Metal nanoparticle preparation within modifiable p(4-VP) microgels and their use in hydrogen production from NaBH4 hydrolysis

Composite poly(4-vinyl pyridine)-silica (p(4-VP)–Si) nanoparticles were synthesized, employing trimethoxy vinyl silane (TMVS) as silica forming agent using ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and ammonium persulfate (APS) as the initiator in an oil-in-water micro emulsion system. Porous p(4-VP) nanoparticles were generated from p(4-VP)–Si by treatment with hydrofluoric acid (HF). The size of p(4-VP)-based particles ranged between 300 and 500 nm. The porous p(4-VP) particles have a surface area of 42.26 m²/g. We also report preparation of various metal nanoparticles, such as Co and Ni, inside bare p(4-VP), p(4-VP)–Si and porous p(4-VP) nanoparticles by absorption from the corresponding metal ions aqueous solution and then reduction with NaBH₄. Atomic Absorption Spectroscopy (AAS) was used to determine the metal particle content of the p(4-VP)-based nanoparticles. The hydrogen production rate of Co-containing p(4-VP) was found to be superior to Ni-containing p(4-VP) under the same conditions. Cobalt-containing p(4-VP)–Si and porous p(4-VP) microgel composites can generate hydrogen faster than Co-containing p(4-VP). Moreover, p(4-VP)-based microgels showed seven fold hydrogen production rate, and almost five fold turn over frequency (TOF) than p(AMPS) microgels in terms of catalytic performances reported earlier.     

Efficient polymer solar cells based on dialkoxynaphthalene and benzo[c][1,2,5]thiadiazole: A new approach for simple donor-acceptor pair

We reported the synthesis of novel polymeric semiconductor materials based on [poly(4-(5-(1,5-bis(alkoxy)naphthalen-2-yl)thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole)] (PANTBT) and the fabrication of solar cells with a power conversion efficiency of 4.2% using the synthesized polymers blended with [6,6]-phenyl C₇₁ butyric acid methyl ester (PC₇₀BM) in bulk heterojunction geometry. By varying the side chains, three polymers were synthesized [poly(4-(5-(1,5-bis(2-ethylhexyloxy)naphthalen-2-yl)thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole)] (PENTBT), [poly(4-(5-(1,5-bis(decyloxy)naphthalen-2-yl)thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole)] (PDNTBT), and [poly(4-(5-(1,5-bis(tetradecyloxy)naphthalen-2-yl)thiophen-2-yl)-7-(thiophen-2-yl)benzo[c][1,2,5]thiadiazole)] (PTDNTBT), maintaining a low highest occupied molecular orbital (HOMO) energy level and relatively low band gap, which lead to a high open circuit voltage and short circuit current of the resulting devices. Due to the superior miscibility of PANTBT derivatives with PC₇₀BM, favorable phase separation with a domain size of 10-20 nm was achieved regardless of the crystalline nature of the pristine polymers. PDNTBT with alkyl side chain C10 and PTDNTBT with alkyl side chain C14 showed higher photovoltaic performances. In addition, the effects of the crystalline nature of polymers on the thermal stability of the resulting solar cell devices were discussed in terms of the influence of side chains.     

Electrosyntheses, characterizations and electrochromic properties of a copolymer based on 4,4′-di(N-carbazoyl)biphenyl and 2,2′-bithiophene

Electrochemical copolymerization of 4,4′-di(N-carbazoyl)biphenyl (CBP) with 2,2′-bithiophene (BT) is carried out in acetonitrile (ACN)/dichloromethane (DCM) (1:1, by volume) solution containing sodium perchlorate (NaClO₄) as a supporting electrolyte. Characterizations of the resulting copolymer P(CBP-co-BT) are performed by cyclic voltammetry (CV), UV-vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetry (TG). The P(CBP-co-BT) film has distinct electrochromic properties and exhibits four different colors (orange yellow, blue, yellowish green and greenish blue) under various potentials. Maximum contrast (ΔT%) and response time of the copolymer film are measured as 51.6% and 0.94 s at 667 nm. An electrochromic device (ECD) based on P(CBP-co-BT) and poly(3,4-ethylenedioxythiophene) (PEDOT) is constructed and characterized. The optical contrast (ΔT%) at 700 nm is found to be 28.6% and the response time is measured as 0.47 s. The coloration efficiency (CE) of the device is calculated to be 234 cm² C⁻¹ at 700 nm. An ECD also has good optical memories and redox stability.     

