Steady-State and Dynamic Codes, Critical Review, Advantages and Disadvantages, Accuracy, and Reliability

Author(s):  
Vincenzo Corrado ◽  
Enrico Fabrizio
Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 522
Author(s):  
Zhen Li ◽  
Shunqi Mei ◽  
Yajie Dong ◽  
Fenghua She ◽  
Yongzhen Li ◽  
...  

Nanofibrous biomaterials have huge potential for drug delivery, due to their structural features and functions that are similar to the native extracellular matrix (ECM). A wide range of natural and polymeric materials can be employed to produce nanofibrous biomaterials. This review introduces the major natural and synthetic biomaterials for production of nanofibers that are biocompatible and biodegradable. Different technologies and their corresponding advantages and disadvantages for manufacturing nanofibrous biomaterials for drug delivery were also reported. The morphologies and structures of nanofibers can be tailor-designed and processed by carefully selecting suitable biomaterials and fabrication methods, while the functionality of nanofibrous biomaterials can be improved by modifying the surface. The loading and releasing of drug molecules, which play a significant role in the effectiveness of drug delivery, are also surveyed. This review provides insight into the fabrication of functional polymeric nanofibers for drug delivery.


Author(s):  
Zhe Wang ◽  
Qilun Zhu ◽  
Robert Prucka ◽  
Michael Prucka ◽  
Hussein Dourra

Spark-ignition engine in-cylinder air charge estimation is important for air-to-fuel ratio (AFR) control, maintaining high after-treatment efficiency, and determination of current engine torque. Current cylinder air charge estimation methodologies generally depend upon either a mass air flow (MAF) sensor or a manifold absolute pressure (MAP) sensor individually. Methods based on either sensor have their own advantages and disadvantages. Some production vehicles are equipped with both MAF and MAP sensors to offer air charge estimation and other benefits. This research proposes several observer-based cylinder air charge estimation methods that take advantage of both MAF and MAP sensors to potentially reduce calibration work while providing acceptable transient and steady-state accuracy with low computational load. This research also compares several common air estimation methods with the proposed observer-based algorithms using steady-state and transient dynamometer tests and a rapid-prototype engine controller. With appropriate tuning, the proposed observer-based methods are able to estimate cylinder air charge mass under different engine operating conditions based on the manifold model and available sensors. Methods are validated and compared based on a continuous tip-in tip-out operating condition.


Author(s):  
P. Moreno Zarate ◽  
Alexandre S. Shcherbakov ◽  
Svetlana Mansurova

Here we examine a new application of the adaptive detectors based on non-steady-state photo-electro-motive force effect for the detection of higher order  correlation functions, aiming the estimation of the parameters of ultra short optical pulses arranged in high-repetition trains. For this purpose three beam interferometer scheme with two signal beams modulated at different frequencies is proposed. Theoretical analysis of non-steady-state photo-EMF current generated by light distribution formed by superposition of three waves is performed and the possibility to detect simultaneously second and higher order correlation  function is demonstrated.  Potential advantages and disadvantages of such detection scheme for measuring the higher order auto-correlations functions are discussed.


1977 ◽  
Vol 14 (01) ◽  
pp. 19-41 ◽  
Author(s):  
Roderick A. Barr ◽  
Vladimir Ankudinov

This paper is designed to provide the ship designer with a description of the phenomenon of ship rolling, its prediction using available theoretical methods, and its reduction using available roll stabilization systems. A critical review of a number of available, predictive methods is provided. It is concluded that roll motions without stabilizers can be satisfactorily predicted using available methods and that it is necessary, in predicting rolling motions, to consider coupled roll-sway motions. The use of passive and active antiroll tanks and active fin stabilizers is discussed, and the size, performance, advantages, and disadvantages of each type are considered. Finally, the need for model tests to validate predicted roll stabilizer performance and the need for additional research in the area of roll motions are considered.


1999 ◽  
Vol 1 (3) ◽  
pp. 117-124 ◽  
Author(s):  
H. Colyer ◽  
T. Hlahla

The purpose of this paper is twofold; firstly, to present for wider consideration data collected about the role of information and support radiographers (ISRs) in the United Kingdom and secondly, to review critically issues of significance arising from the initial data collection and content analysis.The empirical material is taken from a much larger survey of Oncology Centres1 whose aim was to analyse the extent and effectiveness of information and support services for cancer patients in order to evaluate service provision in a less developed country. A short, self completed postal questionnaire to identified information and support radiographers was employed. It sought to identify the main components of the ISR role, underpinning qualifications, limitations and potential for development. 64% of ISRs surveyed responded (n = 22) and the findings are presented for consideration in this paper.The discussion comprises a critical review by the first author of some issues raised by the findings in the context of the national service framework for integrated provision2 and current developments in the practice and processes of therapeutic radiography. Specifically, the relative contribution of different aspects of the role of the ISR are evaluated, examining the benefits to patients and professionals alike. The difficulties of trailblazing a new role in a traditional, hierarchical service are explored. The necessity of a profession specific base for information and support provision in clinical oncology is questioned and it is suggested that, professionally, there are both advantages and disadvantages to this role development, but there is support for a less predatory, more interprofessional approach.


