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junior college 2 | H2 Maths
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Chowder
Chowder

junior college 2 chevron_right H2 Maths

I got 2690 when i interpolate

Date Posted: 2 months ago
Views: 20
Liu Rijing
Liu Rijing
2 months ago
Could it be the two of you used different steam tables? Please post me the steam table you used
Chowder
Chowder
2 months ago
I alr post the steam tables at the answer section

See 4 Answers

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Chowder
Chowder's answer
10 answers (A Helpful Person)
1st
This is the steam table i used
Liu Rijing
Liu Rijing
2 months ago
Bro which two set of data you used to interpolate?
Chowder
Chowder
2 months ago
hg . 111.4 and 100 degrees C
Chowder
Chowder
2 months ago
Bro u there
Liu Rijing
Liu Rijing
2 months ago
Hi sorry I was busy. From my understanding superheated steam is above its bubble point at the same pressure. By Gibbs phase rule, you have two variables you can vary independently for superheated steam. I would say you need to find two sets of data from the steam table at 1.013 bars( atmospheric pressure) 100 degree C and another date set at 1.013 bars, higher than 110 degree C.
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Liu Rijing
Liu Rijing's answer
37 answers (A Helpful Person)
Take saturated steam at 1.01325 bars 100 degree C, hg and hg at 1.01325 bars at 150 degree C superheated steam and interpolate them to 110 deg C, should get the answer.
Chowder
Chowder
2 months ago
Bro i did that too but i still didnt get the ans leh . I didnt get 2696 . I get 2690 still
Liu Rijing
Liu Rijing
2 months ago
Maybe your teacher answer is based on a different steam table, anyway the answer is close enough, dun have to sweat over the small difference
Chowder
Chowder
2 months ago
Ok thank you
Chowder
Chowder
1 month ago
Bro help . Give 2 suggestions on how to improve the heat transfer rate and explain clearly . How leh this question 4marks . Help me pls
Chowder
Chowder
1 month ago
And give one example for evaporation and drying process
Liu Rijing
Liu Rijing
1 month ago
Generally you can just increase the surface area, or increasing the velocity of cooling fluid
Chowder
Chowder
1 month ago
Can give reason like for the thing u stated for the explanation part
Chowder
Chowder
1 month ago
And what is one example for drying and evaporation process . Pls helpnme
Liu Rijing
Liu Rijing
1 month ago
Increasing surface area of the system allows more heat to be transferred out, increasing cooling fluid flow removes heat faster, increases heat transfer coefficient. For evaporation, you can increase the surface area of the liquid to be evaporated and use a fan. For drying, you can increase the exposed surface of the material and use a hot air drier to blow over it
Chowder
Chowder
1 month ago
Bro u there ?
Chowder
Chowder
1 month ago
Bro help me please exam tomoro leh help pls liao . For fluidization

if mass of the catalyst particles increases , what will be the effect on the type of fluidization ?

if mass of the catalyst particles decreases , what will be the effect on the type of fluidization ?
Chowder
Chowder
1 month ago
Bro pls help me leh
Liu Rijing
Liu Rijing
1 month ago
Heavier particles will mean you need a higher flow rate to achieve fluidization of the particles. The opposite for a lower particle weights

The weight of the particles = buoyancy of the air flow, is the condition of fluidization.

What do you mean by fluidization type
Chowder
Chowder
1 month ago
Aggregative or particulative fluidization i think? I dont know leh sorry but pls help me . How to ans this question eh
Liu Rijing
Liu Rijing
1 month ago
It is a bit hard to help, because I dun understand the qn
Chowder
Chowder
1 month ago
I send you the full question here and if you are free can you help me . And dont delete this app cos i need your help sometimes .
Liu Rijing
Liu Rijing
1 month ago
Ok
Chowder
Chowder
1 month ago
I post alr at H2 math JC2
Chowder
Chowder
1 month ago
Pls help me cos tomoro exam . Sorry and thanks
Liu Rijing
Liu Rijing
1 month ago
Ok
Liu Rijing
Liu Rijing
1 month ago
Din see it
Chowder
Chowder
1 month ago
Have leh . Its under #H2math #JC2 #Singapore ?
Liu Rijing
Liu Rijing
1 month ago
Din see it
Chowder
Chowder
1 month ago
Have leh why u keep saying u dont see sia . If u go to the unanswered post u will see mine. Pls liao leh
Liu Rijing
Liu Rijing
1 month ago
When you posted it
Chowder
Chowder
1 month ago
2 hours ago . I even said part d) . How come i can see it posted liao leh :/ .
Liu Rijing
Liu Rijing
1 month ago
Really fun see, maybe you repost ba
Chowder
Chowder
1 month ago
Nvm i post it on the ans key alr leh . U click the post at the one we are talking here then u can see the ans section . Help me de :/
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Chowder
Chowder's answer
10 answers (A Helpful Person)
Help leh
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Liu Rijing
Liu Rijing's answer
37 answers (A Helpful Person)
With increase particle mass, density increases, and hence Vmf speed increases, hence fluidization will not happen
Chowder
Chowder
1 month ago
But if decrease particle size . Density decrease . What will happen to the type of fluidization ? Btw if vmf increase it means fluidization wont happen? help me understand
Liu Rijing
Liu Rijing
1 month ago
If decrease particle size, density increases. Yes if vmf increases, fluidization cannot occur at a lower same velocity
Chowder
Chowder
1 month ago
But if its the opp how do i say fluidization will occur ? Cos the question ask me to explain what happen to the type of fludization


