19 research outputs found
Origami-inspired soft twisting actuator
Soft actuators have shown great advantages in compliance and morphology
matched for manipulation of delicate objects and inspection in a confined
space. There is an unmet need for a soft actuator that can provide torsional
motion to e.g. enlarge working space and increase degrees of freedom. Towards
this goal, we present origami-inspired soft pneumatic actuators (OSPAs) made
from silicone. The prototype can output a rotation of more than one revolution
(up to 435{\deg}), more significant than its counterparts. Its rotation ratio
(=rotation angle/ aspect ratio) is more than 136{\deg}, about twice the largest
one in other literature. We describe the design and fabrication method, build
the analytical model and simulation model, and analyze and optimize the
parameters. Finally, we demonstrate the potentially extensive utility of the
OSPAs through their integration into a gripper capable of simultaneously
grasping and lifting fragile or flat objects, a versatile robot arm capable of
picking and placing items at the right angle with the twisting actuators, and a
soft snake robot capable of changing attitude and directions by torsion of the
twisting actuators.Comment: 9 figures. Soft Robotics (2022
Cigarette Smoking in Male Patients with Chronic Schizophrenia in a Chinese Population: Prevalence and Relationship to Clinical Phenotypes
The high prevalence of smoking in schizophrenia of European background may be related to smoking's reducing clinical symptoms and medication side effects. Because smoking prevalence and its associations with clinical phenotypes are less well characterized in Chinese than European patients with schizophrenia, we assessed these smoking behaviors using clinician-administered questionnaires and the Fagerstrom Test for Nicotine Dependence (FTND) in 776 Chinese male schizophrenia and 560 control subjects. Patients also were rated on the Positive and Negative Symptom Scale (PANSS), the Simpson and Angus Extrapyramidal Symptom Rating Scale (SAES), and the Abnormal Involuntary Movement Scale (AIMS). We found that the schizophrenia patients had a higher lifetime incidence of smoking (79% vs 63%), were more likely to be heavy smokers (61% vs 31%), and had lower smoking cessation rates (4% vs 9%) (all p<0.0001) than controls. Among the schizophrenia patients smoking prevalence increased with age, with the largest difference from controls in the age cohort of 55–75 years: 75% vs 46% (p<0.0001). Among the schizophrenia smokers 73% started to smoke before the onset of their illness by an average of 7.6 years. The patients with schizophrenia who were current smokers scored significantly lower on the PANSS negative symptom subscore (p<0.005), and on the SAES symptom scale (p<0.04; Bonferroni corrected p>0.05) than the non-smoking patients. These results suggest that Chinese males with schizophrenia smoke more frequently than the general population. Further, smokers with schizophrenia may display fewer negative symptoms and possibly less parkinsonism than non-smokers with schizophrenia
Effect of Different Initial CaO/SiO<sub>2</sub> Molar Ratios and Curing Times on the Preparation and Formation Mechanism of Calcium Silicate Hydrate
To better understand the pozzolanic activity in fly ash used as a supplementary cementitious material in cement or concrete, calcium silicate hydrate (C-S-H) has been synthesized by adding silica fume to a supersaturated calcium hydroxide solution prepared by mixing calcium oxide and ultrapure water. Thermogravimetric analysis results have revealed the variation in the weight loss due to C-S-H in the samples and the conversion ratio of calcium oxide (the μCaO value), which represents the proportion of calcium oxide in the initial reaction mixture used to produce C-S-H, with curing time. The weight loss due to C-S-H and the μCaO value were both maximized (13.5% and 90.4%, respectively) when the initial C/S molar ratio was 1.0 and the curing time was 90 d. X-ray diffraction (XRD) analysis has indicated that C-S-H in the samples after curing for 7 d had the composition Ca1.5SiO3.5·xH2O. 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis has revealed that the degree of polymerization of C-S-H increased with an increase in curing time for samples with an initial C/S molar ratio of 1.0. The ratio of internal to terminal tetrahedra (Q2/Q1) increased from 2.29 to 4.28 with the increase in curing time from 7 d to 90 d. At curing times ≥ 28 d, a leaf-like C-S-H structure was observed by scanning electron microscopy (SEM). An ectopic nucleation–polymerization reaction process is proposed for the formation mechanism of C-S-H
Public Concern about Haze and Ozone in the Era of Their Coordinated Control in China
In China, due to the implementation of the Action Plan for Prevention and Control of Air Pollution (APPCAP), the concentrations of PM2.5 (fine particulate matter) and severe haze in most cities have decreased significantly. However, at present, haze pollution in China has not been completely mitigated, and the problem of O3 (ozone) has become prominent. Therefore, the prevention and control of haze and O3 pollution have become important and noticeable issues in the field of atmospheric management. We used the Baidu search indices of “haze” and “ozone” to reflect public concerns about air quality and uncover different correlations between level of concern and level of pollution, and then we identified regions in China that require public attention. The results showed that (1) over the last decade, the search index of haze had a rapid trend of variation in line with changes in haze pollution, but that of O3 had a relatively slowly increasing trend; (2) the lag days between the peaks of public concern and the peaks of air pollution became increasingly shorter according to daily data analysis; and (3) 96 polluted cities did not receive sufficient public attention. Although periods of heavily haze-polluted weather, which affects visibility, have generated much public concern, periods of slight pollution have not received enough public attention. Public health protection and environmental participation regarding these periods of slight pollution in China deserve appropriate levels of attention
