IC System Research Articles

Application of a portable ion chromatograph for real-time field analysis of nitrite and nitrate in soils and soil pore waters

Real-time monitoring of nitrite and nitrate is crucial for maintaining soil health and promoting plant growth. In this study, a portable ion-chromatograph (IC, Aquamonitrix) analyser, coupled with a field-applicable ultrasonic-assisted extraction method, was utilised for in-field determination of nitrate and nitrite in soils. This is the first application of this type of analyser to soil nutrients. On-site analysis of soil from a local sports field showed 94.8 ± 4.3 μg g−1 nitrate, with LODs of 32.0 μg g−1 for nitrate and 5.4 μg g−1 for nitrite. The results were in close agreement with those obtained using a conventional lab-based IC. Relative standard deviations (%RSDs) for soil analysis using Aquamonitrix were consistently below 10%. The obtained average recoveries of samples spiked with nitrite were 100% and 104% for the portable IC and conventional IC, respectively. Furthermore, to assess the suitability of portable IC for samples with high organic matter content, various natural organic fertilisers were extracted and analysed. The results showed 16.2 ± 0.7 μg g−1 nitrite and 28.5 ± 5.6 μg g−1 nitrate in sheep manure samples with LODs of 2.0 μg g−1 for nitrite and 12.0 μg g−1 for nitrate. The portable IC system was further demonstrated via real-time on-site analysis of soil pore-water acquired using a portable battery-based ceramic pore-water sampler. A continuous increase in nitrate concentration over time was observed (from 80 to 148 μg mL−1) in the soil pore-water in a vegetable garden four days after heavy rain. Unlike conventionally sampled natural waters, 7-day storage of the studied pore water samples revealed no changes in nitrate concentrations. An average of 558 ± 51 μg mL−1 nitrate was detected in the soil pore-water samples analysed on a spinach farm, immediately after irrigation.

Portable IC system enabled with dual LED-based absorbance detectors and 3D-printed post-column heated micro-reactor for the simultaneous determination of ammonium, nitrite and nitrate

BackgroundThe on-site and simultaneous determination of anionic nitrite (NO2−) and nitrate (NO3−), and cationic ammonium (NH4+), in industrial and natural waters, presents a significant analytical challenge. Toward this end, herein a 3D-printed micro-reactor with an integrated heater chip was designed and optimised for the post-column colorimetric detection of NH4+ using a modified Berthelot reaction. The system was integrated within a portable and field deployable ion chromatograph (Aquamonitrix) designed to separate and detect NO2− and NO3−, but here enabled with dual LED-based absorbance detectors, with the aim to provide the first system capable of simultaneous determination of both anions and NH4+ in industrial and natural waters. ResultsIncorporating a 0.750 mm I.D. 3D-printed serpentine-based microchannel for sample-reagent mixing and heating, the resultant micro-reactor had a total reactor channel length of 1.26 m, which provided for a reaction time of 1.42 min based upon a total flow rate of 0.27 mL min−1, within a 40 mm2 printed area. The colorimetric reaction was performed within the micro-reactor, which was then coupled to a dedicated 660 nm LED-based absorbance detector. By rapidly delivering a reactor temperature of 70 °C in just 40 s, the optimal conditions to improve reaction kinetics were achieved to provide for limits of detection of 0.1 mg L−1 for NH4+, based upon an injection volume of just 10 μL. Linearity for NH4+ was observed over the range 0–50 mg L−1, n = 3, R2 = 0.9987. The reactor was found to deliver excellent reproducibility when included as a post-column reactor within the Aquamonitrix analyser, with an overall relative standard deviation below 1.2 % for peak height and 0.3 % for peak residence time, based upon 6 repeat injections. SignificanceThe printed post-column reactor assembly was integrated into a commercial portable ion chromatograph developed for the separation and detection of NO2− and NO3−, thus providing a fully automated system for the remote and simultaneous analysis of NO2−, NO3−, and NH4+ in natural and industrial waters. The fully automated system was deployed externally within a greenhouse facility to demonstrate this capability.

