Interfacial photo‐vapor conversion has been suggested as a cost‐effective and sustainable technology for seawater desalination. However, the conversion performance was still limited by some ...drawbacks, like salt accumulation and poor mechanical stability. Herein, a scalable MoS2‐based porous hydrogel (SMoS2‐PH) with good mechanical stability and salt resistance was successfully constructed through a crosslinking foaming polymerization method. With the high porosity (92.63 %), the SMoS2‐PH performed an impressive evaporation rate of 3.297 kg m−2 h−1 and photothermal conversion efficiency of 93.4 % under 1‐sun illumination. Most importantly, the SMoS2‐PH could maintain high and stable photothermal properties for 15 days on the surface of seawater. We believe that the excellent salt resistance, the high photothermal conversion efficiency, the ease of scale preparation method and the available commercial MoS2 make the SMoS2‐PH a promising device for full‐scale seawater desalination.
A scalable MoS2‐based porous hydrogel (SMoS2‐PH) was successfully constructed with a hydrophilic polyacrylamide as its skeleton and commercial MoS2 as the solar absorbent through a crosslinking foaming polymerization method. The SMoS2‐PH performed an impressive evaporation rate of 3.297 kg m−2 h−1 and solar‐to‐vapor conversion efficiency of 93.4 % under 1‐sun illumination.
•The merits and demerits of the different combustion modes are comprehensively discussed.•Effective strategies are systematically reviewed to overcome the limitations of the HCCI engine.•Ignition ...timing and combustion phase are still the main challenges for the HCCI engine application.•Combination strategies are proposed to optimize the auto-ignition timing and combustion phase.
Generally, the homogeneous charge compression ignition (HCCI) engine presents superior fuel economy and ultra-low NOx and particle matter emissions compared with the traditional combustion engine. However, the HCCI engine is essentially decoupled from the spark plug and fuel injection. That means the HCCI engine has no direct control mechanism for the auto-ignition timing and subsequent combustion phase. Without effective strategies to control the auto-ignition timing on time according to the operating conditions, the HCCI engine will be limited in a small operation range due to the cold start problem, high pressure rate and combustion noise, and even knocking combustion at the high-load. Generally, the properties of physical–chemical kinetics of fuels, as well as the mixture temperature spatial and temporal changing histories in the cylinder, strongly determine the ignition timing and affect the combustion phase in HCCI engine. Some effective techniques and controlling strategies, such as fuel management, homogeneous charge preparation, exhaust gas recirculation, etc. are widely used in the HCCI engine. These techniques and controlling strategies are used solely or conjunctively with each other to control the compressed gas temperature, pressure and mixture distribution in the cylinder at the end of the compression stroke so that the charge mixture could be auto-ignited at the desired crank angle, and thereby obtaining optimal combustion phase and heat release rate on a wide operation range for the HCCI engine. Thus, this paper comprehensively reviews different effective techniques and controlling strategies used in the HCCI engine, and also summarizes in the tables.
A novel three dimensional MnO2 modified biochar-based porous hydrogel (MBCG) was fabricated to overcome the low sorption capacity and difficulty in solid-liquid separation of biochar (BC) for Cd(II) ...and Pb(II) removal. BC was initially modified by a rapid redox reaction between KMnO4 and Mn(II) acetate, and then incorporated into a polyacrylamide gel network via a rapid and facile free-radical polymerization. A foaming method was deliberately introduced during the fabrication to establish interpenetrated porous structure inside the network. Various characterizations were employed to examine the morphology, porous structures, chemical compositions, and mechanical properties of the samples. Adsorption performance of MBCG on Cd(II) and Pb(II) (isotherms and kinetics) as well as its desorption and reusability were also investigated. The results indicated that MnO2 modified biochars (MBC) were successfully introduced and homogeneously distributed in the porous bulk hydrogel, endowing MBCG with more uniform pore structure, excellent thermostability, remarkable mechanic strength, and superior adsorption performance. The maximum Langmuir adsorption capacity on Cd(II) and Pb(II) is 84.76 and 70.90 mg g−1, respectively, which is comparable or even larger than that of MBC. More importantly, MBCG can be rapidly separated and easily regenerated with an excellent reusability, which could retain 92.1% and 80.5% of the initial adsorption capacities of Cd(II) and Pb(II) after five cycles. These new insights make MBCG an ideal candidate in practical applications in water treatment and soil remediation contaminated with various heavy metals.
3D MnO2 modified biochar-based porous polyacrylamide hydrogel with easy separation and excellent reusability was successfully fabricated for the effective removal of Cd(II) and Pb(II) in aqueous solution. Display omitted
•A 3D MnO2 modified biochar-based porous polyacrylamide gel (MBCG) was fabricated.•The incorporated MBC endows MBCG with enhanced physicochemical properties.•The porous structure equips MBCG with effective removal of Cd(II) and Pb(II).•The spent MBCG can be easily separated and shows an excellent reusability.