Solid waste-based dry-mix mortar using fly ash, carbide slag, and flue gas desulfurization gypsum
The hydration characteristics, performance, and economic feasibility of inorganic cementitious materials prepared using circulating fluidized bed fly ash (FA), carbide slag (CS), and flue-gas-desulfurization gypsum (FGDG) are investigated, focusing particularly on FA-CS binary and FA-CS-FGDG ternary cementitious systems. Experimental results show that the compressive strength of the binary system is less than that of the ternary one. The ternary cementitious material exhibits strong synergistic effects, as the 28 days compressive strength of the ternary system can reach 6.35Â MPa, suggesting that it has good prospects for practical application. A dry-mixed mortar using the material has been manufactured and tested in a pilot project; it meets Chinese government quality standards and reduces cost and carbon emissions relative to traditional mortar. The 28 days compressive strength of dry mix mortar can reach 13.1Â MPa, the production cost of solid waste-based dry-mixed mortar was reduced by approximately 48.8%, and the carbon dioxide emission reduction ratio was 82.9%
Sb2O3 nanobelt networks for excellent visible-light-range photodetectors
Excellent photoconductive properties have been found in Sb(2)O(3) nanobelts synthesized by a surfactant-assisted solvothermal method. Visible-light photodetectors have been designed from Sb(2)O(3) nanobelt networks using micrometer-wide gold wires as masks. Photodetectors show high sensitivity to visible light, high stability, and reproducibility. Fast response and decay times (<0.3 s) are comparable or even better than these parameters in many other metal oxide nanoscale photodetectors. The dominant mechanism of excellent photoconductivity is attributed to the barrier height modulations in the nanobelt-to-nanobelt contact regions. These results demonstrate that Sb(2)O(3) nanobelt networks can indeed serve as high-performance photodetectors in the visible light range
Vapor–Liquid Sol–Gel Approach to Fabricating Highly Durable and Robust Superhydrophobic Polydimethylsiloxane@Silica Surface on Polyester Textile for Oil–Water Separation
Large-scale fabrication
of superhydrophobic surfaces with excellent durability by simple techniques
has been of considerable interest for its urgent practical application
in oil–water separation in recent years. Herein, we proposed
a facile vapor–liquid sol–gel approach to fabricating
highly durable and robust superhydrophobic polydimethylsiloxane@silica
surfaces on the cross-structure polyester textiles. Scanning electron
microscopy and Fourier transform infrared spectroscopy demonstrated
that the silica generated from the hydrolysis–condensation
of tetraethyl orthosilicate (TEOS) gradually aggregated at microscale
driven by the extreme nonpolar dihydroxyl-terminated polydimethylsiloxane
(PDMSÂ(OH)). This led to construction of hierarchical roughness and
micronano structures of the superhydrophobic textile surface. The
as-fabricated superhydrophobic textile possessed outstanding durability
in deionized water, various solvents, strong acid/base solutions,
and boiling/ice water. Remarkably, the polyester textile still retained
great water repellency and even after ultrasonic treatment for 18
h, 96 laundering cycles, and 600 abrasion cycles, exhibiting excellent
mechanical robustness. Importantly, the superhydrophobic polyester
textile was further applied for oil–water separation as absorption
materials and/or filter pipes, presenting high separation efficiency
and great reusability. Our method to construct superhydrophobic textiles
is simple but highly efficient; no special equipment, chemicals, or
atmosphere is required. Additionally, no fluorinated slianes and organic
solvents are involved, which is very beneficial for environment safety
and protection. Our findings conceivably stand out as a new tool to
fabricate organic–inorganic superhydrophobic surfaces with
strong durability and robustness for practical applications in oil
spill accidents and industrial sewage emission
Removal Characteristics of Dissolved Organic Nitrogen and Its Bioavailable Portion in a Postdenitrifying Biofilter: Effect of the C/N Ratio
Addition of external carbon sources
to postdenitrification biofilters
(DNFs) is frequently used in municipal wastewater treatment plants
to enhance dissolved inorganic nitrogen removal. However, little is
known about its influence on the removal of dissolved organic nitrogen
(DON). This study investigated the effect of the carbon-to-nitrogen
(C/N) ratio (3, 4, 5, and 6) on the removal characteristics of DON
and bioavailable DON (ABDON) in the pilot-scale DNFs treating real
secondary effluent. Results showed that DNFs effluent DON accounted
for 31.2–39.8% of the effluent total nitrogen. The maximum
effluent DON and ABDON concentrations both occurred in DNF operated
at a C/N ratio of 3. There was no significant difference in effluent
DON concentrations in DNFs at C/N ratios of 4, 5, and 6; however,
effluent ABDON and DON bioavailability significantly decreased with
C/N ratios (<i>p</i> < 0.05, <i>t</i>-test).
According to the chemical composition analysis, effluent DON at high
C/N ratios tends to contain less % molecular weight < 1 kDa nitrogenous
organic compounds and proteins/amino sugars-like nitrogenous organic
formulas, which is likely responsible for its low bioavailability.
Overall, this study indicates the benefit of a high C/N ratio during
the DNF process in terms of controlling the DON forms that readily
stimulate algal growth