The Experimental and Numerical Studies on Gas Production from Hydrate Reservoir by Depressurization

A set of experimental system to study hydrate dissociation in porous media is built and some experiments on hydrate dissociation by depressurization are carried out. A mathematical model is developed to simulate the hydrate dissociation by depressurization in hydrate-bearing porous media. The model can be used to analyze the effects of the flow of multiphase fluids, the kinetic process and endothermic process of hydrate dissociation, ice-water phase equilibrium, the variation of permeability, convection and conduction on the hydrate dissociation, and gas and water productions. The numerical results agree well with the experimental results, which validate our mathematical model. For a 3-D hydrate reservoir of Class 3, the evolutions of pressure, temperature, and saturations are elucidated and the effects of some main parameters on gas and water rates are analyzed. Numerical results show that gas can be produced effectively from hydrate reservoir in the first stage of depressurization. Then, methods such as thermal stimulation or inhibitor injection should be considered due to the energy deficiency of formation energy. The numerical results for 3-D hydrate reservoir of Class 1 show that the overlying gas hydrate zone can apparently enhance gas rate and prolong life span of gas reservoir.

Site-directed PEGylation of trichosanthin retained its anti-HIV activity with reduced potency in vitro

Trichosanthin (TCS) was the first ribosome inactivating protein found to possess anti-HIV-1 activity. Phase I/II clinical trial of this compound had been done. Antigenicity and short plasma half-life were the major side effects preventing further clinical trial. Modification of TCS is therefore necessary to revive the interest to develop this compound as an anti-HIV agent. Three potential antigenic sites (Ser-7, Lys-173, and Gln-219) were identified by computer modeling. Through site-directed mutagenesis, these three antigenic amino acids were mutated to a cysteine residue resulting in 3 TCS mutants, namely S7C, K173C, and Q219C. These mutants were further coupled to polyethylene glycol with a molecular size of 20 kDa (PEG) via the cysteine residue. This produced another three TCS derivatives, namely PEG(20)k-S7C, PEG(20)k-K173C, and PEG(20)k-Q219C. PEGylation had been widely used recently to decrease immunogenicity by masking the antigenic sites and prolong plasma half-life by expanding the molecular size. The in vitro anti-HIV-1 activity of these mutants and derivatives was tested. Results showed that the anti-HIV-1 activity of S7C, K173C, and Q219C was decreased by about 1.5- to 5.5-fold with slightly lower cytotoxicity. On the other hand, PEGylation produced larger decrease (20- to 30-fold) in anti-HIV activity. Cytotoxicity was, however, weakened only slightly by about 3-fold. The in vitro study showed that the anti-HIV activity of PEGylated TCS was retained with reduced potency. The in vivo activity is expected to have only slightly changed due to other beneficial effects like prolonged half-life. (C) 2004 Elsevier Inc. All rights reserved.

Growth and antioxidant system of Escherichia coli in response to microcystin-RR

Microcystins are a kind of cyclic hepatoxins produced by many species of cyanobacteria. The toxic effects of microcystins on animals and plants have been well studied. However, the reports about the effects of microcystins on microbial cells are very limited. In present paper, Escherichia coli was undertaken to determine the effect of microcystin-RR. These results suggested that microcystin-RR could prolong the growth of E. coli when exposed to high concentrations of microcystin-RR and cause the accumulation of ROS and induce the oxidant stress for a short time. The antioxidant system protects E. coli from oxidative damage.

Range-wide Yangtze freshwater dolphin expedition: The last chance to see Baiji?

