Effect of Agitator’s Types on the Hydrodynamic Flow in an Agitated Tank

The aim of this paper is to study the effect of agitator’s types on the turbulent flows in stirred tanks without and with baffles.The hydrodynamics behavior induced by four different agitator’s types:a Rushton turbine(RT),a circular blade turbine(CBT),a diverging triangular blade turbine(DTBT)and converging triangular blade turbine(CTBT)are numerically predicted by solving the Navier-Stokes equations and RNGκ–εturbulent model.The simulations are carried out using the Multi Reference Frame(MRF)approach.The numerical results showed good agreement with experiment.We find that the agitator CTBT gives an important profit on the power consumption per report/ratio the others and DTBT give a good reduction of the vortex size of the impeller angles.

Simulation of drop breakage in liquid–liquid system by coupling of CFD and PBM: Comparison of breakage kernels and effects of agitator configurations

This work focuses on drop breakage for liquid-liquid system with an adoption of numerical simulation by using computational fluid dynamics and population balance model (PBM) coupled with two-fluid model (TFM). Two different breakage kernels based on identical breakage mechanism but different descriptions of breaking time are take n into account in this work. Eight cases corresp on ding to distinct configurations of agitator are carried out to validate numerical predictions, namely agitators with different porosity and hole diameters, respectively implemented in Cases 1 to 5 and Cases 6 to 8. The results are compared with experimental data for testing the applicability of both kernels. Simulations are implemented, in this work, with an approach of class method for the solution of population balance model by the special-purpose computational fluid dynamics solver Fluent 16.1 based on finite volume method, and the grids used for meshing the solution domain are accomplished in a commercial software Gambit 2.4.6. The effects of configurations of agitator corresponding to different parameters mentioned above on final Sauter mean diameter are equally concentrated in this work. Analysis of both kernels and comparisons with experimental results reveal that, the second kernel has more decent agreement with experiments, and the results of investigations on effects of agitator configurations show that the in fluences of these parameters on Sauter mean diameter are marginal, but appropriate porosity and hole diameter are actually able to decrease Sauter mean diameter. These outcomes allow us to draw general conclusions and help investigate performances of liquid-liquid system.

Variation law of gas holdup in an autoclave during the pressure leaching process by using a mixed-flow agitator

The multiphase reaction process of pressure leaching is mainly carried out in the liquid phase. Therefore, gas holdup is essential for the gas–liquid–solid phase reaction and the extraction rate of valuable metals. In this paper, a transparent quartz autoclave, a six blades disc turbine-type agitator, and a high-speed camera were used to investigate the gas holdup of the pressure leaching process. Furthermore, experiments determining the effects of agitation rate, temperature, and oxygen partial pressure on gas holdup were carried out. The results showed that when the agitation rate increased from 350 to 600 r/min, the gas holdup increased from 0.10% to 0.64%. When the temperature increased from 363 to 423 K, the gas holdup increased from 0.14% to 0.20%. When the oxygen partial pressure increased from 0.1 to 0.8 MPa, the gas holdup increased from 0.13% to 0.19%. A similar criteria relationship was established by Homogeneous Principle and Buckingham's theorem. Comprehensively, empirical equation of gas holdup was deduced on the basis of experimental data and the similarity theory, where the criterion equation was determined as ε=4.54×10^(-11)n^(3.65)T^(2.08)P_g^(0.18). It can be seen from the formula that agitation rate made the most important impact on gas holdup in the pressure leaching process using the mixed-flow agitator.

AN INNOVATED REACTOR WITH VARYING DIAMETER AGITATOR AND ITS APPLICATIONS

The reactor is equipped with two different types of agitators: the diameter-variable agitator and the two-pitched-paddle agitator. The diameter of the former can be varied according to the requirement of the chemical reactions, thus making the concentration and temperature of the whole reaction system uniform throughout the reactor without any stagnant zone. It is shown that the apparatus has the preponderance over conventional agitator, especially when extremely rapid reactions are accompanied by large amount of reaction heat and when the viscosity of the reaction system varies in a wide range. The reactor is very effective when applied to the polycondensation reaction between paraphenylene diamine （PPDA） and terephthyl chloride （TPC）. The inherent viscosity (ηinh) of the polymer comes up to more than 5. This innovative agitator has the advantage of simplicity in structure and flexibility in operation, etc.

