Optimum manufacturing conditions of activated carbon fiber absorbents. II. Effect of carbonization and activation conditions

In this paper, viscose rayon-based knitted fabrics were utilized as the precursor to produce activated carbon fiber absorbents (ACFA). The effects of carbonization and activation conditions on characteristics (ACFA) were examined. Experimental results revealed that increasing the flow rate of environmental gas N₂ and steam activator used in conjunction and decreasing the production rate of ACFA can obtain better pore properties. However, higher flow rate of steam activator and lower production rate of ACFA reduced the weight yield. According to our findings, to maintain good absorption property of ACFA, the optimum manufacturing conditions are flow rate of gas N₂ at 80 cc/min, flow rate of steam activator at 60 ml/min, and production rate of ACFA at 30 cm/min, with flame retardant reagent concentration maintained at 30%. Under these conditions, the weight yield can be up to 40.85% and the BET surface area can exceed 1500 g/m².     

Genetic analyses of grain-filling rate and duration in maize

Grain-filling rate and duration influence grain yield in maize (Zea mays L.), but very little information on their inheritance exists. To devise effective breeding strategies, the genetic nature of these traits must be understood. The objectives of this study were to (1) examine general combining ability (GCA) and specific combining ability (SCA) for grain-filling rate, grain-filling duration, and related agronomic traits via North Carolina Design II, (2) determine the inter-relationships among these traits and their influence on yield via correlation and path coefficient analyses, and (3) identify an indirect selection criterion for yield. Design II crosses among four inbred lines used as males and a set of four inbred lines as female parents were grown in 1996. Combining ability analyses indicated that both GCA (V_g) and SCA mean squares (V_s) were significant for grain-filling rate (on a kernel or an ear basis) and effective filling duration. General combining ability was more important than SCA for both kernel-filling rate and effective filling duration, whereas SCA effect was more important for ear-filling rate. The ratio 2V_g/(2V_g + V_s) was 0.85, 0.88, and 0.45 for kernel-filling rate, effective filling duration, and ear-filling rate, respectively. Kernel-filling rate had a positive phenotypic correlation with kernel weight and was negatively correlated with midsilk date and effective filling duration. Kernel number per ear was more important than kernel-filling rate in influencing grain yield. These relationships were confirmed by results from a 1997 experiment using nine commercial hybrids. Chlorophyll readings taken with SPAD chlorophyll meter at a late developmental stage gave a positive genetic correlation with single-plant yield (r = 0.73). A path coefficient analysis revealed that chlorophyll concentration had a small direct effect on grain yield, whereas it had a large indirect effect on grain yield via kernel number per ear and grain-filling duration. Kernel weight and midsilk date could serve as indirect selection criteria for effective grain-filling duration and kernel-filling rate. Chlorophyll concentration at a late developmental stage could also be an indirect selection criterion for final grain yield.     

Effect of temperature and activators on the characteristics of activated carbon fibers prepared from viscose-rayon knitted fabrics

This study used viscose rayon-based knitted fabric, pre-treated by a composite flame retardant, as the precursor. The fabric then underwent oxidation, carbonization and activation in a semi-open high-temperature erect furnace to produce Activated Carbon Fabrics (ACF). The microstructure and chemical properties of the ACF were obtained under carbonization temperatures of 600–1000 °C and by different activation sources. The results showed that the ACF produced was mainly of a microporous structure. When the carbonization temperature was increased, the production rate dropped while both the true density (D_He) and crystallization thickness increased. In addition, ACF prepared using steam, plus water as the activation source, has a larger specific surface area, greater crystallization thickness and a higher true density (D_He).     