Orange County IEEE Solid-State Circuits Society Hosts DL Prof. Nagata: Hardware Security and Safety of IC Chips and Systems [Chapters]

Orange County IEEE Solid-State Circuits Society Hosts DL Prof. Nagata: Hardware Security and Safety of IC Chips and Systems [Chapters]

DESIGN AND CONSTRUCTION OF A 1.7KVA PURE SINE WAVE INVERTER USING PULSE WIDTH MODULATION TECHNIQUE

This project is targeted on the design and construction of 1.7kVA pure sine wave following the high demand of constant and pure electricity sources for consumer homes or small commercial. The inverter ensures clean pure solar energy is converted from DC sources to AC voltages that can be used in consumer devices. The methodology that was adopted to achieve this project construction is the pulse-width modulation technique, which ensures that DC signals is fed to a MOSFET driver circuit which then produces AC signals. This current is then stepped up by a transformer to produce the desired 220 volts AC output voltage. The transformer we used also ensures that the inverter system can take up a load of 1.7kva. We found out that most inverters in the market produce a modified sine wave signal, therefore we used capacitor filters to ensure we obtain a clean pure sine wave as our output. We recommend that consideration should be made to the load being used for the inverter to ensure it doesn’t exceed its capacity. Also, an improved IC and MOSFET system can be used to obtain smother AC results. The aims and objectives of this project were all achieved at the conclusion of the project.

Дяӈ ката [Берегиня]: текст об обрядовой кукле лесных ненцев

This article presents a text in the Pur dialect of the Forest Nenets language. The text has to do with the traditional ritual doll of the For‑ est Nenets – Дяӈ ката, ‘Grandmother of the Earth’. The text’s author is a native speaker of Forest Nenets, and its publication was prepared in col‑ laboration with linguists. The text is accompanied by a Russian transla‑ tion and interlinear morpheme-by-morpheme glossing. The orthograph‑ ic system used for transcribing the text is introduced in the preface. Linguistic phenomena that have previously not been sufficiently de‑ scribed for the Forest Nenets language are commented on in footnotes.

Cadmium uptake and mycorrhization by cacao clones in agroforestry and monoculture systems of Peruvian Amazon

The production system influences the cadmium (Cd) content and mycorrhization in cocoa plantations. The objective of this study was to determine the effects of different production systems on Cd uptake and the presence of mycorrhizas in cacao clones in field conditions, in the Peruvian Amazon. Twelve subplots of 108 m2 were selected in representative cocoa cultivation systems under agroforestry (AF) and monoculture (MON), with the cocoa clones ICS and CCN. Significant differences and data distribution were evaluated using ANOVA, principal component analysis, and Tukey's tests. Mycorrhizal colonization was higher in the AF_ICS system (71.11%) while the length of the extraradical mycelium was higher in the AF_CCN system (17.23%). The highest Cd content in soils was found under the AF_CCN and AF_ICS systems, both with 0.39 mg kg-1. The Cd content in cacao roots, leaves, and beans were higher in the MON_CCN system with 1.87, 2.06, and 1.12 mg kg-1 respectively. Cocoa monocultures (with both clones) generally showed lower levels of mycorrhizal colonization than agroforestry systems, which in turn (also for both clones) presented higher Cd content in beans, even exceeding the limit established by the world health authorities.

THE EFFECT OF RECESSİONS IN THE WORLD ECONOMY ON STOCK EXCHANGES

Recession is defined as recession in the literal sense. It represents a significant economy-wide decline that lasts more than a few months. In other words, because the growth rate in the countrys economy is lower than the population growth rate, it is the per capita income. All macroeconomic indicators; Industrial production, employment, real income, wholesale and retail trade data are also included in this measurement. Recession periods are the periods in which there are decreases in the stock market in general and there are recessions in share prices. But investors who know the history of the stock market know that this can often be an opportunity. Companies that make good use of these periods will also gain greater profits after the recession. Recession periods may end after two quarters or may last longer. An economys exit from recession at the end of two quarters is called a V-type exit, and a longer-term exit is called a U-type exit. If the economy has contracted again after exiting a recession, then it is called a W-type recession or a double-dip recession. While the US economy recovered after the 2020 Covid period recession, it entered the recession period in 2022, where the Russia-Ukraine war was effective. However, the important point here is that with the end of the W-type recessions, the growth path in the economy is long-term and continues for at least 4-5 years. In this study, the effect of recessions on stock markets will be investigated. KEYWORDS: Economıc Recession, Stock Exchange, Econom Ic System.