Agitator tank device and drag reduction agent evaluation

The device that consists of tank and disk agitator for evaluation drag reduction agents(DRA) was established.The effect of DRA was defined by testing the changes of agitator torque that drives the disk rotation.The HG-DRA for oil pipeline from Linyi to Puyang was studied by agitator tank device.The relationships between the drag reduction rate and Reynolds number,concentration,balance time were studied.The best concentration and the highest Renords number for the best drag reduction rate were confirmed.The results show that the drag reduction rate tested in agitator tank is close to that in pipeline.The maximum error of drag reduction rate between pipeline and agitator tank is 18.3%,which indicates that the agitator tank device is available to evaluate the effect of DRA for pipeline and it also has the advantages of simple,easy to be operated and using small volume of oil.Those are very helpful for operaters to know the properties of DRA and operate pipeline well.

Emergency department management of acute agitation in the reproductive age female and pregnancy

BACKGROUND:Agitation is a common presentation within emergent departments(EDs).Agitation during pregnancy should be treated as an obstetric emergency,as the distress may jeopardize both the patient and fetus.The safety of psychotropic medications in the reproductive age female has not been well established.This review aimed to explore a summary of general agitation recommendations with an emphasis on ED management of agitation during pregnancy.METHODS:A literature review was conducted to explore the pathophysiology of acute agitation and devise a preferred treatment plan for ED management of acute agitation in the reproductive age or pregnant female.RESULTS:While nonpharmacological management is preferred,ED visits for agitation often require medical management.Medication should be selected based on the etiology of agitation and the clinical setting to avoid major adverse effects.Adverse effects are common in pregnant females.For mild to moderate agitation in pregnancy,diphenhydramine is an effective sedating agent with minimal adverse effects.In moderate to severe agitation,high-potency typical psychotropics are preferred due to their neutral effects on hemodynamics.Haloperidol has become the most frequently utilized psychotropic for agitation during pregnancy.Second generation psychotropics are often utilized as second-line therapy,including risperidone.Benzodiazepines and ketamine have demonstrated adverse fetal outcomes.CONCLUSION:While randomized control studies cannot be ethically conducted on pregnant patients requiring sedation,animal models and epidemiologic studies have demonstrated the effects of psychotropic medication exposure in utero.As the fetal risk associated with multiple doses of psychotropic medications remains unknown,weighing the risks and benefits of each agent,while utilizing the lowest effective dose remains critical in the treatment of acute agitation within the EDs.

Numerical Simulation of the Mechanical Stirring Process in a Tannin-Based Foaming Precursor Resin

Tannin foam is a new functional material.It can be widely applied to the automobile industry,construction industry,and packaging industry due to its wide range of raw materials,renewable,easily degraded,low cost and almost no pollution.Preparing tannin foam is a very complex process that includes high temperature,two phases,mechanical agitation,and phase change.To investigate the influence of the stirring velocity and paddle shape,simulation was calculated by making use of the volume of fluid(VOF)method and multiple reference frame(MRF)method in a three-dimensional flow field of tannin-based foaming precursor resin.The gas holdup and velocity magnitude were analysed with various conditions of mechanical velocities and paddle shape in the stirring flow field.The result shows the higher the velocity,the greater the disturbance and paddle shape between the eggbeater and the Rushton turbine,obviously the paddle shape of the eggbeater with a wider range of agitation,which can entrap more air into the tannin-based foaming precursor resin in a short time.Especially when the speed is 1500 rpm,the flow field of the Rushton turbine comes out of a ditch,which decreases the efficiency of mass transfer;there is less air to mix into the tannin-based foaming precursor resin,which causes unevenness.At the same time,the eggbeater shows the marvelous capability of hybrid as it has two vortexes and multiple cycles that make a difference from the Rushton turbine,which has only one vortex and two upper and lower loops;the structure makes the flow field more stable allowed evenness of flow field tannin-based foaming precursor resin.The results reveal that it is beneficial for tannin-based foaming precursor resin to use an eggbeater with a speed of 1500 rpm to reduce the consumption of resources while obtaining a uniform flow field.