Background, Aim and Scope. There are two species of fresh water cetaceans surviving in the Yangtze River system in China: Baiji (Lipotes vexillifer) and Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis). As a result of the expansion of human activities on the river, their distribution ranges appear to be decreasing and in the case of the Baiji, are even being restricted to several sections. The Baiji is the world's most critically endangered cetacean species with a population estimated at only a few tens of individuals. The Yangtze finless porpoise is the world's only freshwater-adapted population of the species, and it has been estimated that only around 1,000 individuals remain in the river system. In order to prevent the extinction of Baiji and a sharp decline in the abundance of the porpoise, in situ conservation (i.e. in the river) and two ex situ conservation (i.e. in semi-natural reserves and in captivity) strategies were proposed and have been implemented since the early 1990s. In view of both the severely endangered status of the animals and the severely degraded conditions of their habitats, the feasibility and actual status of these two strategies are raised for discussion. Main Features. The threats faced by the cetaceans are mainly from the unfettered exploitation of the river's resources. In the past 20 years, five nature reserves have been established along the river. Imposing maximum prohibition of harmful and illegal fishing methods in the reserves might prolong the process of extinction of these cetaceans in the wild, but so far, the administrative measures taken in the reserves have not yet kept the abundance from sharply declining. As human use of the river and its resources is expected to intensify for many decades into the future, the ability of the river to continue to support these species is certainly undecided. Therefore, rescuing animals from the river and establishing viable breeding populations in semi-natural reserves, in which the environment is similar to the main stream of the river, and in captivity, has to be considered urgently as the short-term goal of ex situ strategies. Since the abundance of porpoises is higher than that of the Baiji, we have first established breeding populations of them in the semi-natural reserves and in captivity. But, considering the extremely low density of Baiji in the river, an immediate range-wide Yangtze Baiji survey is an urgent need for locating and capturing sufficient Baiji for successfully establishing a breeding population of them in semi-natural reserves. Results. Two semi-natural reserves (in Shishou, Hubei Province, and Tongling, Anhui Province) have been set up along the river in order to establish breeding populations of the Baiji and the porpoises. So far, several small groups of porpoises that were caught in the main stream of the river have successively been introduced into the semi-natural reserves. Under careful management, these animals in both of the semi-natural reserves not only survive, but can also reproduce naturally and successfully. At least one or three calves were born in each reserve each year. Additionally, a breeding group of porpoises is being established at the Baiji Dolphinarium at the Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan. There are presently four adults and one calf living in the Dolphinarium. The calf, born in July, 2005, is the first captive bred Yangtze Finless Porpoise in the world. In preparation for the range-wide Yangtze cetacean survey, a 9-day pilot expedition on the river near Wuhan was conducted in March, 2006, in order to develop methods for locating the Baiji. No Baiji were expected to be seen in such a short period but about 40 porpoise sightings were observed. Results of the pilot survey indicated that traditional visual and acoustical survey methods for cetaceans should be adapted to find the elusive Baiji in the river. Currently, the range-wide Yangtze cetacean survey is in preparation. The survey will cover over 1,700 km of the Yangtze River from Yichang to Shanghai, and is expected to provide detailed information on Baiji and porpoise numbers and distribution patterns in the river. Discussion. Although the short-term goal of ex situ conservation is to rescue cetaceans from the river and to establish viable breeding populations in semi-natural reserves and in captivity, the long-term goal of releasing the animals back into the river when the threats have decreased and the natural environment has been improved, should not be neglected. Moreover, the in situ conservation efforts in the natural reserves, and even in the entire Yangtze River system, including the lakes, should not be ignored or abandoned at any time. The activities contributing to the conservation of the Baiji and the porpoise in the wild have the incidental effect of benefiting the entire Yangtze ecosystem and other rare threatened species. The dynamics of the groups of porpoises in semi-natural reserves should be monitored continually, in order to guide the establishment of breeding groups of Baiji in these semi-natural reserves in the near future. Conclusions. Under the existing severely degraded conditions of the Yangtze system, the sharply fall populations of Baiji and porpoises will not be suspended in the foreseeable future. Therefore, ex situ conservation should be emphasized, and the severely threatened Baiji in the river should be removed and translocated to semi-natural reserves for establishing viable breeding populations. The successful program of capturing, translocating and maintaining finless porpoises in the Shishou semi-natural reserve has demonstrated its adequacy as an ex situ environment for cetaceans. Following the successful pilot survey in the river, the immediate range-wide Yangtze cetacean survey is proposed and is in preparation. The range-wide survey is expected to ensure that any remaining Baiji can be found reliably and captured successfully after the survey. Recommendations and Perspectives. During the range-wide survey, not only the Baiji but also the porpoise as well as their habitats should be investigated based on visual and acoustical methods that adapted to the river and the animals. Meanwhile, the current risk levels to the Baiji and porpoises should be evaluated at each area where Baiji or porpoises can be reliably sighted. Any capture efforts should be targeted on the most threatened areas, or where there is maximum risk of injury or death. The immediate track of the Baiji should be carried out once a Baiji is sighted during the range-wide survey in order to obtain the movement route of the animals, which is crucial information for the successful capture operation. Additionally, the need to establish new semi-natural reserves for the porpoises should be placed on the agenda of local and central governments in the near future.