Cartography and analysis of the urban growth, case study: Inter-communal grouping of Batna, Algeria

This paper focuses on the analysis of the urban macroform in terms of urban compactness and dispersion (urban sprawl) in the inter-communal grouping of Batna, which is composed of four adjacent interconnected commu- nal districts: Batna, Tazoult, Oued Chaaba and Fesdis. First, the urban macroform is examined by mapping the urban areas that are characterised by morphological changes over a period of 36 years utilising remote sensing and geograph- ic information system (GIS) through satellite images taken from Landsat TM and ETM +, Sentinel 2 (1984, 1996, 2008 and 2020). Next, the Shannon entropy method is utilised to determine compactness or dispersion of urban growth over time. In addition, a fractal analysis based on the box-counting method is used to assess the complexity and to explain the morphological reality of the macroform through urban changes. In order to predict the future change scenarios and spatial distributions of land use and land cover in the coming years the hybrid cellular automata (CA) – Markov method is used. The results of the remote sensing, Shannon entropy values and fractal indices demonstrate that Batna inter-municipal grouping has experienced moderate urban development according to the observed urban sprawl be- tween 1984 and 2020. These data are helpful in the urban planning and to provide decision-making tools.

Quality management in medical organization: evaluation categories for internal control effectiveness

Introduction. The creation and administration of internal control system for quality and safety of medical activities (internal control, IC) is an essential step of the management cycle in any medical organization. IC system is one of the most discussed types of control in the Russian healthcare today. At the same time, management of this local system in medical organization remains the subject of discussion.
 Objective. To analyze the impact of the completeness and intensity of activities carried out at medical organization (hereinafter referred to as MO) on the results of internal control.
 Materials and methods. Authors conducted a sociological study with a formalized questionnaire (checklist) to identify evaluation categories for the internal control effectiveness. The study participants were the internal control managers from 89 state MOs of the Chelyabinsk Region.
 Results. Increasing the stability of the internal control system as a mandatory and continuous activity for any MO requires the development of additional management measures, including creating a unified information framework, reducing the information gap between MOs within a region, expanding the use of incident and risk-based internal control technologies as well as analyzing the resources and staffing of IC subjects.
 For citation: Kuchin NЕ, Tyukov YuА. Quality management in a medical organization: evaluation categories for internal control effectiveness. City Healthсare. 2023;4(1): 50-60 doi: 10.47619/2713-2617.zm.2023.v.4i1;50-60.

Towards generic memory forensic framework for programmable logic controllers

A Programmable Logic Controller (PLC) is a microprocessor-based controller that is used to automate physical processes in critical infrastructure and various other industries and manufacturing sectors. Initially, PLCs were completely isolated from the Internet, and cyber security was not incorporated at the time of development. The introduction of industry 4.0 and the evolution of ICS systems to communicate over public IP addresses from the Internet enhanced productivity and efficiency, but Internet connectivity exposed the systems and their vulnerabilities, which led to an increase in cyber attacks. When a system is sabotaged/compromised, security analysts need to get to the root cause of the attack as quickly as possible to recover the system. To do so, memory forensic analysis is critical to provide a unique insight into the run-time memory activities and extract a reliable source of evidence. In this paper, we analyze the memory structure of the Schneider Electric Modicon M221 PLC. To build a memory profile, we reverse engineer the communication protocol and conduct differential analysis to gain knowledge about the structure of the memory and the low-level representation of control logic instructions. We then identify dynamic and static memory regions by modifying different project fields and conducting differential analysis, which allows us to identify boundaries of critical memory structures and extract important forensic artifacts that can be found in the memory. The Python implementation of the memory profile can help reduce the time and effort required for manual analysis in case of cyber incident or system failure.