Influencing factors and risk prediction model for emergence agitation after general anesthesia for primary liver cancer

BACKGROUND General anesthesia is commonly used in the surgical management of gastrointestinal tumors;however,it can lead to emergence agitation(EA).EA is a common complication associated with general anesthesia,often characterized by behaviors,such as crying,struggling,and involuntary limb movements in patients.If treatment is delayed,there is a risk of incision cracking and bleeding,which can significantly affect surgical outcomes.Therefore,having a proper understanding of the factors influencing the occurrence of EA and implementing early preventive measures may reduce the incidence of agitation during the recovery phase from general anesthesia,which is beneficial for improving patient prognosis.AIM To analyze influencing factors and develop a risk prediction model for EA occurrence following general anesthesia for primary liver cancer.METHODS Retrospective analysis of clinical data from 200 patients who underwent hepatoma resection under general anesthesia at Wenzhou Central Hospital(January 2020 to December 2023)was conducted.Post-surgery,the Richmond Agitation-Sedation Scale was used to evaluate EA presence,noting EA incidence after general anesthesia.Patients were categorized by EA presence postoperatively,and the influencing factors were analyzed using logistic regression.A nomogram-based risk prediction model was constructed and evaluated for differentiation and fit using receiver operating characteristics and calibration curves.RESULTS EA occurred in 51(25.5%)patients.Multivariate analysis identified advanced age,American Society of Anesthesiologists(ASA)grade Ⅲ,indwelling catheter use,and postoperative pain as risk factors for EA(P<0.05).Conversely,postoperative analgesia was a protective factor against EA(P<0.05).The area under the curve of the nomogram was 0.972[95%confidence interval(CI):0.947-0.997]for the training set and 0.979(95%CI:0.951-1.000)for the test set.Hosmer-Lemeshow test showed a good fit(χ^(2)=5.483,P=0.705),and calibration curves showed agreement between predicted and actual EA incidence.CONCLUSION Age,ASA grade,catheter use,postoperative pain,and analgesia significantly influence EA occurrence.A nomogram constructed using these factors demonstrates strong predictive accuracy.

Correlation between pre-anesthesia anxiety and emergence agitation in non-small cell lung cancer surgery patients

BACKGROUND Preoperative anxiety is a common emotional problem during the perioperative period and may adversely affect postoperative recovery.Emergence agitation(EA)is a common complication of general anesthesia that may increase patient discomfort and hospital stay and may be associated with the development of postoperative complications.Pre-anesthetic anxiety may be associated with the development of EA,but studies in this area are lacking.AIM To determine the relationship between pre-anesthetic anxiety and EA after radical surgery in patients with non-small cell lung cancer(NSCLC).METHODS Eighty patients with NSCLC undergoing surgical treatment between June 2020 and June 2023 were conveniently sampled.We used the Hospital Anxiety and Depression Scale’s(HADS)anxiety subscale(HADS-A)to determine patients’anxiety at four time points(T1-T4):Patients’preoperative visit,waiting period in the surgical waiting room,after entering the operating room,and before anesthesia induction,respectively.The Riker Sedation-Agitation Scale(RSAS)examined EA after surgery.Scatter plots of HADS-A and RSAS scores assessed the correlation between patients’pre-anesthesia anxiety status and EA.We performed a partial correlation analysis of HADS-A scores with RSAS scores.RESULTS NSCLC patients’HADS-A scores gradually increased at the four time points:7.33±2.03 at T1,7.99±2.22 at T2,8.05±2.81 at T3,and 8.36±4.17 at T4.The patients’postoperative RSAS score was 4.49±1.18,and 27 patients scored≥5,indicating that 33.75%patients had EA.HADS-A scores at T3 and T4 were significantly higher in patients with EA(9.67±3.02 vs 7.23±2.31,12.56±4.10 vs 6.23±2.05,P<0.001).Scatter plots showed the highest correlation between HADS-A and RSAS scores at T3 and T4.Partial correlation analysis showed a strong positive correlation between HADS-A and RSAS scores at T3 and T4(r=0.296,0.314,P<0.01).CONCLUSION Agitation during anesthesia recovery in patients undergoing radical resection for NSCLC correlated with anxiety at the time of entering the operating room and before anesthesia induction.

