Erratum to: Multifunctional peptide conjugated amphiphilic cationic copolymer for enhancing ECs targeting,penetrating and nuclear accumulation

The authors regret that there was an error in our publication.Considering Lingchuang Bai made great contributions to this work,Xinghong Duo and Lingchuang Bai should be co-first authors,but there was no statement that“Xinghong Duo and Lingchuang Bai contributed equally to this work”.The authors would like to apologize for any inconvenience caused.     

Toward Low-Cost,High-Energy Density,and High-Power Density Lithium-Ion Batteries

Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by ~70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.     

Serum concentrations of neutral and phenolic organohalogens in pregnant women and some of their infants in The Netherlands

As part of a large European Union (EU)-funded comparative toxicology and human epidemiology study, EU-Compare, a selection of organohalogen compounds (OHCs) was analyzed in maternal serum, collected at the 35th week of pregnancy, and in cord serum of a number of their infants to determine maternal concentrations and to investigate the extent of transplacental transfer of these compounds. Eight neutral OHCs were analyzed: one polychlorinated biphenyl (PCB: CB-153),4,4'-DDE, five polybrominated diphenyl ethers (PBDEs: BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154), and hexabromocyclododecane (HBCDD). Five phenolic OHCs were analyzed: three hydroxylated PCBs (40H-CB-107, 40H-CB-146, and 40H-CB-187), one hydroxylated PBDE (60H-BDE-47), and pentachlorophenol (PCP). All OHCs, except 60H-BDE-47, were present in maternal and cord serum. The historically identified OHCs showed the highest concentration: 4,4'-DDE (median value 89 ng/g lipid in maternal serum and 68 ng/g lipid in cord serum) and PCP (median value 970 pg/g serum in maternal serum and 1500 pg/g serum in cord serum). HBCDD and the PBDEs were present at much lower concentrations. We conclude that OHCs are present in the serum of pregnant women, and all compounds tested are transferred over the placenta. Because transfer is occurring at a critical stage of infant development, investigation of the health impact is urgent.     

Polysaccharide production by kefir grains during whey fermentation

Fermentation of deproteinised whey with kefir grains CIDCA AGK1 was studied focusing on polysaccharide production from lactose. Kefir grains were able to acidify whey at different rates depending on the grain/whey ratio. During fermentation, kefir grains increased their weight and a water-soluble polysaccharide was released to the media. Exopolysaccharide concentration increased with fermentation time, reaching values of 57.2 and 103.4 mg/l after 5 days of fermentation in cultures with 10 and 100 g kefir grains/l, respectively. The polysaccharide fraction quantified after fermentation corresponded to the soluble fraction, because part of the polysaccharide became a component of the grain. Weight of kefir grains varied depending on the time of fermentation. Polysaccharide production was affected by temperature. Although the highest concentration of polysaccharide in the media was observed at 43 degrees C at both grain/whey ratios, the weight of the grains decreased in these conditions. In conclusion, kefir grains were able to acidify deproteinised whey, reducing lactose concentration, increasing their weight and producing a soluble polysaccharide.     

Status and Potential of Spate Irrigation in Ethiopia

This article discusses spate irrigation in Ethiopia and aims to take stock of the current status of spate irrigation development. It summarizes experiences so far and formulates a number of recommendations on the development of this upcoming resource management system. It argues that raised weirs are useful mainly in areas where a large head for spate flow diversion is required, but that traditional earthen structures with conical stone/gabion reinforcements are cost-effective and technically adequate for floodwater distribution and management. It contends that the practical successes of sediment settling ponds (gravel traps) are at best mixed. Even where a small basin is justified, it can only ever trap a small proportion of the incoming sediment load. It is better to allow large floods with excessive sediment load (>100,000 ppm) to by-pass upstream intakes to be diverted lower down the system, and provide additional livelihood opportunities in downstream areas in the form of rangeland and agro-forestry development. This is particularly useful in the lowlands of Ethiopia with large pastoral community where spate irrigation is yet to make in-roads. The article further explains that water rights in spate are different from the sharing and allocation of perennial flows—they are dynamic and respond to a situation that differs from year to year as well as within a year and that a certain degree of inequity among users is inevitable. Keeping the command area compact can ensure two or more irrigation turns and this can highly increase productivity as crops are no longer in the ‘stress zone’. To transform spate irrigation in Ethiopia from subsistence to a business-oriented production system, the article proposes the promotion of cash crops including pulses and oil seeds as well as encouraging investors to go for bio-fuel development and agro-forestry in the lowland areas where huge potential exist. To avoid vehement conflicts that may arise among the settled agricultural and pastoral communities due to the implementation of the business-oriented production system, the traditional rights of the pastoral communities must be respected and their rangeland and water resources be safeguarded. For maximum yield, soil moisture conservation measures such as pre-irrigation land preparation, deep ploughing and mulching are essential as is the conjunctive use of spate flow and groundwater. Last, but most important, the article emphasizes that farmers need to be placed at the heart of any spate irrigation development programme as primary beneficiaries, managers and operators as well as part of the decision making institution.     

