Higher Specific Yield Research Articles

Performance of vertically mounted bifacial photovoltaics under the physical influence of low-rise residential environment in high-latitude locations

This study focuses on finding suitable installation sites for vertical bifacial photovoltaic (VBPV) panels in urban low-rise neighborhoods at high latitudes. The power production of east-west-oriented VBPV systems matches well with domestic electricity consumption profiles, increasing the self-consumption of PV electricity. Furthermore, PV electricity adds economic value by avoiding transmission fees and taxes. These systems are especially beneficial in high-latitude locations characterized by a low solar elevation angle. However, these low angles expose VBPV panels to a high risk of shading losses from their surroundings, and it is unknown how much shading limits the number of suitable installation sites. Here, environmental shading on VBPV panels is quantified for three low-rise residential neighborhoods in Helsinki, a high-latitude location, by comparing the specific yields (annual electricity production per kilowatt peak) of VBPV and monofacial PV (MPV) systems. The results showed that unshaded VBPV systems have a higher specific yield than their MPV counterparts. However, in densely built neighborhoods with tall trees, the lack of suitable installation sites for VBPV panels severely limits the peak power of these systems. Roof ridge VBPVs usually yield high production, while façade- and ground-mounted systems lose between 30% and 70% compared to roof ridge VBPV systems depending on their installation locations. South-oriented MPVs perform better than VBPVs on north-south-facing roofs, both in terms of specific yield and total annual production. Conversely, VBPVs installed on the ridges of unshaded roofs aligned closely with the north-south axis outperform MPVs on east- and west-facing roofs by 20%–30%.

Spatial modeling of indicators for groundwater use in Brazil

This study spatially characterizes the potential and pressure of the supply of groundwater resources in Brazil. Indicators obtained from ordinary kriging, kernel density estimation, and multivariate geovisualization techniques using the Brazilian Groundwater Information System (SIAGAS) were proposed. The cartographic results culminated in maps of the potential and pressure of groundwater use in Brazil and proved to be promising for the planning and management of water resources. Sedimentary basins had the highest specific yield (2.16 m3/h*m) and stabilization yield (11.19 m3/h), as well as the greatest total abstraction pressure (1054967 m3/h), although they had lower exploitation by aquifer area (0.54 m3/h*km2) than carbonate (1.91 m3/h*km2) and volcanic aquifers (0.80 m3/h*km2). Contrastingly, crystalline aquifers had the lowest specific yield (0.63 m3/h*m), and stabilization yield (5.71 m3/h). Specifically, it highlights the potential use of the Alter do Chão aquifer in northern Brazil and the western Guarani and Bauru-Caú aquifers, while they indicate a concern with the pressure of use on these last two aquifers, as well as on the Urucuia aquifer and on the metropolitan regions, especially of São Paulo.

Experimental comparison between Monocrystalline, Polycrystalline, and Thin-film solar systems under sunny climatic conditions

Solar photovoltaic (PV) is the fastest growing renewable energy technology in terms of installed capacity worldwide. Since there are different PV technologies available, a reliable long-term evaluation of these technologies under actual operation conditions would be very helpful and valuable for further development and deployment of this technology. This study presents the performance indicators for about six years of operation for a solar field that consists of five different solar systems (around 5 kW each), these systems are Monocrystalline East/West, Monocrystalline South, Polycrystalline South, Polycrystalline East/West, and Thin-film system oriented toward the south. These systems are installed at the Applied Science Private University (ASU), Amman, Jordan. The key performance indicators investigated are the performance ratio (PR), specific yield, and system efficiency (EFF). The highest efficiency was achieved by the Mono South system, and the lowest efficiency of 7% was recorded for the thin film south system. Similarly, the highest performance ratio was obtained by the Mono south system, while the lowest was for the Poly E/W system. The highest specific yield with respect to the installed capacity (kWh/kWp) was achieved by the Thin-film south system, while the lowest was obtained by the Poly south system. These results are supposed to guide not only solar PV project developers but also policymakers in the selection and implementation of suitable PV technology for a given region.