Factors influencing agitation during anesthesia recovery after laparoscopic hernia repair under total inhalation combined with caudal block anesthesia

BACKGROUND Laparoscopic hernia repair is a minimally invasive surgery,but patients may experience emergence agitation(EA)during the post-anesthesia recovery period,which can increase pain and lead to complications such as wound reopening and bleeding.There is limited research on the risk factors for this agitation,and few effective tools exist to predict it.Therefore,by integrating clinical data,we have developed nomograms and random forest predictive models to help clinicians predict and potentially prevent EA.AIM To establish a risk nomogram prediction model for EA in patients undergoing laparoscopic hernia surgery under total inhalation combined with sacral block anesthesia.METHODS Based on the clinical information of 300 patients who underwent laparoscopic hernia surgery in the Nanning Tenth People’s Hospital,Guangxi,from January 2020 to June 2023,the patients were divided into two groups according to their sedation-agitation scale score,i.e.,the EA group(≥5 points)and the non-EA group(≤4 points),during anesthesia recovery.Least absolute shrinkage and selection operator regression was used to select the key features that predict EA,and incorporating them into logistic regression analysis to obtain potential pre-dictive factors and establish EA nomogram and random forest risk prediction models through R software.RESULTS Out of the 300 patients,72 had agitation during anesthesia recovery,with an incidence of 24.0%.American Society of Anesthesiologists classification,preoperative anxiety,solid food fasting time,clear liquid fasting time,indwelling catheter,and pain level upon awakening are key predictors of EA in patients undergoing laparoscopic hernia surgery with total intravenous anesthesia and caudal block anesthesia.The nomogram predicts EA with an area under the receiver operating characteristic curve(AUC)of 0.947,a sensi-tivity of 0.917,and a specificity of 0.877,whereas the random forest model has an AUC of 0.923,a sensitivity of 0.912,and a specificity of 0.877.Delong’s test shows no significant difference in AUC between the two models.Clinical decision curve analysis indicates that both models have good net benefits in predicting EA,with the nomogram effective within the threshold of 0.02 to 0.96 and the random forest model within 0.03 to 0.90.In the external model validation of 50 cases of laparoscopic hernia surgery,both models predicted EA.The nomogram model had a sensitivity of 83.33%,specificity of 86.84%,and accuracy of 86.00%,while the random forest model had a sensitivity of 75.00%,specificity of 78.95%,and accuracy of 78.00%,suggesting that the nomogram model performs better in predicting EA.CONCLUSION Independent predictors of EA in patients undergoing laparoscopic hernia repair with total intravenous anesthesia combined with caudal block include American Society of Anesthesiologists classification,preoperative anxiety,duration of solid food fasting,duration of clear liquid fasting,presence of an indwelling catheter,and pain level upon waking.The nomogram and random forest models based on these factors can help tailor clinical decisions in the future.

Comparison of Propofol and Fentanyl for Preventing Emergence Agitation Following Sevoflurane Anesthesia in Pediatric Patients: A Single-Center Study in Bangladesh

Background: Emergence agitation (EA) is a common phenomenon observed in pediatric patients following general anesthesia. This study aimed to assess the efficacy of propofol and fentanyl in preventing EA and to compare their associated complications or side effects. Methods: This prospective randomized observational comparative study was conducted at Dhaka Medical College Hospital from July 2013 to June 2014. The study aimed to evaluate the effects of propofol and fentanyl on EA in children aged 18 to 72 months undergoing circumcision, herniotomy, and polypectomy operations. Ninety children were included in the study, with 45 in each group. Patients with psychological or neurological disorders were excluded. Various parameters including age, sex, weight, American Society of Anesthesiologists (ASA) class, duration of anesthesia, Saturation of Peripheral Oxygen (SPO2), heart rate (HR), respiratory rate (RR), Pediatric Anesthesia Emergence Delirium (PAED) score, duration of post-anesthesia care unit (PACU) stay, incidence of laryngospasm, nausea, vomiting, and rescue drug requirement were compared between the two groups. Results: Age, sex, weight, ASA class, and duration of anesthesia were comparable between the two groups. Perioperative SpO2 and HR were similar in both groups. However, the PAED score was significantly higher in the fentanyl group during all follow-ups except at 30 minutes postoperatively. The mean duration of PACU stay was significantly longer in the fentanyl group. Although the incidence of laryngospasm was higher in the fentanyl group, it was not statistically significant. Conversely, nausea or vomiting was significantly higher in the fentanyl group. The requirement for rescue drugs was significantly higher in the fentanyl group compared to the propofol group. Conclusion: Both propofol and fentanyl were effective in preventing emergence agitation in pediatric patients undergoing various surgical procedures under sevoflurane anesthesia. However, propofol demonstrated a better safety profile with fewer incidences of nausea, vomiting, and rescue drug requirements compared to fentanyl.