Разработка доверенных средств проектирования ИС в базисе гетерогенных ПЛИС

This paper focuses on the development of trusted tools for designing digital circuits in the basis of heterogeneous field programmable gate arrays (FPGAs). Designing heterogeneous FPGAs is one of the most actively growing areas in Russian microelectronics at present. The paper discusses the main problems and challenges associated with the development of trusted computer-aided design tools. The authors propose a relevant approach to the development of a computer-aided design system based on the use of open-source software tools together with proprietary developments for its critical components. This approach allows to increase the efficiency and reliability of the design process in the basis of heterogeneous FPGAs. The paper considers such stages of the design flow in the basis of heterogeneous FPGAs as logic synthesis and technology mapping, different stages of layout synthesis and static timing analysis. The work is of interest to specialists in the field of microelectronics, as well as to researchers involved in the development of IC design tools and systems. The research results contribute to the improvement of existing IC design methods and tools, as well as to the development and expansion of the Russian electronic component base.

SYNTHESIS OF THREATS AND RISKS OF CYBER SECURITY OF MONTENEGRO - THE VULNERABILITY ASPECT OF INFORMATION COMMUNICATION INFRASTRUCTURE

That there are no untouchables and that cyber threats are entering Montenegro through the big doors, is indicated by the hacker attack on the Government of Montenegro. Fortunately, the hackers did not get hold of confidential data, but their act itself caused a serious act of endangering state security, especially because they breached the system that is networked with all state bodies. It was not the first time in 2022 that hackers broke into Government IC systems and state and private companies and organizations. Experts from the IT sector have been warning about the vulnerability of the system for a long time, but not loudly enough to be taken seriously. Let’s also mention the attack on Montenegro on the eve of joining NATO, where Montenegro was under increased cyber attacks, and the Ministry of Defense says that it is similar today.Cyber is no longer the world of gamers and geeks, it is increasingly becoming a prefix for terrorism, crime, and other types of threats (Kazerić 2017). Internet trade and the use of electronic services such as e-government are also on the rise. To the global trend, almost everything that was only tangible and materialized in the real world is moving to the virtual community. This brings with it many advantages, but also disadvantages, and one of them is certainly the vulnerability of critical information and communication infrastructure and the danger of cyber attacks. In such circumstances, the issue of security partially shifts the focus to cyber, that is, cyber security. Precisely for this reason, it is necessary to take a critical look at the existing information and communication infrastructure and analyze the existing threats and risks brought by the modern, cybernetic age. The synthesis of threats and risks is necessary so that we can adequately face them and predict the difficulties that may come our way, which could have significant consequences for national security.

Hydrodynamic characteristics of deep-water bridge floating foundations with different mooring systems

This paper focuses on the hydrodynamic characteristics of the floating foundations which are used to support the deep-water floating bridges. A model test is conducted for the bridge floating foundation considering three typical mooring systems, namely Incline Cables only (IC), Tension Legs only (TL), and Incline Cables & Tension Legs (IC&TL), for comparison. Based on statistical and spectral analyses, the hydrodynamic characteristics of floating foundations under wave and current, regarding platform motions and mooring tensions, are investigated. In IC system, the platform heave and roll motions are excited by waves with relatively wide range of frequencies, and a coupling effect between sway and roll is recognized. In TL system, remarkable resonance in sway motion is observed under irregular wave loading, while other responses are well suppressed. The responses of IC&TL system are generally dominated by platform sway resonance, and superior performance with respect to both static and dynamic behaviors is shown in this system. The floating foundation systems would behave statically under the current only condition, while for conditions combining wave and current, the superposed current would mitigate the horizontally dynamic responses, and enhance the vertically heave oscillations of the systems.

Peanut and cotton intercropping increases productivity and economic returns through regulating plant nutrient accumulation and soil microbial communities