Comparison of highly pure rAAV9 vector stocks produced in suspension by PEI transfection or HSV infection reveals striking quantitative and qualitative differences

Recent clinical successes have propelled recombinant adeno-associated virus vectors (rAAV) to the center stage for human gene therapy applications. However, the exploding demand for high titers of highly pure rAAV vectors for clinical applications and market needs remains hindered by challenges met at the manufacturing stage. The production of rAAV by transfection in suspension cells remains one of the most commonly used production platforms. In this study, we describe our optimized protocol to produce rAAV by polyethyleneimine (PEI)-mediated transfection in suspension HEK293 cells, along with a side-by-side comparison to our high-performing system using the herpes simplex virus (HSV). Further, we detail a new, robust, and highly efficient downstream purification protocol compatible with both transfection and infection-based harvests that generated rAAV9 stocks of high purity. Our in-depth comparison revealed quantitative, qualitative, and biological differences between PEI-mediated transfection and HSV infection. The HSV production system yielded to higher rAAV vector titers, higher specific yields, and a higher percentage of full capsids than transfection. Furthermore, HSV-produced stocks had a significantly lower concentration of residual host cell proteins and helper DNA impurities, but contained detectable levels of HSV DNA. Importantly, the potency of PEI-produced and HSV-produced rAAV stocks were identical. Analyses of AAV Rep and Cap expression levels and replication showed that HSV-mediated production led to a lower expression of Rep and Cap, but increased levels of AAV genome replication. Our methodology enables high-yield, high purity rAAV production and a biological framework to improve transfection quality and yields by mimicking HSV-induced biological outcomes.

Development from Alloys to Nanocomposite for an Enhanced Mechanical and Ignition Response in Magnesium

The current study reports on the evolution of microstructure, variations in compressive properties and the ignition resistance of Mg through compositional variation, using alloying elements and nanoreinforcement. The alloys were designed with the use of a singular alloying element, Ca, and a binary alloying element, Ca+Sc, to develop Mg1Ca (wt.%) and Mg1Ca1Sc (wt.%) alloys. B4C nanoparticles were addedas the reinforcement phase in the Mg1Ca1Sc alloy to create the Mg1Ca1Sc/1.5B4C (wt.%) nanocomposite. The most effective compressive properties and level of ignition resistance was displayed by the developed composite. The grain sizes were significantly reduced in the Mg alloys (81%) and the composite (92%), compared with that of the Mg. Overall, the microstructural features (i.e., grain refinement, the formation of favorable intermetallic compounds, and hard reinforcement particles with an adequate distribution pattern) enhanced both the compressive strength and strain of the alloys and the composite. The ignition resistance was progressively increased from the alloys to the nanocomposite, and a peak ignition temperature of 752 °C was achieved in the composite. When compared with the ignition resistant of Elektron 21 (E21) alloy, which met the Federal Aviation Administration (FAA) requirements, the Mg1Ca1Sc/1.5B4C nanocomposite showed a higher specific yield strength and better ignition resistance, asserting it as a potential candidate material for lightweight engineering applications, including aerospace and defense sectors.

Long-term rewetting of degraded peatlands restores hydrological buffer function

Precipitation is a key factor affecting shallow water table fluctuations. Although the literature on shallow aquifers is vast, groundwater response to precipitation in peatlands has received little attention so far. Characterizing groundwater response to precipitation events in differently managed peatlands can give insight into ecohydrological processes. In this study we determined the groundwater table response rate following precipitation events at a drained and a rewetted fen to characterize the effect of rewetting on hydrological buffer capacity. Multiple regression analysis revealed that the groundwater table at the rewetted fen has more than two times lower rate of response to precipitation events than that of the drained fen, even after adjusting for antecedent groundwater levels. Thus, the rewetted fen delivers a better hydrological buffer function against heavy precipitation events than the drained fen. We found that for the depths at which the groundwater interacts with incoming precipitation, the peat of the rewetted fen has a higher specific yield causing groundwater to rise slower compared to the response at the drained fen. A period of 20 years of rewetting was sufficient to form a new layer of organic material with a significant fraction of macropores providing storage capacity. Long-term rewetting has the potential to create favorable conditions for new peat accumulation, thereby altering water table response. Our study has implications for evaluating the success of restoration measures with respect to hydrological functions of percolation fens.