Application of early enteral nutrition nursing based on enhanced recovery after surgery theory in patients with digestive surgery

BACKGROUND Postoperative nursing can improve the restlessness and gastrointestinal function of patients with tracheal intubation under general anesthesia in digestive surgery.Wide application of various nursing methods and routine nursing in periop-erative nursing of patients with general anesthesia in digestive surgery.AIM To investigate the impact of early postoperative enteral nutrition nursing based on the enhanced recovery after surgery(ERAS)theory on postoperative agitation and gastrointestinal recovery in patients undergoing general anesthesia that experienced tracheal intubation.METHODS The data of 126 patients with digestive surgery from May 2019 to February 2022 were retrospectively analyzed.According to different nursing methods,they were divided into control group and observation group,with 63 cases in observation group and 63 cases in control group.The patients in the control group had standard perioperative nursing care,whereas those in the observation group got enteral nourishment as soon as possible after surgery in accordance with ERAS theory.Both the rate and quality of gastrointestinal function recovery were compared between the two groups after treatment ended.Postoperative anes-thesia-related adverse events were tallied,patients'nutritional statuses were monitored,and the Riker sedation and agitation score(SAS)was used to measure the incidence of agitation.RESULTS When compared to the control group,the awake duration,spontaneous breathing recovery time,extubation time and postoperative eye-opening time were all considerably shorter(P<0.05).There was no significant difference in the recovery time of orientation force between the two groups(P>0.05);however,the observation group had a lower SAS score than the control group(P<0.05).The recovery time for normal intestinal sounds,the time it took to have the first postoperative exhaust,the time it took to have the first postoperative defecation,and the time it took to have the first postoperative half-fluid feeding were all faster in the observation group than in the control group(P<0.05);Fasting blood glucose was lower in the observation group compared to the control group(P<0.05),while the albumin and hemoglobin levels were higher on the first and third postoperative days;however,there was no statistically significant difference in the incidence of anesthesia-related adverse reactions between the two groups(P>0.05).CONCLUSION The extremely early postoperative enteral nutrition nursing based on ERAS theory can reduce the degree of agitation,improve the quality of recovery,promote the recovery of gastrointestinal function,and improve the nutritional status of patients in the recovery period after tracheal intubation under general anesthesia.

Effects of acupuncture on Alzheimer’s disease: the mechanistic study

Introduction Alzheimer’s disease(AD)is a degenerative disease of the central nervous system characterized by memory loss and cognitive impairment,often accompanied by emotional apathy,agitation,depression,delusions aggression,and other psychological symptoms[1–3].Psychological symptoms such as apathy,agitation,and depression tend to increase with the duration and severity of AD.

右美托咪定对老年患者七氟醚全麻苏醒期躁动的影响

全麻苏醒期躁动（emergence agitation,EA）是在麻醉苏醒期出现的躁动、兴奋和定向障碍等不恰当行为[1],可能对手术疗效产生极大的危害,常常造成手术切口的破裂和医疗资源配置的浪费。右美托咪定（dexmedetomidine,Dex）是α2肾上腺素能受体激动剂,可以抑制交感神经兴奋,兼具镇静和镇痛作用[2]本研究旨在评价Dex和咪达唑仑用于老年患者七氟烷全麻时对苏醒期躁动的影响,报告如下。

Kinetics of Reaction-Crystallization of Struvite in the Continuous Draft Tube Magma Type CrystallizersmInfluence of Different Internal Hydrodynamics

A laboratory-scale reaction-crystallization process of struvite synthesis from diluted water solution of Mg^2＋, NH^＋ 4 and PO3- ions was studied. The research covered the tests of two original constructions of continuous jet-pump Draft Tube Magma （DTM）-type crystallizers with internal circulation of suspension （upward/downward）. Interactions between constructional, hydrodynamic and kinetic factors were established and discussed. Nucleation and linear growth rates of struvite crystals were calculated on the basis of population density distribution. Kinetic model of idealized Mixed Suspension Mixed Product Removal （MSMPR） crystallizer considering the size-dependent growth mechanism was applied （Rojkowski hyperbolic equation）. For comparison purposes the kinetic data corre- sponded to a simpler, continuous draft tube-type crystallizer equipped with propeller agitator were analyzed. It was concluded that crystal product of larger size was withdrawn from the jet-pump DTM crystallizer of the descending flow of suspension in a mixing chamber.