BackgroundIntercropping (IC) has been widely adopted by farmers for enhancing crop productivity and economic returns; however, the underpinning mechanisms from the perspective of below-ground interspecific interactions are only partly understood especially when intercropping practices under saline soil conditions. By using permeable (100 μm) and impermeable (solid) root barriers in a multi-site field experiment, we aimed to study the impact of root-root interactions on nutrient accumulation, soil microbial communities, crop yield, and economic returns in a peanut/cotton IC system under non-saline, secondary-saline, and coastal saline soil conditions of China.ResultsThe results indicate that IC decreased the peanut pods yield by 14.00, 10.01, and 16.52% while increased the seed cotton yield by 61.99, 66.00, and 58.51%, respectively in three experimental positions, and consequently enhanced the economic returns by compared with monoculture of peanut (MP) and cotton (MC). The higher accumulations of nutrients such as nitrogen (N), phosphorus (P), and potassium (K) were also observed in IC not only in the soil but also in vegetative tissues and reproductive organs of peanut. Bacterial community structure analysis under normal growth conditions reveals that IC dramatically altered the soil bacterial abundance composition in both peanut and cotton strips of the top soil whereas the bacterial diversity was barely affected compared with MP and MC. At blossom-needling stage, the metabolic functional features of the bacterial communities such as fatty acid biosynthesis, lipoic acid metabolism, peptidoglycan biosynthesis, and biosynthesis of ansamycins were significantly enriched in MP compared with other treatments. Conversely, these metabolic functional features were dramatically depleted in MP while significantly enriched in IC at podding stage. Permeable root barrier treatments (NC-P and NC-C) counteracted the benefits of IC and the side effects were more pronounced in impermeable treatments (SC-P and SC-C).ConclusionPeanut/cotton intercropping increases crop yield as well as economic returns under non-saline, secondary-saline, and coastal saline soil conditions probably by modulating the soil bacterial abundance composition and accelerating plant nutrients accumulation.

IMPROVEMENT OF THE CYBER PROTECTION OFTHE ARMED FORCES TAKING INTO ACCOUNT THE EXPERIENCE OF COUNTERING MILITARY CYBER ATTACKS OF THERUSSIAN FEDERATION IN 2022

The article considers the possibilities of improving the cyber defense system of the Armed Forces of Ukraine and the Ministry of Defense of Ukraine in accordance with the goals and objectives defined in the decisions of the National Security and Defense Council of Ukraine and the Laws of Ukraine. A review of the requirements of normative documents on information and cyber security of Ukraine and similar documents of the United States of America was carried out. The considered algorithm for developing a risk management system in the direction of information security is outlined in the USA national standards. The scientific novelty of the work is that in the process of developing the risk management system in the information and communication systems (ICS) of the Armed Forces of Ukraine and the Ministry of Defense of Ukraine, it was proposed to create an decision support system that will be based on a specialized knowledge base capable of accumulating experience both during cyber-defense measures of the ICS and during the implementation of cyber-influences on the ICS of the enemy. An overview of open international standardization methods and relevant knowledge bases that can be used to update information on vulnerabilities and countermeasures in IC systems was carried out. The joint to use of open knowledge bases and specialized knowledge bases potentially can create new opportunities not only during cyber defense, but also during the implementation of cyber influences on the ICS of the enemy, therefore, this direction of research is promising and corresponds to the national interests of Ukraine

Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)

Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

Complementary resource use in intercropped faba bean and cabbage by increased root growth and nitrogen use in organic production

AbstractIntercropping can improve yield and nitrogen use efficiency in organic vegetable production by pairing crops with complementary resource use. An intercrop field experiment was conducted to determine yield, root growth and nitrogen (N) dynamics using faba bean (Vicia faba L.) grown as a vegetable and pointed cabbage (Brassica oleracea var. capitata cv. conica). Both crops were grown in monocropping (MC) and intercropping systems (IC). Minirhizotrons were used to measure root growth. Yield of pointed cabbage per metre row was 28% higher under the IC system than under MC, whereas faba bean yield as fresh seeds did not differ. The land equivalent ratio was 1.06, showing that improved yield under IC resulted from efficient land resource use. Even though MC cabbage had the highest aboveground biomass, total N accumulation was higher under IC and MC faba bean systems. Both root frequency and intensity were greater under IC faba bean rows compared with MC faba bean because of the presence of cabbage roots in faba bean rows. Monocropped cabbage had the highest root intensity and the lowest amount of soil mineral N in the 0–1.5 m depth after harvest. Monocropped cabbage was efficient in assimilating N, whereas MC faba bean was efficient in exporting N as harvestable yield. The nitrogen use efficiency using the IC system (75%) was higher than growing faba bean (44%) and cabbage (65%) alone. Thus, faba bean as an intercrop in organic cabbage production systems improves land and N use efficiency by complementary root growth.

