*<IP_ADDRESS> Precursor preparation*

The most popular hydrothermal synthesis process used for the preparation of BFO nanoparticles is the mineralizer-assisted route, in which mineralizers such as KOH (NaOH) [7, 19, 42, 43] or KNO3 [19, 44] are used for the preparation of precursors. This process allows the precursor to be conveniently prepared before hydrothermal synthesis by resolving the metal nitrates in purified water and KOH solution [45]. The aqueous precursor is produced by metal nitrates immersed in dilute nitric acid more generally than others. The method is then applied to the KOH solution for precipitation of Fe3+ and Bi3+. Precipitates are purified and cleaned to extract NO3− and K+ ions by pure water. The washed precipitates are then combined with KOH or NaOH solutions and additional KNO3 under continuous agitation [19, 44, 46]. In addition to these processes, the precursor scheme for the alteration of nanoparticles can often involve other additives, such as triethanolamine (TEA) [43] or sodium lauryl sulfate (SDS). In specific, the addition of TEA is observed to create a Fe-TEA complex that inhibits Fe hydroxide precipitation and may minimize synthesis to a maximum of 130oC [43]. Without the presence of the mineralizer, hydrothermal approaches may also be modified [45]. In hydrothermal synthesis of BiFeO3, the precursor of BiFeO3 is frequently synthesized by dissolving the metal sources, Bi and Fe nitrates (Bi(NO3)3.5H2O and Fe(NO3)3.9H2O, in deionized (DI) water or citric acid. The metal and citric acid molar ratio is equal to 1:1 ratio. Then, NH3 solution is added to neutralize the unreacted citric acid and change the pH to~9 [45]. Using this updated mineralizer-free method, the dried powder is eventually calcined at 350°C for 6 hr. to extract the final nanoparticles, which is an extremely phase-pure BFO with an average particle size of 55 nm.


**6. Discussion**

This section discusses the key challenges facingintegration of PVinto Kenya's electricity generationmix, and also puts some of the issues into a wider perspective.

A key technical challenge for integration of PV technology is the temporal match with the demand; solar power is available during the day and there must be a viable way of harnessing it for use when the sun is not up. In Kenya, electricity generation in the form of pumped hydroelectric power generation is seen as a viable option to replace run-of-river hydroelectric power plants whose production in susceptible to drought which result in reduced electricity generation capacity as well as outright power outages.

As it is, the electricity system in Kenya suffers from frequent power outages that are well documented. In a typical month, firms and homesteads connected to the grid experience on average 6.3 power outages, each lasting approximately five hours [19]. The economic cost of power interruptions is approximately 7.1% of the firms' sales; power outages therefore have a significant economic cost on businesses [19] and in turn on the Kenyan society.

There has been less emphasis on solar PV in Kenya. Specifically, no study has highlighted the potential of and possible barriers to solar PV generation where hydropower already exists. Studies on PV in Kenya have a leaning to integrate PV with other technologies. For policy-makers and international organizations keen to reduce carbon emissions and dependence on imported fuels, the deployment of hydro resources alongside solar PV is a viable option for many sub-Saharan African countries. It is here important to note the role played by hydropower sources, which supply approximately 30% of the end-use electricity demand in Kenya.

Kenya has a great potential for pumped-hydro storage for the integration of PV [2]. Dammed hydro or even pumped hydro storage are both dispatchable and thus offering regulating capability to the power system. For pumped hydro storage, low-cost surplus off-peak electric power can be used to fill reservoirs which is subsequently released through turbines during periods of high electrical demand. The cost of pumping water can easily be met from the revenue generated from selling power during peak demand periods—even when factoring in the cycle losses. At any rate, with cycle efficiencies in the 70% to 80% bracket [74] and modest cost per size [75], pumped hydro systems are a good storage candidate for large-scale PV integration.

In colder climates where heating systems offer flexibility through system-integration, options are more diverse with the use of cogeneration of heat and power [70,76–78], heat pumps [79,80], heat storage [75] and smart energy systems [81–84] for the integration of renewables. The potential for this sectorial integration between heat and electricity is not so pronounced in warmer climates. Also, in the future, electric vehicles provide an opportunity for integrating PV power [35,85–87], however this solution comes with a cost barrier.

There are conflicting standpoints and expectations of policy makers and utilities that constitute institutional and policy barriers. Incumbent electricity companies in Kenya are likely to favour maintaining the status quo since they have made investments in the existing electricity generation system. This creates path dependency and lock-in effect [87]. Kenya Power has the sole monopoly of managing

costs of connecting PV systems to the grid and they manage the grid single-handedly. At the same time, new forms of electricity generation such as PV generation try to break the lock-in and this clashes with the current Kenyan electricity regime that is mainly based on hydro, geothermal and fossil fuels. Resistance from the utility or other industry players can be sensed in the context of path dependence and lock-in, and therefore undermines integration of renewable sources of energy [36].