Numerical Simulation of the Whole Three-Dimensional Flow in a Stirred Tank with Anisotropic Algebraic Stress Model

In accordance to the anisotropic feature of turbulent flow, ananisotropic algebraic stress model is adopted to predict theturbulent flow field and turbulent characteristics generated by aRushton disc turbine with the improved inner-outer iterativeprocedure. The predicted turbulent flow is compared with experimentaldata and the simulation by the standard k-ε turbulence model. Theanisotropic algebraic stress model is found to give better predictionthan the standard k-ε turbulence model. The predicted turbulent flowfield is in accordance to experimental data and the trend of theturbulence intensity can be effectively reflected in the simulation.

Investigation on Eccentric Agitation in the Stirred Vessel Using 3D-Laser Doppler Velocimeter

The spatial structure of the velocity field in a stirred vessel with water has been measured and analyzed using the laser Doppler velocimeter technique, with the immersing depth and agitation speed of the impeller re-maining approximately constant. The experimental results were provided such as the mean velocity field, fluctuat-ing velocities, turbulent kinetic energy, Reynolds shear stress and time series of the velocity in the stirred tank. These results probably provided the valuable basis to further optimize and enlarge the stirred tank in the industrial process.

Experimental and CFD Heat Transfer Studies of Al2Oa-Water Nanofluid in a Coiled Agitated Vessel Equipped with Propeller

This paper presents the heat transfer characteristics of A1203-water nanofluid in a coiled agitated vessel with propeller agitator. The experimental study was conducted using 0.10%, 0.20% and 0.30% volume concentra tion of A1203-water nanofluids. The results showed considerable enhancement of convective heat transfer using the nanofluids. The empirical correlations developed for Nusselt number in terms of Reynolds number, Prandtl number, viscosity ratio and volume concentration fit with the experimental data within ±10%. The heat transfer characteris tics were also simulated using computational fluid dynamics using FLUENT software with the standard ke model and multiple reference frame were adopted. The computational fluid dynamics （CFD） predicted Nusselt number agrees well with the experimental value and the discrepancy is found to be less than ＋8%.

Process Intensification in Pneumatically Agitated Slurry Reactors

Pneumatically agitated slurry reactors,including bubble column reactors and airlift loop reactors(ALRs),are important gas-liquid-solid multiphase reactors.These reactors have been widely applied in many processes,especially in the biological fermentation and energy chemical industry,due to their low shear stress,good mixing,perfect mass-/heat-transfer properties,and relatively low costs.To further improve the performance of slurry reactors(i.e.,mixing and mass/heat transfer)and to satisfy industrial require-ments(e.g.,temperature control,reduction of back-mixing,and product separation),the process intensi-fication of slurry reactors is essential.This article starts by reviewing the latest advancements in the intensification of mixing and mass/heat transfer in these two types of reactors.It then summarizes process-intensification methods for mixing and separation that allow continuous production in these slurry reactors.Process-intensification technology that integrates directional flow in an ALR with simple solid-liquid separation in a hydrocyclone is recommended for its high efficiency and low costs.This arti-cle also systematically addresses vital considerations and challenges,including flow regime discrimina-tion,gas spargers,solid particle effects,and other concerns in slurry reactors.It introduces the progress of numerical simulation using computational fluid dynamics(CFD)for the rational design of slurry reactors and discusses difficulties in modeling.Finally,it presents conclusions and perspectives on the design of industrial slurry reactors.

A METHOD OF PREPARING SPHERICAL NANO-CRYSTAL CELLULOSE WITH MIXED CRYSTALLINE FORMS OF CELLULOSE Ⅰ AND Ⅱ

A new kind of nano-crysta cellulose (NCC) prepared from natural cotton fiber has been obtained by the method ofacid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are preparedfrom natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose I and II. The preparationconditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products arealso strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, theultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gelpermeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy(TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the panicle.