Concept: Light fixture
To adapt commercial poultry production to a new scenario of energy savings and to develop specific practices for quail production aimed at reducing costs while maintaining or improving productivity, four experiments were conducted. In the first experiment, birds were allocated to four treatments (photoperiod duration): T1: 14L:10D; T2: 15L:9D; T3: 16L:8D; and T4: 17L:7D. In the second experiment, birds were subjected to four levels of brightness: T1: 5 lux; T2: 10 lux; T3: 15 lux; and T4: 22 lux (control). In the third experiment, four types of lamps were evaluated: T1: compact fluorescent lamp (color temperature: 6,500K); T2: compact fluorescent lamp (color temperature: 2,700K); T3: incandescent lamp; and T4: yellow LED. In the last experiment, four lighting programs were compared: T1: continuous program (control), in which there was a single photoperiod of 15 h; the other treatments consisted of intermittent lighting programs, as follows: T2: 1 h of light provided 1 h after dusk; T3: 1 h of light provided 2 h before dawn; T4: half an hour of light provided 1 h after dusk and half an hour of light provided 1.5 h before dawn. In each experiment, 1,296 Japanese quail were evaluated for four 28-d cycles, totaling 112 experimental days. A completely randomized experimental design of 4 treatments with 12 replicates of 27 birds each was applied in all trials. Performance and egg quality were evaluated in each experiment. Higher egg production and adequate egg quality, as well as energy savings, can be obtained with Japanese quail using compact fluorescent lamps or LEDs and a photoperiod of 15 h/d supplied using an intermittent lighting program, with 1 h of artificial light 2 h before dawn at a brightness of 5 lux.
Artificial lighting systems are transitioning from incandescent to compact fluorescent lamp (CFL) and light-emitting diode (LED) bulbs in response to the U.S. Energy Independence and Security Act and the EU Ecodesign Directive, which lead to energy savings and reduced greenhouse gas emissions. Although CFLs and LEDs are more energy-efficient than incandescent bulbs, they require more metal-containing components. There is uncertainty about the potential environmental impacts of these components and whether special provisions must be made for their disposal at the end of useful life. Therefore, the objective of this study is to analyze the resource depletion and toxicity potentials from the metals in incandescent, CFL and LED bulbs to complement the development of sustainable energy policy. We assessed the potentials by examining whether the lighting products are to be categorized as hazardous waste under existing U.S. federal and California state regulations and by applying life cycle impact-based and hazard-based assessment methods (note that “life cycle impact-based method” does not mean a general life cycle assessment (LCA) but rather the elements in LCA used to quantify toxicity potentials). We discovered that both CFL and LED bulbs are categorized as hazardous, due to excessive levels of lead (Pb) leachability (132 and 44 mg/L, respectively; regulatory limit: 5) and the high contents of copper (111,000 and 31,600 mg/kg, respectively; limit: 2500), lead (3860 mg/kg for the CFL bulb; limit: 1000), and zinc (34,500 mg/kg for the CFL bulb; limit: 5000), while the incandescent bulb is not hazardous (note that the results for CFL bulbs excluded mercury vapor not captured during sample preparation). The CFLs and LEDs have higher resource depletion and toxicity potentials than the incandescent bulb due primarily to the high aluminum, copper, gold, lead, silver, and zinc. Comparing the bulbs on an equivalent quantity basis with respect to the expected lifetimes of the bulbs, the CFLs and LEDs have 3 to 26 and 2 to 3 times higher potential impacts than the incandescent bulb, respectively. We conclude that in addition to enhancing energy efficiency, conservation and sustainability policies should focus on the development of technologies that reduce the content of hazardous and rare metals in lighting products without compromising their performance and useful lifespan.