Retardation of shoot growth and promotion of tuber growth of potato plants by paclobutrazol

The relationship between shoot growth and tuber yield in potato plants (Solanum tuberosum L. cv. Russet Burbank) was studied under greenhouse conditions using paclobutrazol [(2R,3R + 2S,3S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(l,2-4-triazol-l-yl)-pentan-3-ol), PP333], a growth retardant. Concurrent with reduction of stem elongation by the application of paclobutrazol to base of the main stem was a decrease in the dry weight of the shoot and an increase in the dry weight of the tuber. The inhibitory effect of paclobutrazol on stem elongation was reversed by gibberellic acid A₃ (GA₃). Leaf content of raffinose sugar and chlorophyll increased upon paclobutrazol treatment.     

Floret development and spike growth as affected by photoperiod during stem elongation in wheat

A longer duration of stem elongation (from terminal spikelet initiation to anthesis) would result in a higher wheat yield potential as a consequence of the increase in both spike dry weight and number of fertile florets at anthesis. It is not clearly understood, however, which processes are involved in the increased spike dry weight and whether this variable accounts for the higher number of fertile florets when duration of stem elongation is modified by photoperiod treatments. As vernalization interacts with photoperiod during the stem elongation phase, a better understanding of the role of vernalization is also required. A field experiment was carried out using two wheat cultivars (Buck Manantial (BM) and Eureka Ferrocarril Sur (EFS)) subjected to diverse periods of vernalization (V₁₅ and V₅₀, plants vernalized for 15 and 50 days, respectively) and exposed to different photoperiods (NP+0 and NP+6, natural and 6 h extended photoperiod, respectively) only during the stem elongation phase. Floret development together with stem and spike growth during the stem elongation phase were studied. When the stem elongation phase was exposed to short photoperiod (i) duration of spike growth increased without any change in its growth rate, and (ii) most of the spike growth occurred during minimum stem growth rate as the onset of maximum stem growth rate was delayed. In EFS, the vernalization-sensitive cultivar, the former (i) and (ii) was true only when vernalization requirements were met. For both cultivars, the survival of the initiated floret primordia under short photoperiod increased, independently of vernalization. Both partitioning of assimilates to the spike and a direct photoperiod effect seemed to have been involved in the survival of floret primordia when the stem elongation phase was exposed to short photoperiod.     

Flame retardant properties of triazine phosphonates derivative with cotton fabric

The flame retardant behavior of cotton fabric treated with phosphorus-nitrogen containing triazine compound was evaluated. It was found that cyanuric chloride (2,4,6-trichloro-1,3,5-triazine) is an excellent starting material for the preparation of phosphonate flame retardants that interact well with cotton to improve flame resistance (FR) performance. Tetraethyl 6-chloro-1,3,5-triazine-2,4-diyldiphosphonate (TECTDP) has been prepared by a simple one-step reaction in high yield (98.0 %). Cotton fabrics treated with TECTDP result in covalent bond formation between TECTDP and hydroxyl groups in cotton fabrics. This FR system provides an efficient flame retardant for cotton textiles at low cost to meet government mandates. In this study, the FR material was synthesized and characterized by ¹H and ¹³C nuclear magnetic resonance (NMR), and LC-MS spectroscopy. The chemical structure of cotton twill fabric treated with TECTDP by pad-dry-cure method was analyzed by FT-MIR and SEM. Furthermore, the thermal and flammability properties were evaluated by thermogravimetric analysis (TGA), limiting oxygen index (LOI, ASTM D-2863-09), and a vertical flame test (ASTM D-6413-08).     

Correlation of Nitrogen Concentration with Dry-Matter Partitioning to Spikelets and Total Husk Volume on the Panicle in Japonica Rice

Summary

A rice husk restricts the grain development physically. We examined the correlation of the total husk volume on a panicle, a parameter of yield capacity, with the nitrogen concentration (per dry weight) and the dry weight of the above-ground part of the plant, using single-stem-trained japonica rice (cv. Nipponbare) plants. The growth of rice plants was regulated by shading at two levels and nitrogen application at three levels from about 40 days before the heading (about 10 days before the panicle initiation). The number of spikelets per dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage was linearly correlated with the nitrogen concentration at that time. The ratio of the spikelet dry weight at heading to the dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase of the ratio slowed down at a nitrogen concentration of 2%. Decrease in dry weight of the spikelet resulted in a decrease of lemma size. Therefore, the ratio of the total husk volume on a panicle to the plant dry weight at the end of spikelet differentiation stage also increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase stopped at a nitrogen concentration of 2% in contrast to the ratio of the spikelet number to the dry weight of the plant. These results suggest that, to increase the total husk volume on a panicle by nitrogen application, dry-matter production must be increased by the nitrogen application.     