Breast cancer is the most common cancer in women worldwide. Accurate early diagnosis of breast cancer is critical in the management of the disease. Although mammogram screening has been widely used ...for breast cancer screening, high false-positive and false-negative rates and radiation from mammography have always been a concern. Over the last 20 years, the emergence of "omics" strategies has resulted in significant advances in the search for non-invasive biomarkers for breast cancer diagnosis at an early stage. Circulating carcinoma antigens, circulating tumor cells, circulating cell-free tumor nucleic acids (DNA or RNA), circulating microRNAs, and circulating extracellular vesicles in the peripheral blood, nipple aspirate fluid, sweat, urine, and tears, as well as volatile organic compounds in the breath, have emerged as potential non-invasive diagnostic biomarkers to supplement current clinical approaches to earlier detection of breast cancer. In this review, we summarize the current progress of research in these areas.
Building on Seymour Papert's view of empowering students by mastering programming, this study conceptualized programming empowerment as consisting of four components: meaningfulness, impact, creative ...self-efficacy, and programming self-efficacy. A sample of 287 primary school students in grades four to six completed a corresponding survey. Confirmatory factor analysis validated the proposed components of the programming empowerment instrument. A structural equation model indicated that students with greater interest in programming perceived it as more meaningful, had greater impact, had greater creative self-efficacy, and had greater programming self-efficacy. Also, students with attitudes toward collaboration that were more positive than others had greater creative self-efficacy. Boys showed more interest in programming than girls did. Students in higher grade levels than others viewed programming as less meaningful and had lower programming self-efficacy. These results support future studies that evaluate the impacts of interest-driven computational thinking and programming curricula with ample collaboration opportunities.
•Empowerment consists of meaningfulness, impact, creative and programming self-efficacy.•The study validated the programming empowerment instrument.•Students with greater interest in programming perceive greater empowerment.•Students with positive collaboration attitude have greater creative self-efficacy.•Students in senior grades viewed programming as less meaningful than junior grades.
This paper empirically tested eight key features of WHO guidelines to age-friendly community by surveying 211 informal caregivers and 402 self-care adults (aged 45 to 85 and above) in Malaysia. We ...examined the associations of these eight features with active aging and social connectedness through exploratory and confirmatory factor analyses. A structural model with satisfactory goodness-of-fit indices (CMIN/df = 1.11, RMSEA = 0.02, NFI = 0.97, TLI = 1.00, CFI = 1.00, and GFI = 0.96) indicates that transportation and housing, community support and health services, and outdoor spaces and buildings are statistically significant in creating an age-friendly environment. We found a statistically significant positive relationship between an age-friendly environment and active aging. This relationship is mediated by social connectedness. The results indicate that built environments such as accessible public transportations and housing, affordable and accessible healthcare services, and elderly friendly outdoor spaces and buildings have to be put into place before social environment in building an age-friendly environment. Otherwise, the structural barriers would hinder social interactions for the aged. The removal of the environmental barriers and improved public transportation services provide short-term solutions to meet the varied and growing needs of the older population.