ИССЛЕДОВАНИЕ ИНТЕНСИВНОСТИ КОНВЕКТИВНОЙ ПЕНОСУШКИ ЖЕЛАТИНОВОГО БУЛЬОНА ИЗ ОТХОДОВ ПЕРЕРАБОТКИ РЫБ ЧАСТИКОВЫХ ПОРОД

The intensity of the process of convective foam drying of gelatinized broth prepared from ordinary fish waste in the Astrakhan region was studied experimentally. The product was dried in a foamed state in a layer with a unilateral convective energy supply, as well as in the foamed and natural state in the form of round bars with a uniform convective energy supply. The ranges of variation of the main factors influencing the process were selected and substantiated, and their effect on the objective function (yield of dry gelatin per unit time per unit area) was analyzed. Approximating dependencies of the objective function on the main factors are obtained. According to the results of the research, application of a uniform convective energy supply in the course of drying gelatin broth under rational regimes allows to increase specific productivity of the process by 1.5 times, compared to drying with a unilateral energy supply, and to shorten the drying time from 4.2 to 2.3 hours. In this case, foaming the product results in more than a twofold increase in productivity while reducing the drying time by almost twice. The rational regimes for carrying out the process of convective drying of gelatinized broth in producing dry gelatin are determined: convective drying of the gelatinized broth should be conducted in a foamed state, with a uniform power supply, in the form of bars with circular cross section under the following conditions: initial diameter dn of a round bar = 0.004 m, initial moisture wn of product = 75%, flow rate v of the drying agent not less than 4.5 m/s, temperature T of the drying agent = 293-295 K. The indicated regimes provide the highest specific yield of the dry product G = 0.33 kg/(m2·h) and are recommended for practical use in order to increase the intensity of the process while maintaining the quality of dry gelatin.

Microbial community composition and diversity in rice straw digestion bioreactors with and without dairy manure

Anaerobic digestion (AD) uses a range of substrates to generate biogas, including energy crops such as globally abundant rice straw (RS). Unfortunately, RS is high in lignocellulosic material and has high to C:N ratios (~80:1), which makes it (alone) a comparatively poor substrate for AD. Co-digestion with dairy manure (DM) has been promoted as a method for balancing C:N ratios to improve RS AD whilst also treating another farm waste and co-producing a potentially useful fertiliser. However, past co-digestion studies have not directly compared RS AD microbial communities with and without DM additions, which has made it hard to assess all impacts of DM addition to RS AD processes. Here, four RS:DM ratios were contrasted in identical semi-continuous-fed AD bioreactors, and 100% RS was found to produce the highest specific methane yields (112 mL CH4/g VS/day; VS, volatile solids), which is over double yields achieved in the reactor with the highest DM content (30:70 RS:DM by mass; 48 mL CH4/g VS/day). To underpin these data, microbial communities were sequenced and characterised across the four reactors. Dominant operational taxonomic units (OTUs) in the 100% RS unit were Bacteroidetes/Firmicutes, whereas the 30:70 RS:DM unit was dominated by Proteobacteria/Spirochaetes, suggesting major microbial community shifts occur with DM additions. However, community richness was lowest with 100% RS (despite higher specific yields), suggesting particular OTUs may be more important to yields than microbial diversity. Further, ambient VFA and VS levels were significantly higher when no DM was added, suggesting DM-amended reactors may cope better with higher organic loading rates (OLR). Results show that RS AD without DM addition is feasible, although co-digestion with DM will probably allow higher OLRs, resulting in great RS throughput in farm AD units.

Inferring hydraulic properties of alpine aquifers from the propagation of diurnal snowmelt signals