But i thought vmf increase good for the fluidization?

Sorry and help me please thank you
Chowder
Chowder
1 month ago
Bro u there
Liu Rijing
Liu Rijing
1 month ago
Vmf is the minimum fluidization speed for the particles, so if the speed increases the particle needs higher fluid flow speed to reach fluidization. So increasing mass will increase fluidization speed for the particles.
Chowder
Chowder
1 month ago
Means the higher the vmf the more unlikely the particles will reach fluidization? Is this true? Pls help cos i want to get good grade
Chowder
Chowder
1 month ago
And what do you mean fluidization cannot occur at same velocity . I dont understand help pls
Chowder
Chowder
1 month ago
Bro u there
Chowder
Chowder
1 month ago
Pls help
Liu Rijing
Liu Rijing
1 month ago
There is a minimum fluid flow speed that the particles need to achieve fluidization. In fluidization the particles are suspended by the upward flow of fluid like air, and the fluid needs to have a minimum speed so the particles can be suspended.
Liu Rijing
Liu Rijing
1 month ago
The fluidization speed depends on the particle density, the fluid density, the particle diameter and the void fraction of the bed, so changing either one of them the speed will change.
Chowder
Chowder
1 month ago
Bro the Q said why some winter countries use double window . Then i say cos the thicker the wall or material the higher the resistance tk heat transfer . Is this right
Liu Rijing
Liu Rijing
1 month ago
Yes you are right
Chowder
Chowder
1 month ago
Thank you so much
Chowder
Chowder
1 month ago
Bro can help
Liu Rijing
Liu Rijing
1 month ago
On?
Chowder
Chowder
1 month ago
Differential Research Project. Like research stuffs
Liu Rijing
Liu Rijing
1 month ago
OK, can share the topics
Chowder
Chowder
1 month ago
Chemical Testing- Analysis of organochlorine pesticides in herb- The project is to analyse the 
organochlorine pesticides in herb 
product by gas chromatography‐ mass 
spectrometry

Can tell me what i have to research on? My senior told me to research on
1)Performance characteristic on method validation
2)what is method validation and development
Why its important
3)development of methods thar are used to detect organochlorine pesticides from the old days to now

Is thar the only thing i have to research? No right ?
Liu Rijing
Liu Rijing
1 month ago
I think that is about it. You may want to include the comparison of different analytical methods, what kind of organochlorine pesticides are there, any general method to analyse this pesticide group...And identification methods for the different organochlorine pesticides
Chowder
Chowder
1 month ago
Ok i will add that too . Thank you . Whem im done . Can u help check my work please?
Liu Rijing
Liu Rijing
1 month ago
Ok
Chowder
Chowder
1 month ago
Hi can u check for me my research . Its not completed yet. Cos i havent added the one u suggested to me. So can u check for me tisnfirst thanks
Chowder
Chowder
1 month ago
3.Development of methods that are used to detect organochlorine

Pesticide residue analysis in food samples have evolved steadily in the last 40 years. In 1963 , the first method to develop for the detection of organochlorine was produced. Acetonitrile was used as the extraction solvent and its partitioning with petroleum ether was used for sample clean up .