Dephasing rate in an InAs/GaAs single-electron quantum dot qubit

We have obtained the parameter-phase diagram, which unambiguously defines the parameter region for the use of InAs/GaAs quantum dot as two-level quantum system in quantum computation in the framework of the effective-mass envelope function theory. Moreover, static electric field is found to efficiently prolong decoherence time. As a result, decoherence time may reach the order of magnitude of milli-seconds as external static electric field goes beyond 20 kV/cm if only vacuum fluctuation is taken as the main source for decoherence. Our calculated results are useful for guiding the solid-state implementation of quantum computing.

InAs/GaAs single-electron quantum dot qubit

The time evolution of the quantum mechanical state of an electron is calculated in the framework of the effective-mass envelope function theory for an InAs/GaAs quantum dot. The results indicate that the superposition state electron density oscillates in the quantum dot, with a period on the order of femtoseconds. The interaction energy E-ij between two electrons located in different quantum dots is calculated for one electron in the ith pure quantum state and another in the jth pure quantum state. We find that E-11]E-12]E-22, and E-ij decreases as the distance between the two quantum dots increases. We present a parameter-phase diagram which defines the parameter region for the use of an InAs/GaAs quantum dot as a two-level quantum system in quantum computation. A static electric field is found to efficiently prolong the decoherence time. Our results should be useful for designing the solid-state implementation of quantum computing. (C) 2001 American Institute of Physics.