Life Cycle Assessment of Sustainable Broiler Production Systems: Effects of Low-Protein Diet and Litter Incineration

We conducted a life cycle assessment (LCA) to compare environmental impacts of conventional (CNV) broiler chicken production in Japan with those of three mitigation options: a low-protein diet supplemented with more crystalline amino acids (LP), incineration of broiler litter (IC), and their combination (LP + IC). Feed production, feed transport, broiler housing, and manure management were included in the LCA, with 1 kg of liveweight of broiler chicken as the functional unit. The CNV environmental impacts were: climate change, 1.86 kg CO2e; acidification, 52.6 g SO2e; eutrophication, 18.3 g PO4e; energy consumption, 18.8 MJ. Since broiler manure management has a lower N2O emission factor, the LP diet’s effects on greenhouse gas (GHG) emissions were limited. Because a large amount of ammonia is emitted from broiler-litter composting and the LP diet reduced nitrogen excretion and consequent NH3 emission, the LP showed lower acidification and eutrophication potentials than CNV. The IC system reduced fuel consumption by utilizing the generated heat for broiler-house heating and thus had lower GHG emissions and energy consumption; it reduced ammonia emission from the manure-management process by incineration and thus had lower acidification and eutrophication potentials even when including NOX generation by litter incineration. The LP + IC system had lower environmental impacts than CNV: for climate change (by 16%), acidification (48%), eutrophication (24%), and energy consumption (15%). Mitigation opportunities for broiler chickens remain, and broiler production systems with mitigation options help produce chickens more sustainably.

SYSTEM DYNAMICS MODEL DEVELOPMENT BY ANALYZING CAUSES OF FUKUSHIMA DAIICHI NPP UNIT-1 ACCIDENT

— Fukushima Daiichi NPP accident occurred on March 11, 2011. A system dynamics model is developed by analyzing the chronological progression and causes of the Fukushima Daiichi NPP unit-1 accident applying causeeffect relationship and qualitative causal loop and feedback loop. The accident progression demonstrates that the safety system of the NPP could not function properly, resulting in the loss of core cooling and confinement of radioactive materials functions, and a severe accident with hydrogen explosion occurred. The system dynamics model shows that earthquake, tsunami induced flooding, design failure of Tsunami height, loss of all AC power, loss of DC power, loss of ultimate heat sink, failure of HPCI system, failure of IC system, design complexity of isolation valves of IC and lack of training on IC operation, delayed water injection to reactor, delayed operation of containment venting, lacking of compressed air, high reactor pressure, and harsh radiological condition are the causes of this severe accident. High reactor pressure and harsh radiological condition were produced during the accident, which positively boost accident progression by demonstrating the effect of system dynamics. The conservative design to protect power sources from natural events and the loss of all power for an extended period must be considered during future design of NPP.

SYSTEM DYNAMICS MODEL DEVELOPMENT BY ANALYZING CAUSES OF FUKUSHIMA DAIICHI NPP UNIT-1 ACCIDENT

Fukushima Daiichi NPP accident occurred on March 11, 2011. A system dynamics model is developed by analyzing the chronological progression and causes of the Fukushima Daiichi NPP unit-1 accident applying causeeffect relationship and qualitative causal loop and feedback loop. The accident progression demonstrates that the safety system of the NPP could not function properly, resulting in the loss of core cooling and confinement of radioactive materials functions, and a severe accident with hydrogen explosion occurred. The system dynamics model shows that earthquake, tsunami induced flooding, design failure of Tsunami height, loss of all AC power, loss of DC power, loss of ultimate heat sink, failure of HPCI system, failure of IC system, design complexity of isolation valves of IC and lack of training on IC operation, delayed water injection to reactor, delayed operation of containment venting, lacking of compressed air, high reactor pressure, and harsh radiological condition are the causes of this severe accident. High reactor pressure and harsh radiological condition were produced during the accident, which positively boost accident progression by demonstrating the effect of system dynamics. The conservative design to protect power sources from natural events and the loss of all power for an extended period must be considered during future design of NPP.