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Prediction of future materials, maintenance and waste recovery costs on photovoltaics solar panels
No full textPetroleum and natural gas are mainly used to generate electricity nowadays. However, the emission of greenhouse gas is a concern, and is getting serious year by year. In order to protect our environment, it is imperative to replace the rapid uses of fossil fuel with alternative or renewable energy. Regarding the situation in Hong Kong, if the government want to increase the use rate of solar energy in the long run, the cost is one of the major concerns. Detail knowledge of solar energy cost on the basis of the analysis on materials, duration, maintenance and waste recovery cost are thus necessary. The present study on the cost prediction of solar panel provides an insight on whether solar panels are sustainable in terms of low opportunity cost. The second generation of solar panel material has a lower cost than first generation given the fact that the both generations can have the same lifespan. In addition, the maintenance and duration time of the second generation are also satisfactory. Nevertheless, the waste recovery on the solar panel still need to be improved to achieve highly sustainable to maintain at a low cost. The cost analysis is an important parameter to encourage the citizens to use solar panel for electricity generation particularly after the newly launched feed-in tariff scheme in Hong Kong. Hong Kong nowadays are still more dependent on coal and natural gas to generate electricity energy due to the relative low cost, thus maintaining the solar panel at low and competitive cost promotes the widespread uses of solar energy in future
Reduction of RuVI(N) to RuIII-NH3 by Cysteine in Aqueous Solution
No full textThe reduction of metal nitride to ammonia is a key step in biological and chemical nitrogen fixation. We report herein the facile reduction of a ruthenium(VI) nitride complex [(L)RuVI(N)(OH2)]+ (1, L = N,N′-bis(salicylidene)- o-cyclohexyldiamine dianion) to [(L)RuIII(NH3)(OH2)]+ by Lcysteine (Cys), an ubiquitous biological reductant, in aqueous solution. At pH 1.0−5.3, the reaction has the following stoichiometry: [(L)RuVI(N)(OH2)]+ + 3HSCH2CH(NH3)CO2 → [(L)RuIII(NH3)(OH2)]+ + 1.5(SCH2CH(NH3)CO2)2. Kinetic studies show that at pH 1 the reaction consists of two phases, while at pH 5 there are three distinct phases. For all phases the rate law is rate = k2[1][Cys]. Studies on the effects of acidity indicate that both HSCH2CH(NH3 +)CO2 – and −SCH2CH(NH3 +)CO2 − are kinetically active species. At pH 1, the reaction is proposed to go through [(L)- RuIV(NHSCH2CHNH3CO2H)(OH2)]2+ (2a), [(L)RuIII(NH2SCH2CHNH3CO2H)(OH2)]2+ (3), and [(L)RuIV(NH2)(OH2)]+ (4) intermediates. On the other hand, at pH around 5, the proposed intermediates are [(L)RuIV(NHSCH2CHNH3CO2)- (OH2)]+ (2b) and [(L)RuIV(NH2)(OH2)]+ (4). The intermediate ruthenium(IV) sulfilamido species, [(L)- RuIV(NHSCH2CHNH3CO2H)(OH2)]2+ (2a) and the final ruthenium(III) ammine species, [(L)RuIII(NH3)(MeOH)]+ (5) (where H2O was replaced by MeOH) have been isolated and characterized by various spectroscopic methods
1 Ingredient 6 Ways 六種變化
Get PDFChickpea choices
百變鷹嘴豆
With a rising demand for Middle Eastern dishes and the popularity of meat-free diets, the humble chickpea is becoming a much-favoured food. The protein-packed, fibre-filled pea-also known as gram or garbanzo and a member of the legume family-lends itself to a number of delectable culinary creations
中東美食熱潮方興未艾，加上素食風氣日盛，廉宜平凡的鷹嘴豆也因此風行起來。鷹嘴豆屬於豆莢科，含有豐富的蛋白質和膳食纖維， 是許多滋味佳餚的主要食材之
Frequency Island and Nonlinear Vibrating Systems
No full textPiecewise linear vibration isolator system is one of the development to introduce dual rate stiffness and damping. There are several vibrating behavior if the system is designed properly. Analytical treatment of the system determines some difficulties such as jump. This investigation indicates that such strong non-linear systems have a new phenomenon called Frequency Island in their fre-quency Response plot. Frequency Island is a possible isolated frequency Response that the vibrating system may jump into the island and stays there until the exci-tation frequency moves out of the range of the island. In this student existence, appearance, growing and disappearing of frequency is-land will be studied and examined. Frequency Island corresponds to large am-plitude vibration for certain range of system parameters and considered as a dan-gerous phenomena in real system. As a result, understanding its appearance will help designers and engineers to design the system to avoid Frequency Island
Reduction of RuVIºN to RuIII-NH3 by Cysteine in Aqueous Solution
No full textThe reduction of metal nitride to ammonia is a key step in biological and chemical nitrogen fixation. We report herein the facile reduction of a ruthenium(VI) nitrido complex [(L)RuVI(N)(OH2)]+ (1, L = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) to [(L)RuIII(NH3)(OH2)]+ by l-cysteine (Cys), an ubiquitous biological reductant, in aqueous solution. At pH 1.0–5.3, the reaction has the following stoichiometry: [(L)RuVI(N)(OH2)]+ + 3HSCH2CH(NH3)CO2 → [(L)RuIII(NH3)(OH2)]+ + 1.5(SCH2CH(NH3)CO2)2. Kinetic studies show that at pH 1 the reaction consists of two phases, while at pH 5 there are three distinct phases. For all phases the rate law is rate = k2[1][Cys]. Studies on the effects of acidity indicate that both HSCH2CH(NH3+)CO2– and –SCH2CH(NH3+)CO2– are kinetically active species. At pH 1, the reaction is proposed to go through [(L)RuIV(NHSCH2CHNH3CO2H)(OH2)]2+ (2a), [(L)RuIII(NH2SCH2CHNH3CO2H)(OH2)]2+ (3), and [(L)RuIV(NH2)(OH2)]+ (4) intermediates. On the other hand, at pH around 5, the proposed intermediates are [(L)RuIV(NHSCH2CHNH3CO2)(OH2)]+ (2b) and [(L)RuIV(NH2)(OH2)]+ (4). The intermediate ruthenium(IV) sulfilamido species, [(L)RuIV(NHSCH2CHNH3CO2H)(OH2)]2+ (2a) and the final ruthenium(III) ammine species, [(L)RuIII(NH3)(MeOH)]+ (5) (where H2O was replaced by MeOH) have been isolated and characterized by various spectroscopic methods
Comparative study of on-off control and novel high- low control of regenerative indirect evaporative cooler (RIEC).