AbstractAlpine watersheds source major rivers throughout the world and supply essential water for irrigation, human consumption, and hydroelectricity. Coarse depositional units in alpine watersheds can store and transmit significant volumes of groundwater and thus augment stream discharge during the dry season. These environments are typically data scarce, which has limited the application of physically based models to investigate hydrologic sensitivity to environmental change. This study focuses on a coarse alpine talus unit within the Lake O'Hara watershed in the Canadian Rockies. We investigate processes controlling the hydrologic functioning of the talus unit using field observations and a numerical groundwater flow model driven with a distributed snowmelt model. The model hydraulic parameters are adjusted to investigate how these properties influence the propagation of snowmelt‐induced diurnal signals. The model results expectedly demonstrate that diurnal signals at the talus outlet are progressively damped and lagged with lower hydraulic conductivity and higher specific yield. The simulations further indicate that the lag can be primarily controlled by a higher hydraulic conductivity upper layer, whereas the damping can be strongly influenced by a lower hydraulic conductivity layer along the base of the talus. The simulations specifically suggest that the talus slope can be represented as a two layer system with a high conductivity zone (0.02 m s−1) overlying a 10 cm thick lower conductivity zone (0.002 m s−1). This study demonstrates that diurnal signals can be used to elucidate the hydrologic functioning and hydraulic properties of shallow aquifers and thus aid in the parameterization of hydrological models.

Effect of Fe load on the synthesis of C nanotubes by isobutane decomposition over Na-exchanged montmorillonite-clay catalysts

This work is a continuation and a completion of a previous study on the synthesis of multi-walled carbon nanotubes by iron-catalyzed chemical vapor deposition over sodium-exchanged K10-montmorillonite (Na+-K10) based catalysts. The influence of iron-addition (5–25wt.%) on the catalyst performances is investigated. By comparing results here obtained by isobutane decomposition at 700°C with those previously achieved at 600°C by using Fe/Al2O3 catalysts upon the same gas-flowing setup (120cm3/min 1:1 i-C4H10+H2), it comes out that although in both the cases the best catalytic performance is obtained for a relative (to iron) carbon-supply of≈160wt.%/min, higher specific yield is achieved over alumina supported catalysts. The possible reasons for this difference are discussed in the light of the most recent assessments on nanotube growth.

Modelling the hydrogeology and managed aquifer system of the Chalk across southern England

Abstract Six regional recharge and groundwater models have been recently developed of the Chalk and Upper Greensand from Dorset to Kent. Updated Chalk stratigraphy and mapping have improved understanding of geological structure and the development of preferential groundwater flow pathways along hardground horizons. Where shallow dipping folds bring these into the zone of active groundwater flow, extensive ‘underdrainage’ may result in marked differences between surface and groundwater catchments. Hardgrounds and marls are also associated with spring discharges, as are some faults and the clay formations that underlie or confine the aquifer system. Higher specific yield within the Upper Greensand helps support summer baseflow, as do local groundwater discharges from augmentation schemes, watercress and fish farm operations. The aquifer system has been successfully modelled using the ‘variable hydraulic conductivity with depth’ version of MODFLOW. Depths of secondary permeability development have been distributed according to ground and groundwater level data. Interfluve–valley contrasts overlie a base hydraulic conductivity set according to the formation saturated at the water table and enhanced by active hardgrounds. Local parameter overrides may also be needed. The Wessex Basin conceptual and numerical model is described before summarizing similarities and contrasts from the other five regional model areas.

Tree vigour, cropping, and phenology of sweet cherries in two systems of tree training on dwarf rootstocks

Five cultivars and four rootstocks (Gisela 5, P-HL-A, P-HL-B, and Tabel Edabriz) were evaluated on trees in fruiting stage trained like spindle and on trellis. Tree vigour was significantly related to cultivar, rootstock and to tree training. Spindles were generally more vigorous than trees on trellis with exception of cv. Kordia. In several cases special combinations of cultivar, rootstock, and method of tree training differed significantly from mean effects of the three factors. Time of flowering was significantly dependent on the cultivar and varied annually within 15 days. Time of fruit harvest was also influenced by the rootstock and in two cases mutually contradictory to the tree training method. Yields per tree were generally dependent on the cultivar. With Burlat and cv. Kordia rootstock and tree training were also important. Higher specific yields were recorded on trellis-trained trees. Remarkable in this respect were Vanda and trees of Summit on P-HL-B and Starking Hardy Giant on Tabel Edabriz. Higher specific yields on spindle had Kordia on P-HL-A and Tabel Edabriz and Burlat on P-HL-A. Mean values of annual yields per hectare in spindle ranged between 10.0 to 17.5 t whereas in trellis between 6.7 to 12.3 t. The absolute highest annual yield (35.7 t) was recorded on spindle trees of Kordia on P-HL-A. In trellis the highest yield of 27.1 t had Kordia on Gisela 5. The advantage of spindle over trellis was greater in Burlat and Kordia but much lower in cv. Vanda. Fruit size mainly depended on the year. Only two rootstocks influenced fruit size differently in some years. Training system had no effect on fruit size.