Alkaline extraction and characterisation of heteroxylans from maize bran

Response surface methodology was used to study the alkaline extraction of heteroxylans from maize bran. The ratio volume of alkali/weight of bran and the particle size had no effect on extraction yield, whereas the yield increased significantly with the temperature and time of extraction and the concentration of the alkali. The variation in the yield depended on the nature of the alkali, and empirical second-order models were built to fit the results obtained by extraction with KOH and Ca(OH)₂. Comparison of the compositional and structural features of the heteroxylans obtained by extraction with 0·8 m KOH at 85 °C, saturated Ca(OH)₂ at 95 °C and 0·5 m KOH at 65 °C with one obtained by industrial lime-cooking of maize kernels showed that all four samples were very similar and that a very high extraction yield (87 %) was achieved.     

Evaluation of potential applications for chestnut (Castanea sativa) shell and eucalyptus (Eucalyptus globulus) bark extracts

The potential of chestnut shell and eucalyptus bark extracts as phenol substitutes in the formulation of adhesives, as chrome substitutes in leather tanning and as a source of antioxidants compounds has been studied. The influence of extraction conditions, type and concentration of alkaline compounds (NaOH, Na₂SO₃ and Na₂CO₃) and temperature, on extraction yield and on extract characteristics: Stiasny number, tannin content, total phenols content, FRAP (ferric reducing/antioxidant power) antioxidant capacity and molecular weight distribution was analysed. Chestnut shell extracts had much better properties than eucalyptus bark extracts and significantly higher extraction yields were obtained. The increase of temperature from 70 to 90 °C not only increased the extraction yield but also improved the quality of the extracts. For both materials, the 2.5% Na₂SO₃–90 °C extract, together with the 2.5% NaOH–2.5% Na₂SO₃–90 °C extract for chestnut shell, showed high extraction yields and the best properties for all the applications proposed.     

The effect of zinc ion content on flame retardance and thermal degradation of alginate fibers

The study employs limiting oxygen index (LOI) measurements, cone calorimetry (CONE) and thermogravimetric analysis (TGA) to examine the catalytic effect of zinc ion content on the flame retardance and thermal degradation of alginate fibers. LOI results show that all zinc alginate fibers are intrinsically flame retardant, with LOI values of over 27.0, as compared with about 24.5 for alginic acid fiber. The heat release rate (HRR) and total heat release values of zinc alginate fibers (obtained from CONE) are significantly less than those of alginic acid fiber, and decrease with increasing zinc ion content. TGA indicates that char formation increases and maximum thermal weight-loss rate is reduced when zinc content in the fibers is increased. The residues of zinc alginate fibers keep their shapes better than those of the alginic acid fiber. Further discussion of the combustion process and flame retardant mechanism is presented.     

Impact of selective flame weeding on onion yield,pungency, flavonoid concentration,and weeds

Field experiments were conducted to evaluate the effects of multiple selective flame weeding treatments on onion (Allium cepa L.). Onions were flamed between one and six times over the course of the season with a high (72 kg propane ha⁻¹) or low (45 kg propane ha⁻¹) propane dose. In each treatment, one subplot was hand-weeded in addition to flame treatment to remove differential weed effects, while the other received only the prescribed flame weeding regimen as weed control. Overall, control of broadleaf weeds was better than that of grass species. Broadleaf weed density and shoot mass were reduced as propane dose and the number of flame treatments increased. Grass density was reduced by 50% in all flamed treatments compared to the non-treated control, but no differences between flamed treatments were observed. Effects of flame treatments on grass shoot mass were minimal. Among weed-free treatments, onion was able to tolerate up to six flame treatments at either dose without a loss of yield. Treatments that received only flame weeding as weed control had total onion yields 37 and 80% of the weed-free flamed treatments in 2006 and 2007, respectively. Flame weeding treatments had little effect on the time to reach maturity, onion pungency, or quercetin concentration.     