Prospect Evaluation of Low-GWP Refrigerants R1233zd(E) and R1336mzz(Z) Used in Solar-Driven Ejector-Vapor Compression Hybrid Refrigeration System

In this paper, the entrainment ratio, pump work, heat loads of heat exchangers and COPthermal were theoretically evaluated for a solar-driven ejector-vapor compression hybrid refrigeration system with R1233 zd(E) and R1336 mzz(Z) as the working fluids. The evaluation of the utilization potentials of R1233 zd(E) and R1336 mzz(Z) was presented by comparing the system performance with that of R245 fa, a commonly used refrigerant in the ejector system. The results indicated that the systems with R1233 zd(E) and R1336 mzz(Z) had a higher entrainment ratio and lower pump work. The pump works when using R1233 zd(E) and R1336 mzz(Z) can be up to 14.59% and 38.05% lower than those of R245 fa, respectively. Meanwhile, the system showed the highest COP_(thermal) utilizing R1233 zd(E) followed by that of R245 fa, with the R1336 mzz(Z) system having the lowest value. The differences between R1233 zd(E) and R1336 mzz(Z) systems, R1233 zd(E) and R245 fa systems were 4.33% and 2.0%, respectively. This paper was expected to provide a good reference for the utilizing prospect of R1233 zd(E) and R1336 mzz(Z) in ejector refrigeration systems.     

SOCIO-ECONOMIC ASPECTS OF THE AUSTRIAN 200 kWp-PHOTOVOLTAIC-ROOFTOP PROGRAMME

Between 1992 and 1994 a 200 kWp-rooftop programme to promote small grid-connected Photovoltaic (PV) systems was conducted in Austria. Within this programme about 100 PV systems with an average capacity of 2.28 kWp were installed. This paper investigates the socio-economic aspects of this programme and the prospects for a further dissemination of this technology. The major conclusions of this investigation are as follows: (1) The motives to invest in a PV system are: (i) environmental protection; (ii) an alternative to nuclear power; (iii) technical interest. Yet, it is also important that the public supports this purchase by means providing subsidies. (2) The purchase of a PV system leads to different changes in consumer behaviour. Consumers with low initial consumption increased their electricity demand slightly, while the majority of consumers with high initial electricity demand saved electricity. (3) The financial incentives in the programme were not optimally designed. With the same amount of total subsidies it would have been possible to promote more PV systems. (4) The key factors for a further dissemination of PV systems are: (i) financial incentives; (ii) a reduction of the investment costs; (iii) increase in reliability; (iv) distribution of information; (v) enhancement of environmental awareness.     

电活性双酚A的合成及其锂离子电池防过充性能研究

对双酚A进行结构修饰,经甲醚化、氰基取代,设计合成了2,2-双-(4-(β-氰基乙氧基)苯基)丙烷（DBDCN）、2-(4-(β-氰基乙氧基)苯基)-2'-(4-甲氧基苯基)丙烷（DBMCN）和2,2-双-(4-甲氧基苯基)丙烷（DBMB）,将三种化合物作为锂离子电池的防过充添加剂开展研究。在锂离子电池电解液1 mol/L LiPF₆/[碳酸乙烯酯（EC）+ 碳酸二乙酯（DEC） + 碳酸甲乙酯（EMC） （1∶1∶1,体积比）]中分别添加0.1 mol/L的DBDCN、DBMB和DBMCN,采用循环伏安、过充测试、电化学阻抗、恒流充放电和扫描电子显微镜等手段研究DBDCN、DBMB和DBMCN的防过充性能,并探讨添加剂与正极材料LiFePO₄的相容性。这些化合物的氧化还原电位均为4.1 V,显著提高了电池的过充保护。100%过充测试和5 V截止电压测试结果表明,DBMB的防过充性能明显优于DBDCN和DBMCN。以0.5 C倍率电流循环100圈,基础电解液和分别添加0.1 M DBDCN、DBMB、DBMCN的电池放电比容量分别为134.5 mA∙h/g、135.3 mA∙h/g、132.8 mA∙h/g和127.0 mA∙h/g,容量保持率分别为87.7%、87.0%、89.5%和84.3%。结果表明,DBMB对电池防过充作用最明显。     

