The Rate Of Aggregation, Differential, Sedimentation, And Orthokinetic Aggregation Mechanism

In this experiment we observed carmine powder to better understand the concept of Brownian motion and the role of molecular movement in diffusion. The particles continuously moved in a completely random fashion, and the smaller particles moved with more speed than the larger particles.

The purpose of this experiment was to see if a penny could hold more drops of salt water or tap water. It was found that a penny could hold an average of 22.3 drops of tap water and only 20.8 drops of salt water. These results are consistent with the hypothesis: If the salt concentration of water impacts the amount of water a penny holds, then the penny will hold less drops with salt water. While dropping the water onto the penny, it was observed that the water formed into a dome-like shape on the penny. It looked like the individual drops of water turned into one large drop of water. This was observed for both the tap and salt water. This happened due to the cohesion and surface tension of water. Cohesion simply means that water molecules are attracted to each other and want to cling together. Surface tension is the special term that is applied to the cohesion of water molecules.

Because of the small size, the particles float on the surface of water and often travel long distances during rainstorms. When there are too many of these sediments, the water

The kinetic energy causes the particles to vibrate and move randomly – moving around the area in which they are held. The random movement causes the particles to distribute randomly around the area. The higher concentrated solution has more particles that can move across the membrane compared to the lower, producing a net movement down the concentration gradient.

Nanocrystals are made up of drug with only little amount of surfactant (below critical micelle concentration (CMC)) to stabilize formulation [14]. Most of the nanoparticles are made up of large amount of excipients which is not the case with nanocrystals as most of the part is only the drug. Besides lower amount of stabilizers makes toxicity issues associated with nanosuspensions negligible and offers ease of scale-up and better physical stability compared to amorphous form [15, 16]. Different methods are classified as top-down (high pressure homogenization, media milling, and sonication) and bottom-up techniques (nanoprecipitation) for effective production of Nanocrystals [17]. Development of nanocrystal based formulation of risperidone can be advantageous to tackle the problem of poor water solubility. Numerous solidification techniques are used to increase physical stability of nanosuspensions as spray drying, lyophilization and many more based upon the properties of drug and characteristics of final formulation. Amongst all these techniques lyophilization is used predominantly for nanosuspension solidification.

Among other approaches tried by scientists, colloidal systems like liposomes, polymeric nanoparticles etc., have shown promise but not many products have made it to the market (7). Nanoparticulate drug delivery systems are gaining much popularity in recent years. Among these, nanoparticulate drug delivery systems from biodegradable and biocompatible polymer are an interesting option for controlled drug delivery and drug targeting (8). Amongst the various drug-delivery systems, solid lipid nanoparticle (SLN) and nanostructured lipid carrier (NLCs) are potentially attractive choices due to their natural components and easily scaled-up formulation processes. In addition, their hydrophobic core provides a suitable environment for entrapment of hydrophobic drugs (9). Among the important technological advantages of nanoparticles as drug carriers are: high stability (i.e. long shelf life), high carrier capacity (i.e. many drug molecules can be incorporated into the particle matrix), feasibility of incorporation of both hydrophilic and hydrophobic substances, and feasibility of variable routes of administration (10). NLCs are kind of lipid-based nanoparticles, which has the advantages of biodegradable, brain targeting, well-recognized safety profile by drastically reducing drug-related toxicities through reduction of nonspecific biodistribution (11). NLCs consist of an unstructured solid lipid

The purpose of this lab is to see how different solutions have different rates of diffusion and how surface area plays a role in

The purpose of this experiment is to observe the nett movement of particles from regions of high concentration to low concentration.

When the surfactant concentration exceeds the critical micelle concentration (cmc) in water, micelles are formed as aggregates of surfactant molecules. [6]

On lab 3 “What does ‘random’ motion look like? Describing diffusion and random motion”, we were able to see the random motion of various beads suspended in fluids of varying viscosity. We also identified how the motion of the beads differ based on bead size, bead mass, and the fluid viscosity. Furthermore, the impact of the parameters on the diffusion were studied. Based on their diffusion the random motion of the various beads was analyzed. Overall, even if there were many errors while doing the experiment we were able to know what random motion look like and it was possible to see the relationship between the parameters and the diffusion of the beads. To reduce the amount of errors occurring during doing the experiment

These become widely dispersed faster than contaminants transported in solution. Smaller particles can carry more contaminants per unit mass, as a greater surface area allows for more contaminants to adsorb onto the surface (Eisma and Irion, 1993). **************

Practical C3 RATE OF DIFFUSION Ian Curtis ABSTRACT: The rate of diffusion has always been much more efficient for smaller entities. In this practical report a practical that was conducted that uses cubes of agar and phenolphthalein is explained and the results are discussed. The definition of diffusion is as stated: the intermingling of substances by the natural movement of their particles.

Coagulation and flocculation processes are essential in a number of diverse disciplines including biochemistry, rubber manufacturing and in water and wastewater treatment (Bratby, 2006). These processes are typically used in destabilizing, agglomerating and subsequent removal of particles. Coagulation is a physico-chemical process which neutralizes the colloidal particles in water by a chemical called coagulant. The neutralization forces the colloidal particles to join together to form small aggregates called flocs which are easily filtered from the water.

“The prefix ‘nano’ stems from the ancient Greek word for ‘dwarf’. In science, it means one billionth (10 to the minus 9) of something, thus a nanometer (nm) is one billionth of a meter, or 0.000000001 meters. A nanometer is about three to five atoms wide, or some 40,000 times smaller than the thickness of human hair. A virus is typically 100 nm in size.” (Paddock) “The ability to manipulate structures and properties at the nanoscale in medicine is like having a sub-microscopic lab bench on which you can handle cell components, viruses or pieces of DNA, using a range of tiny tools, robots and tubes.” (Paddock) There is one type of microscope in the world that has the ability to see things at the nano scale. That microscope is a scanning tunneling microscope. It has the ability to zoom in on an object by 1,000,000 times as the average high school and college microscope only reaches 100(Nano.gov).

If one of the liquids wets solid particles more than the other one, the better wetting liquid becomes the continuous phase and the other becomes the dispersed phase. O/W emulsions will come into being if the three-phase contact angle θ (angle at the three-phase boundary of solid particles, continuous phase and dispersed phase) is less than 90° (e.g., silica, clay), and W/O emulsions should form if θ > 90° (e.g., carbon black). However, only when θ is relatively close to 90° can the particle effectively act as a Pickering stabilizer. The particles tend to remain dispersed in either phase if they are too hydrophilic (low θ) or too hydrophobic (high