Nitrogen fertilization and irrigation affects tuber characteristics of two potato cultivars

Nitrogen fertilization, irrigation, and cultivars affect tuber characteristics such as tuber size, specific gravity, and N concentration. Few studies, however, have investigated the interaction of irrigation and N fertilization on the tuber characteristics of potato cultivars, particularly in Atlantic Canada. The objective of this on-farm study, conducted at four sites in each of three years, 1995 to 1997, was to determine the effects of supplemental irrigation and six rates of N fertilization (0-250 kg N ha^-1) on the number of tubers per plant, the average fresh tuber weight, tuber N concentration, nitrate (NO₃-N) concentration, and specific gravity of the cultivars Shepody and Russet Burbank. Nitrogen fertilization increased the average fresh tuber weight, tuber N and N0₃-N concentrations, and decreased specific gravity. Effects of increasing N fertilization on tuber characteristics were often more pronounced for Shepody than for Russet Burbank, and for irrigated than for non-irrigated conditions. Shepody had greater average fresh tuber weight and tuber N concentration, lower specific gravity, and fewer tubers per plant than Russet Burbank. Supplemental irrigation increased the average fresh tuber weight and the number of tubers per plant, but it had a limited effect on specific gravity and tuber N and NO₃-N concentrations. Tuber NO₃-N con centration and specific gravity were strongly related to tuber N concentration, which in turn depended primarily on N fertilization. Incidents of lowest specific gravity and highest NO₃-N concentration occurred with a relative yield close to or equal to 1.0. We conclude that the risks of low specific gravity and high tuber NO₃-N concentration are greater when fertilization exceeds the N requirements to reach maximum tuber yield.     

受控环境下光周期对小麦生长发育、产量及营养品质的影响

为探讨受控生态生保系统(CELSS)中利用光周期调控提高植物能量利用效率的可能性,以红蓝LED(90%红+10%蓝)为光源,在开花前及开花后各设置12、16、20和24h四个光周期水平,形成16个处理,研究光周期对小麦生长发育、产量和营养品质的影响。结果表明,开花前光周期延长使小麦开花时间显著提前,特别是导致出苗到拔节和拔节到抽穗的天数显著减少。开花后光周期延长会缩短开花到成熟的时间,且开花前和开花后光周期对小麦生育期长度的影响相互独立。在开花前,短光周期有利于小麦营养器官的构建,增加株高、分蘖数、叶片数和营养器官干重,进而提高籽粒产量、收获指数和能效比。在开花后,长光周期提高了灌浆期叶片光合速率,促进籽粒中干物质积累,提高籽粒产量、收获指数和能效比。开花前短光周期的增产作用主要是因穗数和穗粒数增加,而开花后长光周期的增产作用主要是因粒重增加。在开花前后,延长光周期均导致籽粒淀粉含量增加和蛋白质含量减少。在开花前12h光照、开花后24h光照的处理下小麦产量和能量利用效率均最高,说明开花前短光周期结合开花后长光周期最有利于小麦高产和能量高效利用。     

Synthesis and Structure Properties of Flame Retardant and Cationic Dyeable Polyamide 6 Modified with 5-sulfoisophthalic Acid Sodium and Melamine Cyanurate