牦牛粪便对青藏高原东部高寒草甸土壤养分系统的影响

川西北高寒草甸位于青藏高原东部地区，是我国四大牧区之一，也是长江和黄河等江河源区的重要水源涵养功能区。近几十年来，大量牦牛粪便被牧民作为生物能源、肥料或者食用菌产业的原料而利用，为草原生态系统的养分平衡增加了生态风险。鉴于在青藏高原地区针对牦牛粪便的相关研究尚未见报道，本文从粪便和土壤养分相互变化趋势的角度出发，研究了粪便在夏秋两季的分解状况和粪便其下及其周围土壤的养分变化。通过此研究，将有助于了解牦牛粪便在自然状态下的分解速率以及粪便对土壤养分及土壤微生物生物量的影响，为粪便对草地土壤生态系统的贡献提供概念性认识，同时也为高寒草甸草地这种脆弱生态系统的可持续管理提供理论依据。 针对牦牛粪便自身养分释放及其对土壤在时间和空间尺度上的影响，本文通过模拟牛粪堆积，在不同时间和固定区域内对牛粪和土壤进行了夏秋两季的采样测定，分析了牛粪及土壤NO3--N、NH4+-N、速效K、无机P、有机C、全N 和全P 含量随时间的变化趋势。得到如下结果： 1. 在研究区域内，牛粪对草地生态系统具有较强的养分（N、P）贡献能力。据初步统计，其估值大致为氮素699~932 kg ha-1，P 素为110~147 kg ha-1。牛粪（湿重、干重）在夏秋季节的分解速率具有较大差异，夏季显著快于秋季。夏季牛粪湿重、干重在2 个月左右之后分别降为初期的14%和24%，而秋季同期分别降为35%和52%。牛粪养分（NO3--N、NH4+-N、速效K、无机P、有机C、全N 和全P）的分解速率在夏季也要显著快于秋季。秋季经过2 个月左右的分解之后，牛粪以上含量分别降至初始态的32%、60%、36%、64%、58%、63%和43%，远高于夏季的同期水平。 2. 在不同季节，牛粪周围的土壤养分（NO3--N、NH4+-N、速效K 和无机P）含量变化随时间改变呈现相同的趋势。但是，牛粪周围不同远近下土壤养分随时间的动态变化幅度略有不同。粪下土壤养分含量随时间变化波动较大，距粪便越远，随时间变化的变幅越为平缓。总体来说，在夏季由于粪便分解较快，对土壤养分的持续作用时间不及秋季，秋季粪便分解变慢，表现出养分的缓释特征。其次，牛粪对粪下土壤影响的持续时间也长于对周围土壤的作用时间。 3. 粪便对土壤养分（NO3--N、NH4+-N、速效K、无机P）影响的范围在不同季节具有差异。夏季要高于秋季，但对周围土壤养分影响的持续时间低于秋季。在夏季短期内，牛粪对土壤NO3--N 和速效K 含量的影响范围能够超过30cm，而对NH4+-N 和无机P 的影响范围则介于10cm 和30cm 之间。在2 个月左右之后，牛粪对周围土壤养分的影响能力基本消失。在秋季，牛粪对周围土壤养分影响范围难以达到30cm 处。粪便在夏季对其下土壤和周围土壤的有机C、全N 和全P 含量并无显著影响，但在秋季能显著增加其下土壤有机C、全N 和全P 含量。 4. 牛粪在秋季对土壤SMB-C、SMB-N 和SMB-P 含量的影响能够持续2 个月以上，由于秋冬季节牛粪分解缓慢，因此推断这种效应持续时间至少能够1 年左右。另一方面，牛粪在秋季对土壤SMB-C、SMB-N 和SMB-P 含量的影响范围主要集中在其下土壤，而周围的影响效应并不明显。 The grassland on the eastern fringe of Qinghai-Tibetan Plateau was one of the four greatest pasture zones in our country and the main water conservation function zones in the hesastream of Yangtse River and Huanghe river. Rencent years, lots of dung in this area was used as biological energy, fertilizer or material of fungoid growing, leading to high risk of nutrient banlance in grassland ecosystem. In view of the researches on the impact of yak dung in this area are relatively rare, the present study focused on the relationship of dung and soil nutrient transformation in sunmer and autumn, which could profoundly illuminate the mechanism of dung decomposition and the effect of dung on soil chemical properties and soil microbe biomass. The present study also contributed to a basic understand and provided scientific management in the high-frigid ecosystem. Decomposition of yak dung and its effect on soil chemical properties in eastern grassland of Qinghai-Tibetan Plateau were determined. The study simulated the real dung pats, took dung and soil samples at different time and fixed-point in summer and autumn. The samples were analysed for NO3--N, NH4+-N, available K, inorganic P, total organic C (TOC), total N (TN), total P (TP). It was concluded that: 1. In study area, the yak dung supplied to ecosystem substantial nutrient. It is estimated that the N contribution of dung was approximately 699~932 kg ha-1, P contribution was approximately 110~147 kg ha-1. The rate of yak decomposition was more rapid in summer than autumn, the wet and dry weight of yak decreased to 14% and 24% respectively after 2 months when dung excreted in summer, with 35% and 52% in autumn. The content of NO3--N、NH4+-N、available K、inorganic P、TOC、TN and TP in dung decomposed more rapid in summer too. After 2 months when dung excreted in autumn, the content of above nutrient decreased to 32%、60%、36%、64%、58%、63% and 43% respectively，which were significantly higher than summer. 2. The content of NO3--N、NH4+-N、available K and inorganic P in soil around dung had the same transformation trend in each season, whereas it was distinguishing at different gradient of distance from dung, the nutrient in soil below dung had the most significant change while the more far from dung, the less change in soil. It was concluded that the yak dung had prolong impacts on soil in autumn compared with summer, besides, it aslo showed that the yak dung had protract effect on soil below dung compared with soil around dung. 3. The yak dung had expansive impact on soil around dung in summer whereas had relatively short effect compared with autumn. In short-term at summer, there was a significant increase about the content of NO3--N and available K around 30cm radius from dung pat while the content of NH4+-N and inorganic P between 10cm to 30cm. After 2 months, the impact almost disappeared. In autumn, the effect was hard to reach 30cm. The yak dung had no significant effects on the content of TOC、TN and TP in soil below or around dung in summer whereas there was a obvious increase in soil below dung pat in autumn. 4. The duration of effect of yak dung on soil microbial biomass(SMB) C、N and P was at least 2 months, maybe even more than 1 year. On the other hand, the impact of dung on SMB-C、SMB-N and SMB-P mainly acted on soil below dung while no obious effect on soil around dung.