Composites of platinum particles embedded into poly(6-cyanoindole)/poly(styrenesulfonic acid) for methanol oxidation

Poly(6-cyanoindole) (P(CnId)) is blended with poly(styrenesulfonic acid) via doping periods of 1, 10, 20, and 30 s to obtain P(CnId)–1PSS, P(CnId)–10PSS, P(CnId)–20PSS, and P(CnId)–30PSS electrodes, respectively. FT-IR studies have revealed that P(CnId) is doped with PSS. Pt particles can be doped into P(CnId)–1PSS, P(CnId)–10PSS, P(CnId)–20PSS, and P(CnId)–30PSS by chronocoulometry (0.15 C) using electrodeposition to acquire P(CnId)–1PSS–Pt, P(CnId)–10PSS–Pt, P(CnId)–20PSS–Pt, and P(CnId)–30PSS–Pt films, respectively. For comparative purposes, in this study, Pt particles were deposited into P(CnId) under the same conditions. Scanning electron microscopy (SEM) characterization revealed that platinum distributes more uniformly into the as-prepared P(CnId)–10PSS films. The anodic peak currents could be clearly observed to reach the saturation point at a methanol concentration larger than 0.8 M. A large electrocatalytic current towards methanol oxidation (27 mA cm^?2 mg^?1) was noticed in P(CnId)–10PSS–Pt electrodes in comparison to P(CnId)–Pt without PSS (6.3 mA cm^?2 mg^?1) at +0.86 V (vs. RHE), indicating that the P(CnId)–10PSS–Pt electrode reveals potential applicability as an electrocatalyst support.     

Phosphoric acid doped sulfonated poly(tetra phenyl isoquinoline ether sulfone) copolymers for high temperature proton exchange membrane potential application

Phosphoric acid-doped sulfonated poly(tetra phenyl isoquinoline ether sulfone)s (PA-SPTPIESs) were successfully synthesized for high temperature proton exchange membrane. Poly(tetra phenyl ether ketone sulfone)s (PTPEKS) were prepared from 1,2-bis(4-fluorobenzoyl)-3,4,5,6-tetraphenyl benzene (BFBTPB) and bis(4-fluorohenyl) sulfone with bis(4-hydroxyphenyl) sulfone. The synthesis of the poly(tetra phenyl isoquinoline ether sulfone)s (PTPIESs), was carried out via an intramolecular ring-closure reaction of dibenzoylbenzene of PTPEKS with benzylamine. The sulfonated poly(tetra phenyl isoquinoline ether sulfone)s (SPTPIESs) were obtained by following sulfonation with concentrated sulfuric acid and doped by phosphoric acid. Different contents of sulfonated unit on PTPIESs (8, 12, 16 mol% of BFBTPB) and PA-SPTPIESs were studied by FT-IR, ¹H NMR spectroscopy, and thermogravimetric analysis (TGA). Strong acid–base interaction effect between poly benzisoquinoline (PBI) and sulfonic acid groups formed ionic crosslinking network between polymer chains. The ion exchange capacity (IEC) and proton conductivity of PA-SPTPIESs were evaluated with degree of sulfonation and doping of phosphoric acid.     

On the physics of hydrogen plastification and superplasticity of metallic materials and compounds