The efficacy and safety of maternal tenofovir disoproxil fumarate (TDF) in reducing mother‐to‐infant hepatitis B virus (HBV) transmissions is not clearly understood. We conducted a prospective, ...multicenter trial and enrolled 118 hepatitis B surface antigen (HBsAg)– and hepatitis B e antigen–positive pregnant women with HBV DNA ≥7.5 log10 IU/mL. The mothers received no medication (control group, n = 56, HBV DNA 8.22 ± 0.39 log10 IU/mL) or TDF 300 mg daily (TDF group, n = 62, HBV DNA 8.18 ± 0.47 log10 IU/mL) from 30‐32 weeks of gestation until 1 month postpartum. Primary outcome was infant HBsAg at 6 months old. At delivery, the TDF group had lower maternal HBV DNA levels (4.29 ± 0.93 versus 8.10 ± 0.56 log10 IU/mL, P < 0.0001). Of the 121/123 newborns, the TDF group had lower rates of HBV DNA positivity at birth (6.15% versus 31.48%, P = 0.0003) and HBsAg positivity at 6 months old (1.54% versus 10.71%, P = 0.0481). Multivariate analysis revealed that the TDF group had lower risk (odds ratio = 0.10, P = 0.0434) and amniocentesis was associated with higher risk (odds ratio 6.82, P = 0.0220) of infant HBsAg positivity. The TDF group had less incidence of maternal alanine aminotransferase (ALT) levels above two times the upper limit of normal for ≥3 months (3.23% versus 14.29%, P = 0.0455), a lesser extent of postpartum elevations of ALT (P = 0.007), and a lower rate of ALT over five times the upper limit of normal (1.64% versus 14.29%, P = 0.0135) at 2 months postpartum. Maternal creatinine and creatinine kinase levels, rates of congenital anomaly, premature birth, and growth parameters in infants were comparable in both groups. At 12 months, one TDF‐group child newly developed HBsAg positivity, presumably due to postnatal infection and inefficient humoral responses to vaccines. Conclusions: Treatment with TDF for highly viremic mothers decreased infant HBV DNA at birth and infant HBsAg positivity at 6 months and ameliorated maternal ALT elevations. (Hepatology 2015;62:375–386
This paper introduces a parallel and distributed algorithm for solving the following minimization problem with linear constraints:
minimize
f
1
(
x
1
)
+
⋯
+
f
N
(
x
N
)
subject to
A
1
x
1
+
⋯
+
A
N
...x
N
=
c
,
x
1
∈
X
1
,
…
,
x
N
∈
X
N
,
where
N
≥
2
,
f
i
are convex functions,
A
i
are matrices, and
X
i
are feasible sets for variable
x
i
. Our algorithm extends the alternating direction method of multipliers (ADMM) and decomposes the original problem into
N
smaller subproblems and solves them in parallel at each iteration. This paper shows that the classic ADMM can be extended to the
N
-block Jacobi fashion and preserve convergence in the following two cases: (i) matrices
A
i
are mutually near-orthogonal and have full column-rank,
or
(ii) proximal terms are added to the
N
subproblems (but without any assumption on matrices
A
i
). In the latter case, certain proximal terms can let the subproblem be solved in more flexible and efficient ways. We show that
‖
x
k
+
1
-
x
k
‖
M
2
converges at a rate of
o
(1 /
k
) where
M
is a symmetric positive semi-definte matrix. Since the parameters used in the convergence analysis are conservative, we introduce a strategy for automatically tuning the parameters to substantially accelerate our algorithm in practice. We implemented our algorithm (for the case ii above) on Amazon EC2 and tested it on basis pursuit problems with >300 GB of distributed data. This is the first time that successfully solving a compressive sensing problem of such a large scale is reported.
The eventual fading and scrapping of lithium (Li)-ion batteries will result in the formation of a huge urban mine of spent batteries. Hydrometallurgy and further extraction/separation are effective ...ways in which to recover the valuable metal ions from such batteries. Herein, extraction and recovery of spent lithium cobalt oxide (LiCoO2) battery leach liquors using Cyphos IL-101 is proposed. Based on the optimization of extraction conditions, continuous circulating extraction, and thermodynamic analysis, Cyphos IL-101 effectively extracted cobalt (Co) ions with excellent stability and high extraction capacity (35.25 g/L). The separation factor of Co and Li (βCo/Li) was 102.11 in 0.5 M HCl at 60 °C under the optimal operation condition. Moreover, an increase in temperature increased Co extraction in the spent Li-ion battery leach liquors. The extractants before and after use were characterized using ultraviolet-visible (UV–Vis) absorption spectra, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra. The extraction mechanism of cobalt ions by Cyphos IL-101 was suggested as that cobalt transferred to the organic phase from the aqueous phase in the form of CoCl42−. 90.5% of Co and 86.2% of Li were recovered by precipitation after extraction separation in the forms of cobalt oxalate and lithium carbonate with the purity 87.4% and 74.2%. This suggested method might provide a promising strategy for recycling spent lithium cobalt oxide batteries.
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•Cyphos IL-101 was firstly used to recover the spent lithium cobalt oxide batteries.•Organic solvent was replaced by water to dilute the ionic liquid extractant.•The extractant demonstrated high extraction capacity and good stability.•Water was used as a stripping agent to replace acids.
Fiber Bragg grating (FBG) sensor has been considered as a reliable sensor for health monitoring of structural and geotechnical projects. Various types of FBG based sensors have been proposed in past ...few decades and employed for health monitoring of many geotechnical structures. This paper presents an overview of the recent development and application of FBG based sensors for health monitoring of several key geotechnical structures, including soil nail systems, slopes, and piles. Different sensor design, implementation and packaging methods, advantages and limitations of using FBG based sensors in different projects are reviewed. Comparative analysis of using two mathematical methods for the prediction of ground movement using FBG sensor data are also carried out. The two typical mathematical methods include Finite Difference Method (FDM) and Numerical Integration method (NIM). Possible technical challenges of applying FBG sensors for geotechnical monitoring are discussed.
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