Room-temperature strategy for networked nonspherical gold nanostructures from Au(III)-[G-2]-CO2H dendrimer complex

The present work describes a convenient approach to fabricate networked nonspherical gold nanostructures by using [G-2]-CO2H dendrimer and toluene as capping and bridging agents in a CH2Cl2 and H2O biphasic system. A controlled linear assembly is achieved without the use of any catalyst at room temperature. UV-vis spectrum, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) analysis show that the product is well networked nanostructures with diameter of 4-10 nm and consists of coalesced face-centered cubic gold nanocrystals. Extended experiments reveal that both benzene and dimethylbenzene can also inhabit the gold ions to make them crosslinked, prolong the nucleation points and eventually facilitate the formation of the networks.

三类新型壳聚糖衍生物的制备及其抑菌、抗氧化活性研究

本论文制备了三类新型壳聚糖衍生物，并对其抑菌及抗氧化活性进行了筛选与研究，具体结果如下。 通过在不同分子量的壳聚糖上引入1，3，5-噻二嗪硫酮首次合成壳聚糖噻二嗪硫酮衍生物（N-2-对氨基苯磺酰噻二嗪硫酮-壳聚糖（SATTCS）， N-2-邻甲基苯噻二嗪硫酮-壳聚糖（TITTCS）, N-2-邻氯苯噻二嗪硫酮-壳聚糖（CITTCS））；通过将羟丙基壳聚糖与不同的醛反应首次合成了羟丙基壳聚糖希夫碱（羟丙基壳聚糖水杨醛希夫碱（HHPCS）, 羟丙基壳聚糖5-氯水杨醛希夫碱（HCHPCS）, 羟丙基壳聚糖5-硝基水杨醛希夫碱（HNHPCS）, 羟丙基壳聚糖5-溴水杨醛希夫碱（HBHPCS）, 羟丙基壳聚糖糠醛希夫碱（FHPCS））；通过将不同分子量的壳聚糖与乙酰芳香胺反应首次合成了壳聚糖乙酰芳香胺衍生物（壳聚糖乙酰苯胺（ABCS）, 壳聚糖乙酰芳邻氯苯胺（ACCS），壳聚糖乙酰芳对甲苯胺（TDCS）, 壳聚糖乙酰甲萘胺（MDACS））。采用红外、元素分析等方法进行了结构鉴定。 通过对金黄色葡萄球菌、八叠菌、大肠杆菌、绿脓杆菌，芦笋茎枯病菌等一些真菌的抑菌活性研究表明：壳聚糖噻二嗪硫酮衍生物、壳聚糖乙酰芳香胺衍生物具有较好的抑制细菌的活性，且衍生物对金黄色葡萄球菌的抑制效果最好。分子量不同，抑菌活性也不同。其中，SATTCS和 LMANCS对细菌的抑制效果最好， SATTCS和TDCS的对真菌的抑菌活性最为显著。 抗氧化活性筛选结果表明：壳聚糖噻二嗪硫酮衍生物和羟丙基壳聚糖希夫碱具有很强的清除羟自由基的能力，清除能力全部优于Vc: 壳聚糖噻二嗪硫酮衍生物还具有较强的还原能力,其中TITTCS的还原能力比Vc强；并且，低分子量的壳聚糖噻二嗪硫酮衍生物的清除羟自由基的能力以及还原能力略强于高分子量的壳聚糖噻二嗪硫酮衍生物。 通过本研究工作制备了三类新型壳聚糖衍生物；生物活性研究表明：壳聚糖噻二嗪硫酮衍生物和壳聚糖乙酰芳香胺衍生物在抑菌方面具有应用潜力。研究成果对深入开发利用甲壳质资源，促进我国海洋药物的发展具有重要的意义。

Study on extraction of agaropectin from Gelidium amansii and its anticoagulant activity

Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg.d in rats for 15 days, TT (thrombin time), CT (coagulation time), PT (prothrombin time), and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.