Impact of plasmid induction strategy on overall plasmid DNA yield and E. coli physiology using flow cytometry and real-time PCR

DNA-based vaccines and gene therapies have rapidly evolved since the first demonstration of in vivo gene expression by naked DNA injection. When optimizing their production, the major goals in the fermentation process are to maximize the specific plasmid yield, as well as plasmid quality, while minimizing plasmid-mediated metabolic burden. Due to this fact, the development of new and fast monitoring techniques able to easily assess plasmid-mediated metabolic burden and process productivity is in demand. In this work, Escherichia coli DH5 alpha harboring plasmid pVAX1- LacZ was grown in semi-defined media using several pDNA induction strategies. The effect of the induction strategy on cell physiology and overall process productivity was monitored using multi-parameter flow cytometry and real-time qPCR. All induction strategies caused cell filamentation and decreased viability at the end of fermentation. The results also suggest that an amino acid limitation with AMP addition induction strategy resulted in the highest specific yields (20.94 mg/g) and, concomitantly, highest plasmid copy number (1070 per cell). In conclusion, amino acid limitation with AMP addition seems to be a suitable approach to be implemented at a large scale level since it does not require any additional energy and it has proved to be efficient in plasmid amplification.

Techno-economic Analysis of Electricity Generation by Means of a Proposed 50 MW Grid-connected Wind Power Plant for Jordan

Complying with the decision made by the Jordanian government to install a new wind power plant with a capacity ranging between 50–75 MW—to complement the Hofa and Ibrahimiyya wind power plants, whose electricity production presently forms only about 0.035% of the total electricity generated in Jordan mainly by power plants operating on conventional fuels—a 50 MW grid-connected wind power plant for electricity generation is proposed. Long-term (1993–2004) measured wind speed data at 24 widespread Jordanian sites was analyzed, and formed—in addition to the plant's specifications and parameters—an input data to carry out evaluation of the proposed plant's electricity production and analysis of its economic feasibility. It was found that the mean annual value of wind speed for Jordan is 5.5 m/s and that the seasonal trend of wind speed—for most of the studied sites and Jordan as a whole—matches the electricity load trend in the country. It was also found that RasMuneef, among the studied sites, has the highest annual mean wind speed of 10.65 m/s, the highest electricity production of 260.9 GWh/year, the highest specific yield of 1,882 kWh/m2, and the best economic indicators, i.e., internal rate of return, simple payback period, years-to positive cash flow, net present value, annual life cycle saving, benefit-cost ratio, and cost of energy. Moreover, it was found that about 201,417 tons of greenhouse gas emissions can be avoided annually if utilizing the proposed plant for electricity generation at RasMuneef instead of plants operating on conventional fuels. Therefore, employing the proposed power plant for electricity generation, in Jordan in general and in RasMuneef in particular, is highly recommended.

Influence of Growth Conditions on Plasmid DNA Production

The obtention of high yields of purified plasmid DNA is viewed as an essential issue to be considered towards efficient production of DNA vaccines and therapeutic plasmids. In this work, Escherichia coli DH5alpha bearing the pVAX1-LacZ plasmid was grown in a developed semi-defined medium at different temperatures and tryptone concentrations. Analysis of pDNA yields and E. coli morphology revealed that at higher temperatures (37 and 40 degrees C), higher specific yields and E. coli filamentation were obtained. However, the best results were achieved when a lower tryptone concentration was used. This approach was shown to be a powerful tool to promote plasmid amplification, keeping the desirable plasmid structure, and favoring the attainment of quality. Our results suggest that by using tryptone alone as an amino acid source, pDNA amplification was improved and a specific yield of 20.43 mg pDNA/g dcw was achieved, proving that this strategy can improve pDNA yield even at a small scale.