Micromechanisms are considered as the so called “mechanical instability” (Int. Sci. J. Alternative Energ. Ecol. 2 (2002) 36) of some solids (metallic materials and compounds) in hydrogen atmosphere or under electrolytic hydrogen charging (with respect to a sharp decreasing of their shear modulus, without a considerable change of their elastic modulus), on the basis of an analysis of the related experimental data, viz., a series of works on a sharp decrease of flow stress of iron mono- and poly-crystals under electrolytic hydrogen charging (loading) (Bull. Jpn. Inst. Metal. 21 (1982) 26), works on anomalous plastic auto-deformation of iron under thermo-cycling around temperature of α⇔γ transformation in hydrogen atmosphere (the hydrogen superplasticity) (Phys. Met. Metallogr. 55 (1983) 805), works on “a deformation response” (as a sharp plastification) of solids (metals (Pd, V, Ta, Nb, Zr), amorphous Fe- and Co-based alloys, intermetallics (TiNi) and Laves phases) (Phys. Met. Metallogr. 81 (1996) 167; Phys. Met. Metallogr. 83 (1997) 139), works on the hydrogen amorphization of Zr₃Rh type compounds (Yen et al.), works about high-pressure hydrogen influence on plasticity, strength and cyclic fatigue of steels (Workableness of steels and alloys in hydrogen environments, Livov, Ukraine, 1999), and also a plenty of the known works on the hydrogen plastification and superplasticity of titanium alloys (B.A. Kolachev and others), and particularly, TiAl intermetallics (Phys. Chem. Mater. Treat. 5 (1997) 101).     

SOFC阳极原始粉末制备工艺对阳极片微结构和电性能的影响

固体氧化物燃料电池(SOFC)的阳极是燃料氧化反应的场所,是SOFC的重要组成部分.然而具有较好催化活性的Ni-SDC阳极的制备目前普遍采用的是NiO与Ce0.8Sm0.2O1.9(SDC)混合的方法,即外加法,很少有用内加法同时制备出包含有NiO与SDC的NiO-SDC粉体.阳极材料的加工方法有可能会对Ni-SDC阳极性能产生大的影响,很有研究的必要.采用柠檬酸-硝酸盐溶胶-凝胶低温自蔓延燃烧法分别制备了NiO、SDC、NiO-SDC(质量比NiO∶SDC=1∶1)和Co3O4-NiO-SDC(质量比Co3O4∶NiO∶SDC=1∶1∶2)粉末,采用X射线衍射仪(XRD)检测了粉体的成相情况.将单独制备的NiO与SDC粉末按质量比为1∶1制成阳极片a,NiO-SDC粉末和Co3O4-NiO-SDC粉末也分别制成了阳极片b和阳极片c.并采用四端子法测量了其电导率值.分析了电导率与原始粉体制备工艺及阳极片的微结构之间的关系.结果显示,用上述方法合成的粉体成相很好,阳极片的电导率与微结构有极强的联系,微结构则受其原始粉末制备工艺和组成的强烈影响.     

Optimization of municipal solid waste (MSW) disposal in Saudi Arabia

Municipal solid waste (MSW) mainly comprises organics, paper, glass, plastics, metals, wood, etc. Rapid industrialization, high population growth rate, and fast urbanization have resulted in increased levels of pollution and MSW in Saudi Arabia. The amount of waste has been steadily increasing due to increasing human population and urbanization. Recovery refers to materials removed from the waste stream for the purpose of recycling and/or composting. There are various options available to convert solid waste to energy. Mainly, the following types of technologies are available: (1) sanitary landfill, (2) incineration, (3) pyrolysis, (4) gasification, and (5) anaerobic digestion. An integrated MSW disposal policy comprises (1) reduction of MSW source, (2) reuse of MSW, (3) recycling of MSW, (4) landfill and gas-to-energy conversion, and (5) MSW-to-energy conversion. Traditionally, MSWs have been disposed in landfills. Landfill is the most inexpensive waste disposal option. The main MSW disposal policies and barriers have been concluded in this study.     

Optical properties of high-quality CuGaSe2 epitaxial layers examined by piezoelectric photoacoustic spectroscopy

The piezoelectric photoacoustic (PPA) signals for Cu-rich CuGaSe₂ (CGS) /GaAs (0 0 1) epitaxial layer (Cu/Ga=1.09–2.16) grown by molecular beam epitaxy (MBE) were successfully obtained at liquid-nitrogen temperature. The bandgap energies of CGS (A-band) decreased and GaAs was not almost changed with increasing the Cu/Ga ratios. This phenomenon was very similar to that of free exciton (FE) by photoluminescence (PL) and the lattice parameter c by X-ray diffraction (XRD) measurements.     