Unmodified polyamide 6 commonly dyed with acid dyes, and has no flame-retarded properties. So they are flammable and can be easily stained by foods or drinks that contain acid dyes. However, the acid groups react with amino groups that existed at the end of PA6 chain while using cationic dyes. Thus, the acid dyes can be washed immediately. In this study, the flame retardant and cationic dyeable polyamide 6 (FRCD-PA6) modified with 5-sulfoisophthalic acid sodium (5-SSIPA) and melamine cyanurate (MCA) was successfully prepared by the two-step-melt polymerization method. Firstly, cationic dyeable polyamide 6 (CD-PA6) was prepared with sodium salt from 5-sulfoisphthalic acid. Secondly, melamine cyanurate, as an efficient flame retardant, was blended into the reaction. The chemical and crystalline structures of FRCDPA6 were characterized by the Fourier transform infrared spectroscopy (FT-IR) and wide angle X-ray diffraction (XRD). Their thermal properties were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and morphology was analyzed by SEM, respectively. It had been measured to prove the dispersion of 5-SSIPA and MCA on polyamide 6 matrix. Incorporating with 5-SSIPA created more amorphous regions and rose up the dyeing rate easily, with a highest dyeing rate for about 96.79 %. The effect of varying MCA content on the composites showed more flame retardant and made better heat-resistance. Moreover, with the appropriate addition of MCA content, the limit oxygen index (LOI) reached up to 27, less smoking, no more black smoke, droplet phenomenon was slightly, and flame resistance had greatly improved. Because of the good synergy between 5-SSIPA and MCA, a kind of novel modified polyamide 6 which own both cationic dyeable and efficient flame retardant properties was born.     

Encapsulation of phase change materials by complex coacervation to improve thermal performances and flame retardant properties of the cotton fabrics

This paper reports a study on the thermal stability and flame-retardant properties of microencapsulated phase change materials (PCMs) with clay nano-particles (Clay-NPs) doped gelatin/sodium alginate shell. The novel microcapsules were fabricated by the technique of complex coacervation using gelatin and sodium alginate as the shell and PCM n-eicosane as the core. Their flame retardant property as well as their practicable thermal performances when incorporated into woven cotton fabrics by pad-dry-cure were investigated. Thermal storage/release properties of the prepared microcapsules were analyzed using DSC instrument. Thermal gravimetry (TG) analysis was performed to measure the thermal stability and surface morphology of the microcapsules was observed by means of optical microscopy and SEM. The DSC results indicated that the latent heat storage capacity of prepared microcapsules changed in range of 97-114 J/g. The microcapsules had spherical shape with particle sizes between 1.37 μm and 1.6 μm. The PCM microcapsules (PCMMs) and nano-composite PCM microcapsules (NCPCMMs) with clay-NPs doped gelatin/sodium alginate shell were found to have good potential for developing thermal comfort in textiles. Comparing with conventional PCMMs, NCPCMMs have significantly better thermal stability. Nano-composite structure of the NCPCMMs, in which clay-NPs doped in the polymeric shell structure, attributed to increase the shell thermal stability. Improved flame retardant properties of the cotton fabrics treated with NCPCMs were declared as a result of flame retardant tests. Thermo-regulating properties of the fabrics were proved by thermal history (THistory) measurement results from releasing heat from microcapsules.     

Seed Treatment with Uniconazole Powder Improves Soybean Seedling Growth under Shading by Corn in Relay Strip Intercropping System

The relay strip intercropping system of wheat-corn-soybean is widely used in southwest China. However, it is hard to obtain a stable production of soybean with this system, since soybean plants grow under shading by corn; the stems are thinner and susceptible to lodging. We examined the effects of seed treatment with uniconazole powder (0, 2, 4 and 8 mg kg-¹ seed) on the growth of soybean seedlings under relay strip intercropping, some morphological characteristics and yield. The seedling height, first internode length, cotyledonary node height and leaf area per plant were decreased, while the stem diameter, root dry weight, shoot dry weight, root volume, leaf greenness and root to shoot dry weight ratio were increased by uniconazole treatment. The root vigor and root active absorption area were also increased significantly by uniconazole treatment. Moreover, 2 and 4 mg kg-¹ uniconazole powder treatment increased shoot dry weight, number of pods per plant, number of seeds per pod and seed yield significantly. Thus, the results suggested that seed treatment with uniconazole powder at a suitable concentration can improve soybean seedling growth, resist the lodging and also increase the seed yield under shading by corn in relay strip intercropping system.     

