I—The Control Characteristics of Hovercraft

1962 ◽  
Vol 15 (4) ◽  
pp. 359-364
Author(s):  
W. A. Pennington

Any discussion on the navigational problems of hovercraft must obviously be closely associated with the control characteristics of the craft. Although these machines have been widely publicized as capable of operating over almost any terrain which is reasonably flat, it will be assumed that the present discussion is concerned primarily with operation over water.The word hovercraft may be regarded as a generic term in the same category as aircraft, ship, motor vehicle &c., and practical examples are likely to take a variety of forms depending upon their particular application. Thus, the control characteristics and the way in which they affect the navigational problem are likely to vary, in degree at least, amongst the different types. Again, it must be realized that the hovercraft as a transport system is only at the beginning of a long development phase, and any remarks of a general nature which are made at this time must be read in that context. Even at this early stage, however, two distinct applications of the hovercraft principle, as applied to over-water transport machines, have emerged and it is important to appreciate the difference between them.

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Qizhi Zhang ◽  
Ying Wang ◽  
Yinting Zhou ◽  
Qiujuan Zhang ◽  
Chuan Xu

Abstract Background The abnormal expression of microRNA (miRNA) has been proved to be closely related to the occurrence and progression of tumors. A unique expression of multiple miRNAs has been found in different types of tumors. However, the correlation between miRNA and non-functional pituitary adenoma (NFPA) is not clear. In this study, miRNAs (miRNA-26b, miRNA-138, miRNA-206, and miRNA-let-7e) have been used as detection genes to compare the miRNA expression levels of NFPA subjects and healthy controls and to explore the expression of four different miRNAs in NFPA. Methods Ten untreated NFPA volunteers were served as subjects, and 10 normal subjects were selected as controls. Peripheral blood samples were collected, and four differentiated expressed miRNAs (miRNA-26b, miRNA-138, miRNA-206, and miRNA-let-7e) obtained in the early stage of the test group were detected, recorded, and archived by quantitative real-time PCR (qPCR). The difference and significance of endogenous miRNA expressions were explored through statistical analysis, hoping to find biomarkers for clinical treatment. Results The levels of miRNA-26b, miRNA-138, miRNA-206, and miRNA-let-7e in the peripheral serum of patients with NFPA were significantly lower than those in normal subjects (P < 0.05). Conclusion miRNA-26b, miRNA-138, miRNA-206, and miRNA-let-7e may be involved in the occurrence and progress of NFPAs. This study aims to study the biological targets of NFPA. It starts from the study of whether miRNA, miRNA-26b, miRNA-138, miRNA-206, and miRNA-let-7e may be tumor suppressor genes in NFPA, which provides a basis for further exploration of tumor markers of pituitary adenoma.


2016 ◽  
Vol 15 (2) ◽  
pp. 153-167
Author(s):  
Mohammad Ali Taslim ◽  
Md. Amzad Hossain

Purpose The difference in the export performance of different countries during the Great Recession 2008-2009 attracted some attention. It was frequently argued that the differences in export concentration were responsible for the differences in export performance: countries with more concentrated export portfolio suffered more during the recession compared to countries with more diversified export portfolio. Empirical evidence frequently failed to hold up this hypothesis, especially in the case of commodity concentration of export. Using disaggregated trade data and resorting to well-known theories of consumption demand, this paper argues that one of the main reasons for the difference in the export performance of different countries during the recession lay in the composition of the export basket and the general nature of the demand for different types of commodities. Design/methodology/approach Graphs and tables are first used to give a visual confirmation of the hypotheses advanced by the paper. Some theoretical arguments (proof) are advanced why consumer goods export should be less susceptible to recession. Finally cross-country data are used for regression analysis to test the export instability hypothesis. Findings All empirical evidence lend strong support to the hypothesis. Countries whose export basket comprised greater proportion of consumer goods suffered relatively less during the recession. Research limitations/implications The research could be enriched by using both time series and cross-section data and making a distinction between different types of consumer goods, namely, agricultural and manufactured goods. Data limitations did not permit this: United Nations Conference on Trade and Development (UNCTAD) data, used for this study, do not differentiate between these types of goods. Practical implications Export of more consumer goods may help reduce export revenue instability along business cycles. Originality/value To the best of the authors’ knowledge, there is no study that had ever attributed greater export stability to consumer goods export except those by the author(s).