A numerical study of vortex interactions with flames developing from ignition kernels in lean methane/air mixtures

In this work, the outcomes of interactions of counter-rotating vortex pairs with developing ignition kernels are studied. The conditions are selected to represent those in a lean-burn natural-gas engine with hot-jet ignition. The evolution of flame surface area during kernel–vortex interaction is quantitatively and qualitatively examined. It is observed that flame development is accelerated and the net flame surface area growth rate, i.e. heat release rate, increased with increasing vortex velocity. In general, increasing the vortex length scale increases the surface growth rate, i.e. increases heat release rates, but for small length scales, i.e. when the ratio of vortex length scale to kernel diameter is small, high flame curvature induced during the interaction leads to flame weakening and slower growth rates. When the vortex velocity is high relative to the flame speed and the length scale is comparable to the kernel diameter, the vortex breaks through the ignition kernel carrying with it hot products of combustion. This accelerates growth of the flame surface area and heat release rates compared to a kernel with no vortex interaction. On decreasing the vortex velocity and increasing the length scale, the wrinkling of the kernel becomes important. This also results in increased surface growth rates and higher heat release rates.     

XRD study of the grain growth in CdTe films annealed at different temperatures

The CdTe thin films electrodeposited on stainless steel substrates were annealed in air at various temperatures and time durations in order to investigate the influence of post-deposition heat treatments on the grain growth of the films. The recrystallization process at lower annealing temperature is different from that of the high-temperature annealing. The annealing at lower temperature promotes better grain growth by maintaining the preference for the (1 1 1) plane. In general the grain size increases due to annealing and the recrystallization happens in three phases. The grain growth exponent is a function of temperature and time. In the beginning of the annealing, irrespective of the annealing temperatures the grain growth obeys the ideal parabolic law and for longer annealing times it deviates from the ideal case.     

Design and optimization of a single stage centrifugal compressor for a solar dish-Brayton system

According to the requirements of a solar dish-Brayton system,a centrifugal compressor stage with a minimum total pressure ratio of 5,an adiabatic efficiency above 75% and a surge margin more than 12% needs to be designed.A single stage,which consists of impeller,radial vaned diffuser,90° crossover and two rows of axial stators,was chosen to satisfy this system.To achieve the stage performance,an impeller with a 6:1 total pressure ratio and an adiabatic efficiency of 90% was designed and its preliminary geometry came from an in-house one-dimensional program.Radial vaned diffuser was applied downstream of the impeller.Two rows of axial stators after 90° crossover were added to guide the flow into axial direction.Since jet-wake flow,shockwave and boundary layer separation coexisted in the impeller-diffuser region,optimization on the radius ratio of radial diffuser vane inlet to impeller exit,diffuser vane inlet blade angle and number of diffuser vanes was carried out at design point.Finally,an optimized centrifugal compressor stage fulfilled the high expectations and presented proper performance.Numerical simulation showed that at design point the stage adiabatic efficiency was 79.93% and the total pressure ratio was 5.6.The surge margin was 15%.The performance map including 80%,90% and 100% design speed was also presented.     

The Design of Cold Plates for the Thermal Management of Electronic Equipment

Cold plates, devices used for the thermal management of electronic equipment, consist of a fluid flow space that is bounded by metallic walls. The fluid passages are designed to optimize the heat extraction from the electronics. This paper deals with the fluid flow and heat transfer in cold plates in which both the fluid flow and heat transfer experience periodic variations in the streamwise direction. The motivation for the work was to devise a methodology for dealing with problems that are highly complex and also computationally demanding. The first goal of the work was to transform the combined problems of fluid flow and conjugate heat transfer into one in which the wall heat transfer can be solved separately. The decoupling was achieved by first focusing on the solution of the full conjugate heat transfer problem for a portion of the periodic array. From this solution, heat transfer coefficients were extracted and subsequently employed for the solution of the wall heat conduction problem for the entire cold plate. The second focus was the development of enhancements of the heat transfer performance of cold plates. Consideration was given to manufacturing as well as thermal and fluid flow issues.