As the requirements for method increases throughout the years ,the analytical range also expanded to include organophosphorus and organonitrogen pesticides. Two chemist , Becker and Luke realized that the non-polar solvents (acetonitrile and petroleum ether) used in previous method causes a partial loss of the more polar pesticides. They decided to switched the initial extraction solvent from acetonitrile to acetone.

This result in the analytical range to be expanded . However, non-polar solvents such as methylene chloride or petroleum ether were still used for partitioning. Salts such as NaCl, were added during the partitioning steps to enhance the recoveries of polar analytes.

These methods continue to be used, as detection limit becomes lower. Recent development and improvement in analytical instrumentation make this possible.

In 1993, the original ‘Luke’ Method was modified and is now referred to as Luke II Method . This method introduced solid-phase extraction (SPE) clean up set ups in both pre- and post-partitioning step. Other combination of appropriate detection technique include; GC/MS(Gas Chromatography/Mass Spectrometry) , GC/ECD(Gas Chromatography/Electron Capture Detector) , GC/NPD(Nitrogen-Phosphorous detector). These detection techniques proved that methods could be reduced to approximately 10ppb (parts per billion) for an incurred pesticide sample. Water was used as an integral part of the initial extraction to facilitate SPE loading.

However, the sample preparation procedures for this method were complicated and tedious, taking as long as 1.5days. It requires a large amount of solvent, lengthy evaporation steps and extensive use of glassware.

In 1990, many new extraction techniques were produced. They are MAE (microwave-assisted extraction, ASE (accelerated solvent extraction) and SFE (supercritical fluid extraction). Although they have individual advantages, these techniques were not widely accepted due to various practical limitations . For instance, ASE require significant numbers of preparative steps and a higher maintenance cost.

To enhance the efficiency of traditional methods, a new sample preparation approach known as QuEChERS was introduced by Anastassiades. The anagram for ‘QuEChERS’ is Quick-Easy-Cheap-Effective-Rugged-Safe.

This approach requires a single extraction in acetonitrile and require a very small sample size (10-15g). Large excess of salts and buffers are added. Excess salts are used to aid in the extraction of polar and non-polar pesticides whereas buffers are used to improve analyte stability and extract quality. This initial step simultaneously extracts the pesticides from the sample , preparing it for dispersive solid-phase extraction (d-SPE) step. The d-SPE step helps to remove residual water and further removal of matrix interferences from the sample.

All in all, QuEChERS are developed due to the 40 years of evolution of all type of methods and techniques.The QuEChERS method has become the most popular method to detect pesticides such as organochlorine. Due to its ability to allow more samples to be screened for a large quantity of compounds in a shorter period of time compared to the other previous methods, this technique is rapidly gaining acceptance across the globe .



2. What is method development and validation ? Why is it important ?

Analytical method development and validation are the continuous and inter-dependent task associated with the research and development, quality control and quality assurance departments. Analytical procedures play a critical role in equivalence and risk assessment management. It helps in formation of product-specific acceptance criteria and stability of results.Validation shows that the analytical procedure is suitable for its intented purpose.

Designing of experiment is a powerful tool for the method characterization and validation. Analytical professionals should be capable of using it to characterize and optimize the analytical method. Effective analytical method development and its validation can deliver significant improvements in precision and a reduction in bias errors. It can further help to avoid costly and time consuming exercises.

Analytical method development uses advanced technologies to determine the compositions of a formulation by analytical techniques. It is the process of proving that an analytical method is acceptable for use in laboratory to measure the concentration of subsequent samples. Analytical instruments play a major role in this process to achieve high quality and reliable analytical data. Thus, everyone in the analytical laboratory should be aware about the quality assurance of the equipments.

Analytical method could be spectral, chromatographic, electrochemical, hyphenated or miscellaneous. It should be used within GMP(Good Manufacturing Practice) and GLP (Good Laboratory Practice) environments and must be developed using the protocols and acceptance criteria set out in the ICH guidelines.

An analytical procedure is developed to test a defined characteristic of the substance against the acceptance criteria for that particular characteristic. In the development of a new analytical procedure, the choice of analytical instrumentation and methodology should be based on the intended purpose and scope of the analytical method.

The important parameters that may be assessed during method development are :specificity, linearity, LOD(limits of detection) and LOQ (quantitation limits), range, accuracy and precision During early stages of method development, the robustness of methods should be evaluated because this characteristic helps to determine which method will be approved . Analytical procedures development are primarily based on a combination of mechanistic understanding of the basic methodology and prior experiences. Experimental data from early procedures can be used to guide further development.