NANO ◽  
2021 ◽  
pp. 2130001
Author(s):  
Jialu Shen ◽  
Weifeng Chen ◽  
Zihan Yang ◽  
Guo Lv ◽  
Jie Cao ◽  
...  

Graphene quantum dots (GQDs) have aroused widespread attention because of their remarkable properties and potential applications. Herein, we discuss both the top-down and bottom-up strategies for the synthesis of GQDs. Different processes are presented to study their characteristics and the influence on the final properties of GQDs. The respective advantages and disadvantages of these methods are summarized. With regard to some important or novel ones, mechanisms are proposed for reference. In addition, the application of GQDs in biosensors is highlighted in detail. At last, we put forward some problems to be solved and give a brief prospect in their future developments. This review is very useful for quickly gaining knowledge and experience for synthesizing GQDs and designing the related novel biosensors.


1977 ◽  
Vol 67 (3) ◽  
pp. 343-382 ◽  
Author(s):  
M. W. Service

AbstractA critical review is presented of the many and varied procedures for sampling adult mosquitoes. All sampling methods are subject to bias, but human-bait collections are probably the most reliable single method for detecting and monitoring populations of anthropophilic species. The estimation of realistic man-biting rates, however, remains difficult. The recent advances in computer technology have generated considerable interest in population modelling, with the aim of getting a better insight into the complexities of population dynamics, mosquito control and disease transmission. Although such approaches may be informative, it is stressed that models should be based on meaningful values of the critical parameters and that these are best obtained from field populations. The difficulties of interpreting mosquito collections in both attractant traps, such as animal-baited traps, carbon-dioxide-baited traps and light-traps, and in non-attractant ones, such as Malaise traps, sticky traps, ramp traps, rotary traps, suction traps and vehicle-mounted traps, are described. Suction traps probably provide the least biased catches of aerial populations of mosquitoes, but, if populations as a whole are to be considered, then resting adults also must be adequately sampled, and this may prove difficult. It is emphasised that different trapping techniques usually sample different components of a population, and that the choice of sampling methods depends much on the type and quality of information required. The limitations of using mark-recapture techniques to study adult dispersal and obtain absolute population estimates are discussed, together with the advantages and disadvantages of applying simple and more complex mathematical procedures for analysing recapture data.


1996 ◽  
Vol 91 (6) ◽  
pp. 665-677 ◽  
Author(s):  
D. P. C. Leijssen ◽  
M. Elia

1. In order to establish biological and/or methodological explanations for the wide variability in recovery (50–100%) of labelled CO2 after administration of [13C]bicarbonate or [14C]bicarbonate, 34 human bicarbonate studies involving 480 subjects were analysed, and potential methodological issues were investigated in the laboratory. 2. Overall, continuous infusion studies reported a higher recovery than bolus studies (84 ± 11% versus 69 ± 12%; P < 0.001). No significant differences in recovery were found between 14C and 13C studies, children and adults, obese and lean subjects, or rest and exercise (steady state). Higher recoveries were found during feeding than during fasting (84 ± 8% versus 74 ± 7%; P < 0.001). Different methods used to analyse the results (0–10%) and different study protocols, which include differences in the duration of infusions and background drift in 13C enrichment (0–10%), contribute to the variability. 3. The laboratory studies suggest multiple sources of potential error, including loss of CO2 from the scintillation fluid (up to >30%, but only in 14C studies in which the scintillation fluid is not alkalized), diffusion of CO2 through syringes and tubing (0 to > 10%), non-linearity of CO2 analysers (up to 8%), inaccuracies in the measurement of bicarbonate concentrations (13C studies) or the strength of CO2-trapping agents (14C studies; 0–8%). 4. It is concluded that much of the variability in the recovery of labelled bicarbonate is likely to be attributable to methodological differences, and that attention to these will ensure better interpretation of metabolic studies that involve oxidation of carbon-labelled substrates.


Soil Research ◽  
2015 ◽  
Vol 53 (6) ◽  
pp. 577 ◽  
Author(s):  
Daniela Sauer

Soil chronosequence data may easily be interpreted in a too straightforward and simple a way if some relevant theoretical background is not kept in mind. This paper discusses pedological concepts that are considered relevant for soil chronosequence studies and may provide some guidance for establishing soil chronosequences and interpreting obtained data. Concepts related to the soil system, soil body, and soil-forming factors are introduced, and advantages and disadvantages of different types of soil chronosequences are pointed out. The question of whether soil formation reaches steady-state is raised, leading to the conclusion that some soil properties achieve steady-state whereas others do not, and that soil formation as a whole may only rarely reach a kind of near steady-state. The influence of climate and relief, and associated three-dimensional water and material fluxes in landscapes, are addressed, and concepts related to pedogenic processes, soil properties, and energy and matter transfers as drivers of soil formation are discussed. Feedback systems and thresholds in soil development are highlighted, the concept of progressive vs regressive pedogenesis is introduced, and potential shortcomings of soil chronosequence studies are addressed. Implications of each of the mentioned concepts for soil chronosequence studies are pointed out.


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