Investigation on flame retardancy of poly(ethylene terephthalate) for plastics and textiles by combination of an organo-modified sepiolite and Zn phosphinate

Zn phosphinate, organo-modified sepiolite and poly(ethylene terephthalate) (PET) have been melt blended to develop a new flame retardant system for PET plastics and textiles. The combination of Zn phosphinate and sepiolite have been exploited in order to enhance the flame retardancy of PET for both plastics and textiles. The thermal stability of PET blends evaluated by thermogravimetric analysis and differential scanning calorimetry results remarkably affected by the loaded fillers. The combustion tests by cone calorimetry reveal a relevant decrease of combustion rate and a high increase of fire performance index for both plastics and textiles due to the presence of this novel flame retardant mixture. Analogously, limiting oxygen index has been found increased in a remarkable way.     

叶面锌肥对紫粒小麦产量及品质的影响

为明确叶面施锌肥对紫粒小麦产量及品质的影响,选用小麦山农紫（紫粒）和山农129（红粒）为试验材料,采用大田试验,设置不施锌肥（Zn₀,对照）、叶面喷施锌肥10 kg·hm^-2（Zn_{10）、20 kg·hm^-2（Zn20）、30 kg·hm^-2（Zn30）、40 kg·hm^-2（Zn40）5个处理,分析了不同施锌量下紫粒小麦产量和品质相关指标的异同。结果表明,与不施锌肥比较,叶面施锌肥后山农129和山农紫分别增产1.4%~4.7%和2.3%~5.2%;随着施锌量的增加,山农129和山农紫的籽粒锌含量、总蛋白含量及蛋白质产量均表现出先增后降的趋势,分别在Zn30和Zn20处理下达到最高值,比Zn0分别提高25.8%、1.2%、16.8%和44.1%、2.1%、20.1%。两品种叶面施锌肥较其对照显著提高了籽粒蔗糖含量、湿面筋含量、面筋指数（P<0.05),但总淀粉和可溶性糖含量无显著性差异;总体上,山农紫小麦增幅大于山农129。综上所述,本试验条件下,叶面喷施锌肥可提高紫粒小麦产量、锌含量以及营养品质,以喷施锌肥20 kg·hm^-2较佳。}     

外源GA3对小黑麦籽粒灌浆特性及产量的影响

小黑麦籽粒不饱满是制约其应用开发的主要因素。为了解决这个问题,本试验以小黑麦东农8809和东农95-6654为试验材料,研究外源赤霉素(GA3)作用下小黑麦籽粒干物质、灌浆速率及产量的变化,并探讨开花期喷洒外源赤霉素对小黑麦籽粒灌浆特性及产量的影响。结果表明,开花期适量赤霉素处理能提高小黑麦籽粒灌浆速率,加速籽粒灌浆进程,促进干物质向籽粒中运转,进而提高粒重及产量。20 mg·L-1赤霉素喷施调控效果最好。     

玉米偏垄宽窄行种植方式的增产作用和生理特性研究

以辽宁省主栽玉米品种沈玉21为试验材料,进行偏垄宽窄行种植方式的研究。试验以常规种植方式为对照,研究偏垄宽窄行种植方式的增产效果、生理指标变化和群体结构特点。结果表明,偏垄宽窄行种植方式单位面积产量显著高于常规种植,粒重与穗粒数明显增加,生物产量提高;偏垄宽窄行种植方式改善了玉米冠层结构,特别是明显改善了冠层中下部通风透光条件;偏垄宽窄行种植方式叶面积指数增大且持续时间较长,冠层内CO₂浓度明显增加。