Accomplishing simple, solubility-based separations of rare earth elements with complexes bearing size-sensitive molecular apertures
- Proceedings of the National Academy of Sciences of the United States of America
- Published about 3 years ago
Rare earth (RE) metals are critical components of electronic materials and permanent magnets. Recycling of consumer materials is a promising new source of rare REs. To incentivize recycling, there is a clear need for the development of simple methods for targeted separations of mixtures of RE metal salts. Metal complexes of a tripodal hydroxylaminato ligand, TriNOx(3-), featured a size-sensitive aperture formed of its three η(2)-(N,O) ligand arms. Exposure of cations in the aperture induced a self-associative equilibrium comprising RE(TriNOx)THF and [RE(TriNOx)]2 species. Differences in the equilibrium constants Kdimer for early and late metals enabled simple separations through leaching. Separations were performed on RE1/RE2 mixtures, where RE1 = La-Sm and RE2 = Gd-Lu, with emphasis on Eu/Y separations for potential applications in the recycling of phosphor waste from compact fluorescent light bulbs. Using the leaching method, separations factors approaching 2,000 were obtained for early-late RE combinations. Following solvent optimization, >95% pure samples of Eu were obtained with a 67% recovery for the technologically relevant Eu/Y separation.
Known stable [Cr(bpy)2(Ph)2](BPh4) complexes undergo reductive elimination of biphenyl with visible-light photolysis using household incandescent or compact fluorescent light bulbs. A series of [Cr(R-bpy)2(Ar)2](X) complexes (R = H or CMe3; Ar = Ph, C6H4-CMe3, or C6H4-OMe; X = I, BPh4, or PF6) were prepared, and the effect of varying the bipyridine and aryl ligands on the UV-visible spectra and electrochemistry of the chromium(III) complexes was investigated. Photolysis of a mixture of two different bis(aryl) complexes gave only the homocoupled biaryl products by1H NMR and gas chromatography/mass spectrometry analysis. The initial product of photoinduced reductive elimination of [Cr(bpy)2(Ar)2](PF6) was trapped with bipyridine to generate [Cr(bpy)3](PF6) and with benzoyl peroxide to form [Cr(bpy)2(O2CPh)2](PF6). The latter chromium(III) bis(benzoate) complex was also synthesized by the addition of bipyridine and PhCO2H to Cp2Cr, followed by air oxidation. The neutral Cr(bpy)(S2CNMe2)Ph2complex also generated biphenyl upon visible-light photolysis. While the treatment of Cr(tBu-bpy)(dpm)Cl2[dpm = (OCtBu)2CH] with AgO2CPh gave trans-Cr(tBu-bpy)(dpm)(O2CPh)2, reaction of the dichloro precursor with PhMgCl produced anionic [Cr(tBu-bpy)Ph3]-with [Mg(dpm)(THF)4]+as the countercation, with both complexes characterized by single-crystal X-ray diffraction. Protonolysis of Cr(bpy)Ph3(THF) with 8-hydroxyquinoline produced Cr(bpy)(quin)Ph2, which generated biphenyl under visible-light photolysis, and the initial product of reductive elimination was trapped by bipyridine or benzoyl peroxide. A related Cr(bpy)(quin)2complex was synthesized by protonolysis of Cr(bpy)[N(SiMe3)2]2and characterized by single-crystal X-ray diffraction.
The plethora of design opportunities renders organic light emitting diodes (OLEDs) ideal luminaires for general lighting applications. Progressing from lab-scale device concepts to large-area applications calls for smart device designs that are scalable and, at the same time, unsusceptible to resistive losses within the electrodes. By employing direct pulsed femtosecond laser structuring, we fabricate OLED luminaires comprising monolithically interconnected OLED arrays. We determine the laser ablation thresholds and the optimized process parameters for all functional layers. The clean laser cuts with precise ablation depths show about no damage to adjacent layers or any ridges, hence avoiding unwanted short-cuts or device isolation. All processes are scalable. The threefold structuring of the OLED luminaire is confined within 45 µm, yielding a geometric fill factor beyond 99 % and hence a very homogenous device perception.