No full textThe main characteristic of an indirect evaporative cooler (IEC) is its dependency on ambient air conditions. To ensure stable indoor temperature and provide better thermal comfort for the occupants, proper control strategy is essential. However, very limited studies report the controller used in IEC. Therefore, two control schemes are comparatively studied for regenerative indirect evaporative cooler (RIEC) application, including conventional on-off control and newly proposed high-low (H-L) control. Under on-off control scheme, the fans are either in operation at constant rated speeds or turned off if the indoor temperature is satisfied. While under H-L control scheme, the fans would be switched between high speed and low speed rather than completely turned off. The annual performance of RIEC was simulated under the two control schemes based on the RIEC model and dynamic indoor heat and mass balance model. The results show that the H-L control is superior to on-off control by providing better thermal comfort, better indoor air quality and 11.3% less energy consumption annually. The advantages of H-L control are mainly reflected in transition seasons with smaller indoor temperature variation range, lower switch frequency of the fan speed, smaller predicted mean vote (PMV) variation and longer fresh air guarantee
A new capacity controller for a direct expansion air conditioning system for operational safety and efficiency.
No full textFor achieving a balance between the operational safety and efficiency of a variable speed direct expansion air conditioning system, a new capacity controller that can not only simultaneously control indoor air temperature and humidity, but also select an optimized degree of superheat setting to properly balance the operational safety and efficiency has been developed, by adding a control module to a previously developed capacity controller. The core of the control module was an artificial neural network based model representing the known relationship between the inherent operational characteristics and operational stability of a variable speed direct expansion air conditioning system. Using the control module developed, the degree of superheat setting could be varied in accordance with the variation in operating conditions for ensuring a safe and an efficient operation. The performance of the new capacity controller was experimentally tested using an experimental variable speed direct expansion air conditioning system. Controllability test results showed that the system hunting was mitigated when a larger degree of superheat setting was selected by the developed control module and an improvement in COP at about 3.4% was achieved when a smaller one was selected when using the new capacity controller for simultaneously controlling indoor air temperature and humidity. Practical application: This paper reports a new capacity for a VS DX A/C system, which can not only control indoor air temperature and humidity through varying compressor and supply fan speeds, but also select an optimized DS setting for ensuring both a safe and efficient system operation. The controllability test results showed that the new capacity controller could be applied to DX A/C systems for indoor thermal control with a higher operational safety and energy efficienc
Investigation on the regeneration and corrosion characteristics of an anodized aluminum plate regenerator.
No full textThe traditional vapor compression cooling system (VCS) has been criticized for its heavy reliance on electricity consumption and limited control ability of humidity. Compared with the VCS, the liquid desiccant cooling system (LDCS) is more efficient by handling the sensible and latent load separately. The present study investigated the regeneration and corrosion characteristics of an anodized aluminum plate regenerator for the first time. Comparative tests were conducted to present the regeneration and corrosion characteristics of the normal and anodized regenerator. The influence of internal heating on the regeneration performance was also identified. The results showed that the corrosion rate was reduced from 0.0005218 mm/year for normal aluminum to 0.000011 m/year for anodized one under the same operating conditions. However, pitting corrosion was observed at operating conditions with high solution temperature, as the anodized layer of anodized aluminum was damaged due to the high temperature. Compared with the normal aluminum regenerator, the anodized one had an average enhancement of 24% and 23.7% in terms of regeneration rate and effectiveness, respectively. It was attributed to the increment of surface energy from 26.4 mN/m for normal aluminum to 47.6 mN/m for anodized plate. Besides, it was found that, compared with adiabatic one, the internally-heated regenerator improved the regeneration rate by 6.0%~38% and the regeneration effectiveness by 6.3%~32% depending on the operating conditions. The advantage of present study is that it can guide the design of anodized aluminum regenerator for LDCS