2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P34-P35 ◽  
Author(s):  
Michael S Morris

Objective 1) Better recognize pathophysiology of postoperative tonsillectomy hemorrhage. 2) Be able to better differentiate the different types of post-tonsillectomy hemorrhage based upon understanding the vascular physiology and adjust management accordingly. Methods Post-tonsillectomy complications in children and adults were reviewed. 7 cases of hemorrhage, including 5 deaths, were carefully reviewed. Patients ranged between 2–40 years of age. This represents the largest series of post-tonsillectomy deaths reported to date. All postoperative deaths were due to bleeding and cardiopulmonary arrest. Post-mortem analysis was undertaken on those patients. CT angiography was reviewed in one surviving patient and the utility of this type of scanning is discussed. Results Post-tonsillectomy bleeding is one of the most worrisome otolaryngology concerns. Patients with bleeding on postoperative days 2–3 reported episodic bleeding stopping spontaneously. In these patients, the episode of unobserved bleeding signaled a vascular spasm with a likehood of recurrence. When the bleeding recurred it was massive and occured in a uncontrolled setting, leading to a poor outcome. Vascular trauma and spasm is likely. Conclusions Postoperative tonsillectomy bleeding is better managed by differentiating those patients with early stage bleeding on postoperative days 2–3. Direct examination of the operative field is imperative. Ancillary testing including CT angiograpy is helpful in the evaluation.


SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A136-A136
Author(s):  
S Brooks ◽  
R G J A Zuiker ◽  
G E Jacobs ◽  
I Kezic ◽  
A Savitz ◽  
...  

Abstract Introduction Seltorexant (JNJ-42847922), a potent and selective antagonist of the human orexin-2 receptor, is being developed for the treatment of major depressive disorder. Seltorexant also has sleep-promoting properties. Investigating the effects of sleep-promoting medications on driving is important because some of these agents (e.g. GABAA receptor agonists) may be associated with increased risk of motor vehicle accidents. We evaluated the effect of seltorexant on driving after forced awakening at night, using a validated driving simulator. Methods This double-blind, placebo and active-controlled, randomized, 3-way cross-over study was conducted in 18 male and 18 female healthy subjects. All subjects received seltorexant 40 mg, zolpidem 10 mg, or placebo 15 minutes before bedtime. Eighteen subjects were awakened at 2- and 6-hours post-dose, and the other 18 at 4- and 8-hours post-dose. At those timepoints, pharmacokinetics, objective (standard deviation of the lateral position [SDLP]) and subjective effects (using Perceived Driving Quality and Effort Scales) on driving ability, postural stability and subjective sleepiness were assessed. Results For seltorexant, the SDLP difference from placebo (95% confidence interval) at 2-, 4-, 6- and 8-hours post-dose was 3.9 cm (1.26, 6.60), 0.9 cm (-1.08, 2.92), 1.1 cm (-0.42, 2.63), and 0.6 cm (-2.75, 1.55), respectively vs. 9.6 cm (6.97, 12.38), 6.6 cm (3.53, 9.60), 4.7 cm (1.46, 7.85), and 1.3cm (-1.16, 3.80), respectively for zolpidem. The difference from placebo was significant at 2-hours after taking seltorexant, while the difference from placebo was significant at 2, 4 and 6-hours after zolpidem. Subjective driving quality was decreased for both drugs at all time points and driving effort was increased up to 4-hours post-dose for both medications. Subjective sleepiness showed a significant increase compared to placebo 2- and 4-hours after administration of either drug. Postural stability was decreased up to 2-hours after administration of seltorexant, and up to 4-hours after administration of zolpidem. Conclusion Compared to zolpidem, objective effects on driving performance were more transient after seltorexant administration and largely normalized by 4–6 hours post-dose. Support (if any) This work was sponsored by Janssen R&D.


Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Tim Tofan ◽  
Rimantas Stonkus ◽  
Raimondas Jasevičius

The aim of this research is to investigate related effect of dyeability to linen textiles related to different printing parameters. The study investigated the change in color characteristics when printing on linen fabrics with an inkjet MIMAKI Tx400-1800D printer with pigmented TP 250 inks. The dependence of color reproduction on linen fabrics on the number of print head passes, number of ink layers to be coated, linen fabric density, and different types of linen fabric was investigated. All this affects the quality of print and its mechanical properties. The change in color characteristics on different types of linen fabrics was determined experimentally. We determine at which print settings the most accurate color reproduction can be achieved on different linen fabrics. The difference between the highest and the lowest possible number of head passages was investigated. The possibilities of reproducing different linen fabric colors were determined.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Thomas J. Wilkinson ◽  
Daniel G. D. Nixon ◽  
Jared Palmer ◽  
Courtney J. Lightfoot ◽  
Alice C. Smith