The ability to present accurate, reliable and consistent data is the motive of the analytical chemist. Method development procedures are complex, extended and expensive endeavours. An analytical method details the steps and techniques necessary to perform an analysis. This may include: preparation of samples, standards and reagents; use of apparatus; generation of the calibration curve, use of the formulae for the calculation

The need of validation of the analytical method development emerged due to international competition, maintaining the standard of products in high commercial & market value and ethical reasons. Various International Regulatory Agencies have set the standard and fixed the protocol to match the reference for granting approval, authentication and registration.

Data quality is assured by the combination of four components: analytical instrument qualification (AIQ); analytical method validation; system suitability tests and quality control checks. Validation of an analytical method is intended to demonstrate that it is suitable for its intended use.

The type of method and analytical technique used will control the nature and extent of the validation studies required. The most common methods for validation are identification, assay and impurities determination.

The validation of an analytic method demonstrates the scientific soundness of the measurement or characterization. It is required for various extents throughout the regulatory submission process. The validation practice shows that an analytic method measures the correct substance, in the correct amount and in the appropriate range for the samples. It enables the analyst to understand the behavior of the method and to establish the performance limits of the method.

In order to carry out method validation, the laboratory should follow a written standard operating procedure (SOP) that describes the process to conduct it. The laboratory should use qualified and calibrated instrumentation. There should be a well developed ,documented test method and an approved protocol prior to validation. The protocol is a methodical plan that describes which method performance parameters should be tested, how the parameters will be evaluated with its acceptance criteria. Below are the parameters that may be assessed during method validation.

In conclusion , method development and validation are important as they are critical elements of pharmaceutical development hence it is important to develop efficient and accurately validated analytical methods to provide safe and effective drugs for human consumption. Hence, rapid and accurate quantification of the substrate and drug product is important in the process development.

1.Performance characteristic on method validation

Method validation (MV) is sometimes referred to as the process of providing documented evidence about what a method is intended to do. Laboratories in the pharmaceutical and other regulated industries must perform MV to comply with regulations.

In MV, several performance characteristics may be investigated, depending on the type of method and its intended use. These are summarized below.

1)Accuracy is the closeness of agreement between the values found. The value accepted as a conventional true value or the accepted reference value. Several methods of determining accuracy are available:

1) It can be screened by the use of an analytical procedure to an analyte of known purity,2) by comparison of the results of the proposed analytical procedure with those of a second accepted procedure, 3)the accuracy of which is stated and defined. It can also be deduced once precision, linearity and specificity have been established.

2)Precision of an analytical procedure expresses the closeness of agreement between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions. It can be further branched into a)repeatability, b)intermediate precision and c)reproducibility. The standard deviation, relative standard deviation like coefficient of variation and confidence interval should be reported for each type of precision investigated.

a) Repeatability should be assessed using a minimum of 9 determinations covering the specified range for the procedure by 3 replicates or 6 determinations at 100% of the test concentration.

b)Immediate precision depends on the circumstances under which the procedure is intended to be used. For example, the specific day, analyst performing and equipment used are the random events that cast effect on the precision of the analytical procedure.

c)Reproducibility is assessed by means of an inter-laboratory trial. Reproducibility should be considered in case of the standardization of an analytical procedure.

3) Specificity is the ability to assess the analyte for the presence of various components that may be present. It can be established by a number of approaches, depending on the intended purpose of the method. The ability of the method to assess the analyte of interest in a drug product is determined by a check for interference by placebo. Lack of specificity of an individual analytical procedure may be compensated by other supporting analytical procedures.

4) The quantitation limit of an individual analytical procedure can be understood as the smallest amount of analyte in a sample that can be determined quantitatively with appropriate precision and accuracy. Used primarily to determine impurities and/or degrades in products this is a parameter of quantitative assays for estimating the low levels of compounds in sample matrices

4) The detection limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value..

6. The linearity of an analytical procedure is its ability to obtain test results that are directly proportional to the concentration of analyte in the sample.

7. The range of an analytical procedure is the interval between the upper and lower concentration of analyte in the sample for which it has been demonstrated that the analytical procedure has a suitable level of precision, accuracy and linearity.

8. Robustness is typically assessed by the effect of small changes in chromatographic methods on system suitability parameters such as peak retention, resolution and efficiency.
Liu Rijing
Liu Rijing
1 month ago
This is ok
Chowder
Chowder
1 month ago
Serious leh . U read alr ?