of tissue-engineered vascular grafts.


2018 ◽  
Vol 21 (4) ◽  
pp. 927-949 ◽  
Author(s):  
Okan Sirin ◽  
Md Ohiduzzaman ◽  
Emad Kassem ◽  
Dalim K. Paul

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