Construction of Co(OH)F/Ni(OH)2@Fe(OH)3 core-shell heterojunction on nickel foam for efficient oxygen evolution

The sluggish anodic reaction (OER) kinetics hinder electrochemical water splitting at high energy densities, which can be solved by developing suitable catalysts. Herein, we report a novel Co(OH)F/Ni(OH)₂@Fe(OH)₃-D_x (D_x represents the hydrolysis time, X = 0.5, 1, 2 days) heterojunction grown on nickel foam, which was synthesized by the hydrolysis of Fe³⁺ on the Co(OH)F/Ni(OH)₂ surface at room temperature. Electrocatalytic oxygen evolution tests showed that the prepared Co(OH)F/Ni(OH)₂@Fe(OH)₃-D_x composites had better catalytic activity than pure Co(OH)F/Ni(OH)₂ in 1.0 M KOH, especially Co(OH)F/Ni(OH)₂@Fe(OH)₃-D₁. It only requires an ultra-low overpotential (η₁₀) of 270 mV, SEM and TEM showed that Co(OH)F/Ni(OH)₂@Fe(OH)₃-D₁ is a perfect all-encapsulated core-shell structure, which facilitates the exposure of active sites and electron transfer, and thus obviously improves oxygen evolution.     

Bis (dibenzylidene acetone) palladium (0) catalyst for glycerol oxidation in half cell and in alkaline direct glycerol fuel cell

In this study, catalytic activity and performance of bis (dibenzylidene acetone) palladium (0) catalyst, Pd (DBA)₂, was evaluated toward glycerol oxidation reaction (GOR) in alkaline half cell and alkaline direct glycerol fuel cell (DGFC). The electrooxidation of glycerol on Pd (DBA)₂ was characterized in half cell by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) techniques. Obtained results have highlighted the excellent electrocatalyst activity of Pd (DBA)₂ in terms of specific peak current density and onset potential compared to the results obtained by conventional Pd base catalysts. CVs results also demonstrate that Pd (DBA)₂ is still active even after 200 cycles.     

Systemic approach for techno-economic evaluation of triple hybrid (RO,MSF and power generation) scheme including accounting of CO2 emission

A system of models for the techno-economic evaluation of a triple hybrid, reverse osmosis (RO), multistage flush (MSF) and power generation process has been developed. There are three groups of models underlying the system: (A) models describing power-generating technology; (B) models describing RO desalination, and (C) models describing MSF desalination. Any group of individual models, in turn, consists of a set of submodels of different hierarchy levels; they are: (1) technological submodel, (2) fuel or energy submodel, (3) ecological submodel and (4) economic submodel. (1) The technological submodel is focused on the calculation of technological characteristics at different operating loads of the generating systems; (2) the fuel or energy submodel covers the calculation of fuel influx into power-generating systems at different operating loads; (3) the ecological submodel focuses on estimation of CO₂ emissions at different operating regimes; (4) the economic submodel gives values of economic indicators, such as (a) cost of water, (b) cost of energy, and (c) accounting for CO₂ emissions through imposed carbon tax (assuming rates of environmental taxes recommended by European Union tax legislation). This paper contains an analysis of the behavior of economic and ecological indicators for various technological parameters and economic assumptions, such as (1) load, specific fuel consumption and efficiency of the energy generating system, (2) specific energy consumption for desalination, (3) specific emissions of CO₂, and (4) taxes on CO₂ emissions. The model presented can be applied for the analysis of schemes where seasonal surplus of unused power is utilized by RO which are characterized by higher efficiency of fuel consumption and decreasing specific CO₂ emissions.     

Investigation on available wind energy at Tungku beach

In this paper, wind velocities and directions (sea and land) are recorded in different days and times. The data collected were compared with the weather data from the Brunei Darussalam Meteorological Service (BDMS) and the findings of other researchers and were found to be in good agreement. The potential of wind energy is predicted from the available data collected. The average generated power (forenoon and afternoon) is found to be 25 (mean) and 18 W (median), 101 (mean) and 73 W (median), 912 (mean) and 660 W (median), 10137 (mean) and 7331 W (median) for a rotor with a diameter of 2.5, 5, 15 and 50 m, respectively. The power density P_d for wind farming is found to be 0.26 (mean) and 0.19 (median), 0.31 (mean) and 0.22 (median) for the rotor whose diameter is 2.5 and 50 m, respectively, while the average P_d values are found to be 0.28 (mean) and 0.2 (median) for the rotor whose diameter is 5 and 15 m.     