On the other hand, the supportive policies advanced by the Kenyan government towards renewable energy have contributed towards a growing interest among citizens related to solar energy. There is a range of different kinds of support instruments in use, such as a conducive environment for investment, innovative financing schemes, exemptions from value added tax and import taxes, standardized power purchase agreements and feed-in-tariffs which have led to the growth of PV market in Kenya [49].

These policies have raised the point that dynamic support structures for renewable energy technologies can aid in increasing their market penetration. A period of high subsidy may be particularly important to establish early growth in market share, but should be followed by adjustments in subsidies to prevent markets from growing too quickly. At the same time, [87] reminds that support must go beyond financial measures to be sustainable by offering training programs on operation and maintenance. Also, [87] found that one-off investment support or tax rebates were preferable to feed-in tariffs, as they were deemed more cost efficient and were likely to instil greater confidence in investors.

In addition, research institutions play a critical role in integration of PV systems through building of local capacity to handle installation, operation and maintenance of PV systems. As highlighted earlier, research and development has played a key in the advancement of PV technology in countries such as China. Kenya needs to invest more in research and development in order to scale up electricity generation from PV technology and therefore increase economic competitiveness of solar PV.

These linkages can be extended to collaborations between Kenya and the international community. In most African countries integration of solar PV systems (mainly small-scale) has been driven by donor-supported projects aimed at serving specific needs for electricity [1]. Historically, development of PV systems has been aided by the donor community which has facilitated acquisition of solar systems to local communities and institutions by providing the requisite resources. Arguably, availability of resources from PV actors from outside Kenya may also help scaling up of PV technology in the country. PV development in Kenya is also shaped by the market forces of demand and supply.

In terms of the proposed storage solution, PHS is already a well-established technology in several countries—and as our analyses show, it is also a technology that is applied or considered in conjunction with PV. The non-technical prospects of PHS in a Kenyan context have not been considered, but it is a technology that is traditionally owned and operated by larger players in electricity markets—power producers or transmission system operators e.g., Kenya Generating Company Limited and Kenya Transmission Company Limited could thus fit institutionally well into a system as the Kenyan with a strong central player in Kenyan Power and Lighting Company.


**4. Clinical presentation of iatrogenic bile duct injuries**

The most frequently observed clinical symptoms include jaundice, fever, chills, abdominal pain, pruritus. Clinical symptoms can be divided into two main groups. The first group are patients with the bile leakage in the early postoperative period due to the bile duct injury. In the presence of a drain in the peritoneal cavity, the injury indicates the appearance of bile in the drain. In patients without a catheter in the peritoneal cavity, bile leak into the abdominal cavity, leading to biloma or bile peritonitis. In these patients, jaundice is not observed because there is no cholestasis. In the second group of patients, usually in a remote time after surgery, there are primarily clinical symptoms resulting from cholestasis due to biliary obstruction. This is most commonly jaundice,


**Preface**

We are delighted to introduce this Reprint, showcasing a compilation of insightful scientific contributions spanning diverse fields. This collection centers on the significant realm of environments influenced by human activities, highlighting the essential role of remote sensing and geospatial approaches. Our goal with this compilation is to offer a comprehensive overview of state-of-the-art research and advancements in the covered subjects.

As Guest Editors, we are curating this Reprint with the aim of promoting knowledge sharing and fostering collaboration among experts and enthusiasts in these fields. We are confident that this collection will be a useful resource for our audience.

This compilation from the perspectives of new theories, datasets, methods, findings, and applications delves into essential questions: How can we monitor the environmental alteration by human activities at different spatiotemporal scales? How can we quantify, evaluate, and predict the impact of human activities on the environment? How can we decompose or evaluate the compound influence of various natural disturbances and human alteration on the environment? What is the corresponding pattern or mechanism of the environmental evolution to different human activities?

Through this Special Issue, we aim to foster knowledge exchange, encourage innovative research from diverse perspectives, and make scientific contributions to the environmental protection and governance affected by a variety of human activities.

We would like to express our sincere gratitude to all the authors who submitted their high-quality manuscripts to this Special Issue. We also thank all the reviewers who provided constructive comments and suggestions to improve the manuscripts. We appreciate the support and guidance from the editorial team of Remote Sensing.

We hope this compilation serves as a source of inspiration and prompts further exploration in the realms of "Remote Sensing and Geospatial Approaches for Studying the Environment Affected by Human Activities", making a significant impact on scientific advancement and environmental stewardship.

> **Jun Li, Xinyi Shen, Qiusheng Wu, and Chengye Zhang** *Editors*