Abstract Background Those living with kidney disease (KD) report extensive symptom burden. However, research into how symptoms change across stages is limited. The aims of this study were to 1) describe symptom burden across disease trajectory, and 2) to explore whether symptom burden is unique to KD when compared to a non-KD population. Methods Participants aged > 18 years with a known diagnosis of KD (including haemodialysis (HD) and peritoneal dialysis (PD)) and with a kidney transplant) completed the Leicester Kidney Symptom Questionnaire (KSQ). A non-KD group was recruited as a comparative group. Multinominal logistic regression modelling was used to test the difference in likelihood of those with KD reporting each symptom. Results In total, 2279 participants were included in the final analysis (age 56.0 (17.8) years, 48% male). The main findings can be summarised as: 1) the number of symptoms increases as KD severity progresses; 2) those with early stage KD have a comparable number of symptoms to those without KD; 3) apart from those receiving PD, the most frequently reported symptom across every other group, including the non-KD group, was ‘feeling tired’; and 4) being female independently increased the likelihood of reporting more symptoms. Conclusions Our findings have important implications for patients with KD. We have shown that high symptom burden is prevalent across the spectrum of disease, and present novel data on symptoms experienced in those without KD. Symptoms requiring the most immediate attention given their high prevalence may include pain and fatigue. Trial registration The study was registered prospectively as ISRCTN11596292.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3988
Author(s):  
Fátima Ternero ◽  
Pedro M. Amaral ◽  
Jorge Cruz Fernandes ◽  
Luís Guerra Rosa

A type of disc-on-plate test methodology was used to determine the wear behavior of metallic binders employed in the manufacturing of diamond impregnated tools. The disc consists of a special circular wheel that allows the binder materials alone (i.e., without diamond, but sintered under conditions identical to those of the complete tool) to be tested against a plate of stone material under pre-determined testing conditions. The testing conditions are intended to be equivalent to those used in the industrial processes. Using plates of five types of granite and one type of marble, this work comprises wear tests of 15 different types of metallic binders and two sintering modes conducted under, at least, three different values of contact-force. The analysis of the results demonstrated that the wear of the binders can be related to their mechanical properties through an empirical expression. The larger the difference between the characteristics of the tribological pair (binder versus stone), the higher is the correlation between the experimental wear data and the values given by the empirical expression. The relationships presented in this work allow predicting the wear behavior of the binder, and therefore may help in the design process of diamond tools. There was a clear difference between the wear behavior of metallic binders when they were employed against the two main classes of stone under analysis (marble and granite).


2021 ◽  
Author(s):  
Fang Zhou ◽  
Chang Su ◽  
Shuqi Xu ◽  
Linyuan Lü

Abstract In real-world networks, there usually exist a small set of nodes that play an important role in the structure and function of networks. Those vital nodes can influence most other nodes in the network via a spreading process. While most of the existing works focused on vital nodes that can maximize the spreading size in the final stage, which we call final influencers, recent work proposed the idea of fast influencers, which emphasizes nodes’ spreading capacity at the early stage. Despite the recent surge of efforts in identifying these two types of influencers in networks, there remained limited research on untangling the differences between fast influencers and final influencers. In this paper, we first distinguish the two types of influencers: fast-only influencers and final-only influencers. The former is defined as individuals who can achieve a high spreading effect at the early stage but lose their superiority in the final stage, and the latter are those individuals that fail to exhibit a prominent spreading performance at the early stage but influence a large fraction of nodes at the final stage. Further experiments based on eight empirical datasets, we reveal the key differences between the two types of influencers concerning their spreading capacity and the local structures. We also analyze how network degree assortativity influences the fraction of the proposed two types of influencers. The results demonstrate that with the increase of degree assortativity, the fraction of the fast-only influencers decreases, which indicates that more fast influencers tend to keep their superiority at the final stage. Our study provides insights into the differences and evolution of different types of influencers and has important implications for various empirical applications, such as advertisement marketing, and epidemic suppressing.


Nanomedicine ◽  
2021 ◽  
Author(s):  
Ahmed S AbdElhamid ◽  
Dina G Zayed ◽  
Lamia Heikal ◽  
Sherine N Khattab ◽  
Omar Y Mady ◽  
...  

Polymeric nanocapsules are vesicular drug delivery systems composed of an inner oily reservoir surrounded by polymeric membranes. Nanocapsules have various advantages over other nanovesicular systems such as providing controlled drug release properties. We discuss the recent advances in polymeric shell-oily core nanocapsules, illustrating the different types of polymers used and their implementation. Nanocapsules can be utilized for many purposes, especially encapsulation of highly lipophilic drugs. They have been shown to have variable applications, especially in cancer therapy, due to the ability of the polymeric shell to direct the loaded drugs to their target sites, as well as their high internalization efficacy. Those productive applications guaranteed their high potential as drug delivery systems. However, their clinical development is still in an early stage.


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