Electrical/electronic effects of titanium and iron impurities in EFG and FZ solar cell silicon: SPV/EBIC analysis

In this paper results on surface photovoltage (SPV) and electron beam induced conductivity (EBIC) studies of edge-defined film-fed growth (EFG) and floating zone (FZ) silicon solar cell materials (both p-type) are presented. A systematic comparison based on minority carrier diffusion length and carrier recombination is made between: (i) samples contaminated with Ti and/or Fe, (ii) samples gettered by phosphorous diffusion, and (iii) as-received samples. Deep level transient spectroscopy (DLTS) measurements, together with the iron-boron (FeB) pairing kinetics [1] have successfully been used to detect the presence of Fe in the samples. Even though this process is effective in revealing Fe impurities in p-type FZ silicon it is evidently not suitable for Fe identification in p-type EFG silicon. Ti, like Fe, is found to be a prominent lifetime-limiting metallic impurity in both EFG and FZ silicon. Phosphorous diffusion is proven to be an effective external gettering technique for fast-diffusing impurities such as Fe, but not for Ti.     

Risk-averse stochastic operation of a power system integrated with hydrogen storage system and wind generation in the presence of demand response program

Wind generation (WG) units as renewable energy sources (RESs) are increasing in the world due to environmental functions and lack of conventional energy sources. Also, hydrogen storage system (HSS) as an energy storage system (ESS) is used to cope with variable nature of RESs in which the concepts of power to hydrogen (P2H) and hydrogen to power (H2P) are defined. In this work, a risk-averse stochastic operation of HSS and WG is modeled using a scenario-based stochastic approach by considering price-responsive demand response (DR) program. All uncertainties are modeled via a scenario-based stochastic approach while the risk related uncertainties are modeled via the downside risk constraints (DRC) to capture the risk-averse operation of the HSS and WG. In order to investigate the impact of DRC implementation, a risk-averse strategy is compared versus risk-neutral strategy. Compared results show that the risk-in-cost (RIC) is reduced while the expected operation cost (EOC) is raised to deal with the risk of the uncertainty.     

Uncovering the multiple objectives behind national energy efficiency planning

This work seeks to identify the fundamental objectives behind the development of energy efficiency (EE) plans for countries. It also presents a method to quantify the degree of achievement of each objective, through the identification and operationalization of attributes. This was achieved by applying Keeney's value-focused thinking approach. For that purpose, three key decision makers in EE planning were interviewed along with a bibliographic review on the subject. From this process six fundamental objectives were identified formalizing the problem as a multi-objective one: (i) to minimize the influence of energy use on climate change; (ii) to minimize the financial risk from the investment; (iii) to maximize the security of energy supply; (iv) to minimize investment costs; (v) to minimize the impacts of building new power plants and transmission infrastructures and (vi) to maximize the local air quality. The respective attributes were: (i) CO₂ emissions savings; (ii) payback; (iii) imported energy savings; (iv) investment cost; (v) electricity savings; and (vi) total suspended particles savings. To show the usefulness of the work, the objectives and attributes identified were used to show the possible outcomes from five hypothetical EE plans for Portugal.     

Applications of artificial neural networks for refrigeration, air-conditioning and heat pump systems—A review

In this paper, an attempt has been made to review the applications of artificial neural networks (ANN) for energy and exergy analysis of refrigeration, air conditioning and heat pump (RACHP) systems. The studies reported are categorized into eight groups as follows: (i) vapour compression systems (ii) RACHP systems components, (iii) vapour absorption systems, (iv) prediction of refrigerant properties (v) control of RACHP systems, (vi) phase change characteristics of refrigerants, (vii) heat ventilation air conditioning (HVAC) systems and (viii) other special purpose heating and cooling applications. More than 90 published articles in this area are reviewed. Additionally, the limitations with ANN models are highlighted. This paper concludes that ANN can be successfully applied in the field of RACHP systems with acceptable accuracy.