Corrosion behaviour of steel in beach soil along Bohai Bay

Research on corrosion of steel structures in various marine environments is essential to assure the safety of structures and can effectively prolong their service life. In order to provide data for anticorrosion design of oil exploitation structures in the Bohai Bay, the corrosion behaviour and properties of steel in beach soil, using typical steel samples (Q235A carbon steel and API 5Lx52 pipeline steel) buried 0.5, 1.0 and 1.5 m deep under typical beach soils in Tanggu, Yangjiaogou, Xingcheng, Yingkou and Chengdao for 1-2 years were studied. The carbon steel and pipeline steel were both corroded severely in the beach soil, with the form of corrosion being mainly uniform with some localised attack (pitting corrosion). The corrosion rate of the carbon steel was up to 0.16 mm/year with a maximum penetration depth of 0.76 mm and that of the pipeline steel was up to 0.14 mm/year, with a maximum penetration depth of 0.53 mm. Compared with carbon steel, the pipeline steel generally had better corrosion resistance in most test beach soils. The corrosion rates and the maximum corrosion depths of carbon steel and pipeline steel were in the order: Tanggu>Xingcheng>Chengdao>Yingkou>Yangjiaogou with corrosion altering with depth of burial. The corrosion of steel in the beach soil involves a mixed mechanism with different degrees of soil aeration and microbial activity present. It is concluded that long term in situ plate laying experiments must be carried out to obtain data on steel corrosion in this beach soil environment so that the effective protection measures can be implemented.

污泥处理经济评价和污泥堆肥中氧气监测与动态分析

With the continually increase both in the amount of wastewater disposal and in the treatment rate, more and more sewage sludge has been produced. An economic estimate was taken on the different sewage sludge disposal and treatment technologies, and led to the conclusion that compost is an effective way to make sewage sludge harmless, stable and resourceable. Normally, there are several ways to treat sewage sludge, such as landfill, compost, incineration and so on. These technologies will cost 300-1000 Y per ton of sludge. Among those ways, landfill is the cheapest one and operates easily, however, it just postpones the pollution instead of eventually eliminating the pollution; The amount of the sludge will reduce dramatically after incineration, while incineration will take a very high investment in the beginning, at the same time, it's very hard to maintain running; Sewage sludge will be resourceful after composting treantment, thus makes up the treatment cost, makes composting is the most economical way. Compost production is safe when correctly used, compost is a important way to treat sewage sludge. Oxygen is an important control factor in aerobic composting that has great effects on temperature and microorganisms. The gas gathering and transfering system of an online oxygen monitoring system for composting were bettermented to prolong the monitoring system's running period. The oxygen concentration changes in various aerobic composting stage were studied, and conclusions came to that oxygen concentration changes much faster in the oxygen concentration increasing stage than that in the declining stage; the better the aerobic condition is, the sooner the monitoring system starts to work. The minimal oxygen concentration during a ventilation cycle often falls at the beginning, then ascends in the composting period; at the same time, oxygen concentration changes fast in the early composting stage(temperature increasing stage), much slower in the middle stage(continouns thermophilic stage),and seldom changes in the late composting stage(temperature declining stage). With the help of the oxygen realtime-online monitoring system, oxygen concentrations was measured. During the composting period, water contents was analyzed after sampled. It's found that water contents (WC) and Oxygen concentration can both influence the composting process, and the control rule varies in the various composting stages. Essentially, the rule that water and oxygen control the composting process comes from water counterchecks the oxygen transferring to the composting substrate. The most influential factor to the WC and to the oxygen is the components in the composting pile. In the temperature increasing stage, seldom microorganisms exist in the composting pile with low activity, thus oxygen can meet with microorganisms' need, and WC is the dominant factor. In the high temperature (continouns thermophilic) stage, composting process is controlled by WC and oxygen, essentially by WC, at the same time, their influence somehow is not remarkable. In the temperature declining stage, WC and oxygen influence the composting process little. It's also found that the composting process will differ even if under the same components, thus to equably mix the components can avoid WC focusing in some place and let the composting pile to be aerobic. In one sentence, aerobic state is the most important factor in the composting process, suitable bulking material will be useful to the composting control.