Over-production of human interferon-γ by HCDC of recombinant Escherichia coli

A simple fed-batch process was developed using a modified variable specific growth rate feeding strategy for high cell density cultivation of Escherichia coli BL21 (DE3) expressing human interferon-gamma (hIFN-γ). The feeding rate was adjusted to achieve the maximum attainable specific growth rate during fed-batch cultivation. In this method, specific growth rate was changed from a maximum value of 0.55 h −1 at the beginning of feeding and then it was reduced to 0.4 h −1 at induction time. The final concentration of biomass and IFN-γ was reached to ∼115 g l −1 (DCW) and 42.5 g(hIFN-γ) l −1 after 16.5 h, also the final specific yield and overall productivity of recombinant hIFN-γ (rhIFN-γ) were obtained 0.37 g(hIFN-γ) g −1 DCW and 2.57 g(hIFN-γ) l −1 h −1, respectively. According to available data this is the highest specific yield and productivity that has been reported for recombinant proteins production yet.

Long-term oxidation of orthorhombic alloy Ti-22Al-25Nb in air between 650 and 800°C

Titanium alloys based on the orthorhombic phase Ti{sub 2}AlNb are currently under investigation for those aeroengine applications where the maximum service temperatures exceed the capabilities of conventional titanium alloys but are still lower than recommended for {gamma}-TiAl based aluminides. For some orthorhombic alloys, a better fracture toughness, higher ductility, higher specific yield and lower coefficient of thermal expansion for {gamma}-TiAl based alloys as well as for alpha-2 alloys has been reported and creep and fatigue behavior are similar to that of alpha-2 alloys. However, oxidation and embrittlement of orthorhombic alloys are a major concern when applications in the oxidizing atmosphere of an aeroengine and operating temperatures between 650 and 700 C are considered. The goal of the present study was to assess the long-term environmental resistance of high niobium-containing Ti-22Al-25Nb, an alloy presently under consideration for titanium matrix fiber reinforced composites (TMCs). TMCs are needed to introduce blisk (= bladed disk) and bling (= bladed ring) technology into modern aeroengine design. Oxidation tests on cast Ti-22Al-25Nb matrix material in laboratory air were conducted between 650 and 800 C up to 4,000 hr.

A New Tool: Delineation of Textural Heterogeneities in Unconfined Aquifers, Using Microgravity Surveys During Pumping

Hypothetical models of texturally heterogeneous aquifers indicate that microgravity surveys can be used to locate textural heterogeneities within the cone of depression caused by pumping in an unconfined aquifer. The difference in gravity between an undisturbed water table and a relatively steady drawdown cone is measured on profile lines. Small differences in gravity indicate zones of little dewatering which are typically areas where low hydraulic conductivity and/or low-specific yield materials occur near the water table. Large differences in gravity generally indicate more permeable and higher-specific yield materials. Magnitudes of the anomalies of interest are close to the detection limit. Therefore, it is essential that gravimeters used to conduct the survey are in excellent condition and that field personnel are well-trained. Because the survey delineates zones of fine-grained material in the vicinity of the water table, microgravity surveys may be useful in design of facilities to clean up spills of immiscible fluids that are less dense than water and are substantially influenced by the texture of alluvial deposits in the vicinity of the water table. Zones of fine-grained materials typically inhibit fluid movement and often are more chemically reactive with contaminants. As a result, identification of textural differences provides initial clues to both hydraulic and chemical heterogeneity.

Formation of Benzophenanthridine Alkaloids by Suspension Cultures of Eschscholtzia californica

Suspension cultures of Eschscholtzia californica accumulate the dihydro forms of the benzo- phenanthridine alkaloids sanguinarine, chelirubine, macarpine and chelerythrine, all of which are known to be constituents of the Eschscholtzia plant. Under most experimental conditions dihydrochelirubine was found to be the main constituent of the cultured cells. The specific yields of alkaloids varied from zero to 1.7% on a dry weight basis depending on the media conditions. The highest specific yield was 1.5 mg/g dry weight or 13 mg/1 with the growth medium B5. After transfer of the cells into the induction medium IM2 the alkaloid accumulation increased to 17 mg/g dry weight and 146 mg/1. The induction medium contained increased levels of sucrose, decreased levels of phosphate and was devoid of phytohormones. The effect of the various media conditions on the biosynthesis of phenolics was quite different to those found for the alkaloids.