In this report, we showed the existence of RET induced intermolecular pairing force by comparing their fluorescence behaviors under room illumination vs standing in dark area for either PFluAnt solution or PFluAnt&PFOBT mixture. Their prominent emission attenuation under room illumination brought out the critical role of photo, i.e. RET induced intermolecular pairing force in induction of polymer aggregation. Constant UV-Vis absorption and fluorescence spectra in terms of both peak shapes and maximum wavelengths implied no chemical decomposition was involved. Recoverable fluorescence intensity, fluorescence lifetime as well as NMR spectra further exclude photo induced decomposition. The controllable on/off state of RET induced intermolecular pairing force was verified by the masking effect of outside PFluAnt solution which function as filter to block the excitation of inside PFluAnt and thus off the RET induced intermolecular pairing force. Theoretical calculation suggest that magnitude of RET induced intermolecular pairing force is on the same scale as that of van der Waals interaction. Although the absolute magnitude of RET induced intermolecular pairing force was not tunable, its effect can be magnified by intentionally turn it “on”, which was achieved by irradiance with 5 W desk lamp in this report.
To describe a simple technique that uses posterior chandelier illumination during Descemet membrane endothelial keratoplasty in cases of severe bullous keratopathy (BK).
Based on available literature, ecology and economy of LED (light emitting diode) lights in plant foods production were assessed and compared to HPS (high pressure sodium) and CFL (compact fluorescent light) lamps. The assessment summarises that LEDs are superior compared to other lamp types. LEDs are ideal in luminous efficiency, life span and electricity usage. Mercury, carbon dioxide and heat emissions are also lowest in comparison to HPS and CFL lamps. This indicates that LEDs are indeed economic and eco-friendly lighting devices. The present review indicates also that LEDs have many practical benefits compared to other lamp types. In addition, they are applicable in many purposes in plant foods production. The main focus of the review is the targeted use of LEDs in order to enrich phytochemicals in plants. This is an expedient to massive improvement in production efficiency, since it diminishes the number of plants per phytochemical unit. Consequently, any other production costs (e.g., growing space, water, nutrient and transport) may be reduced markedly. Finally, twenty four research articles published in 2013-2017 were reviewed for targeted use of LEDs in the specific, i.e. blue range (400-500 nm) of spectrum. The articles indicate that blue light is efficient in enhancing the accumulation of health beneficial phytochemicals in various species. The finding is important from the global food production.
A candlelight-style organic light emitting diode (OLED) is a human-friendly type of lighting because it is blue-hazard-free and has a low correlated color temperature (CCT) illumination. The low CCT lighting is deprived of high-energy blue radiation, and it can be used for a longer duration before causing retinal damage. This work presents the comprehensive protocols for the fabrication of blue-hazard-free candlelight OLEDs. The emission spectrum of the OLED was characterized by the maximum exposure time limit of the retina and the melatonin suppression sensitivity. The devices can be fabricated using dry and wet processes. The dry-processed OLED resulted in a CCT of 1,940 K and exhibited a maximum retinal exposure limit of 1,287 s at a brightness of 500 lx. It showed 2.61% melatonin suppression sensitivity relative to 480 nm blue light. The wet-processed OLED, where the spin coating is used to deposit hole injection, hole transport, and emissive layers, making fabrication fast and economical, produced a CCT of 1,922 K and showed a maximum retinal exposure limit of 7,092 at a brightness of 500 lx. The achieved relative melatonin suppression sensitivity of 1.05% is 86% and 96% less than that of the light emitting diode (LED) and compact fluorescent lamp (CFL), respectively. Wet-processed blue-hazard-free candlelight OLED exhibited a power efficiency of 30 lm/W, which is 2 times that of the incandescent bulb and 300 times that of the candle.
A new protocol for photochemical perfluoroalkylation reactions using perfluoroalkyl iodide, amine additive, and THF solvent is reported. This protocol does not require a photoredox catalyst and proceeds at ambient temperature with irradiation from a compact fluorescent lamp, low-intensity UV lamp, or sunlight. This protocol can be applied to the synthesis of perfluoroalkyl-substituted phenanthridines as well as effect the iodo-perfluoroalkylation of alkenes/alkynes and the C-H perfluoroalkylation of electron-rich arenes and heteroarenes. This C-H perfluoroalkylation reaction offers a unique method for site-selective labeling of oligopeptides at the tryptophan residue.