... Figure 4.21 shows the magnetic hysteresis loop of CoFe2-xZnxO4 powders at room temperature, with a maximum applied field of up to 8 kOe. The saturated magnetization, remanence and coercivity are summarized in Table 4.10. Also, Figure 4.22 presented variations of saturated magnetization and coercivities for CoFe2-xZnxO4 powders as a function of compositions calcined at 900 ºC for 48 h. The magnetization value of doped samples increased sharply with the external magnetic field strength at the low field region. The highest saturated magnetization can be obtained in x = 0.1 Zn doped cobalt ferrites. Increasing in saturated magnetization can be attributed to influence of the cationic stoichiometry and its occupancy in specific sites. The magnetic order in the cubic system of ferromagnetic spinels was due to occurrence of the super-exchange interaction mechanism between metal ions in the tetrahedral A-site and octahedral B-site [20]. When the nonmagnetic zinc ion was substituted by the cobalt ferrite lattice, due to the zinc ferrite being a normal spinel, it had a stronger preference for the tetrahedral site and thus reduced the amount of Fe3+ in the A site. The net result, due to antiferromagnetic coupling, was an increase in magnetic moment on the B lattice and an increase in saturated magnetization. However, at high levels of zinc substitution in x > 0.1, the A-site magnetic ion becomes so diluted that coupling between the two lattices was lost, and the saturated magnetization drops...
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...Nevertheless, the specific saturation magnetization is reduced due to a dead magnetic layer at the surface of the particles [3] if the temperature and the time of annealing are decreased. In the case of strontium ferrites, the influence of a strontium excess on the crystallografic structure is the same. The lattice occupation is not perturbed if an excess of strontium according to n = 5.25 is used. For a larger amount of strontium in the starting xerogel, the intermediate phase SrFe03., can be separated by etching with HC1. Nevertheless, in the range n = 5.25 6.0, the influence of the surplus on the static magnetic properties is typically different compared to intrinsic barium hexaferrites. Here, the specific saturation magnetization of the powders annealed at 950°C for 5h does not depend on the ratio n, whereas HCM decreases from 480 kA/m for n = 6.0 to 400 kA/m in the case of n = 5.25. This decrease of the coercive field strength for n < 6.0 can be avoided by reducing the annealing temperature to 850°C. According to the irreversible part of the FMR-spectra in figure 2 (right) showing no shift of the high field resonance peak with decreasing annealing temperature, the effective anisotropy field strength of the samples is not influenced, whereas the transition from incoherent to coherent magnetization reversal, indicated by the height of the low field resonance peak, by reducing the annealing temperature is obvious. If the annealing time is decreased, the coercive...
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...Broadly, hydrogen selection membranes (based on the materials used) can be categorized into four types: (i) polymer (organic), (ii) metallic, (iii) carbon, and (iv) ceramic.8 The latter three are called inorganic membranes. Inorganic membranes can be classified into two groups from the viewpoint of the raw material-metal membranes and ceramic membranes.21 Also, it could be divided into porous (meso- and microporous) and nonporous (dense) membranes.25 Dense inorganic membranes are typically made of a polycrystalline ceramic or metal. The table below illustrates some of the most important factors in membrane properties. [pic] [pic] Table 15 provides a comparison of the classes of the H2 separation membrane materials presented throughout this review. When this information is compared against the 2015 targets, we quickly see that each individual class has its own distinct advantages and disadvantages While polymer-based membranes are arguably the cheapest and easiest processed of the materials, they are less thermally robust and lack sufficient selectivity and flux capacities. Dense type polymer membranes can be divided into glassy and rubbery polymeric membranes. The former have higher selectivity and lower flux, whereas the latter have higher flux but lower selectivity.19 According to Kluiters,19 operating temperatures for polymer membranes are _100 °C. Several key advantages are that they possess the ability to cope with high-pressure drops and low cost. However,...
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...Richard Ching Biology 141 Exam 1 Study Questions 1-15 1. What is the difference between an hypothesis and a scientific Theory? Between an hypothesis and a prediction? What kinds of hypotheses are useful for scientific investigations that try to explain the natural world, and which are not? Give one or more examples of hypotheses that are and are not scientifically useful. A scientific theory is an explanation for a broad class of phenomena or observations, whereas a hypothesis is a testable statement to explain the workings of a particular scientific theory. In other words, a hypothesis aims to find out how a phenomena occurs. What distinguishes a hypothesis from a prediction is that a prediction is simply a part of a hypothesis, and is an observable or measureable result that must hold true if the hypothesis is correct. A hypothesis is useful to a scientific investigation in the case that it can be tested and have results gathered from experimentation or observation, while hypotheses that cannot be tested and concluded upon are not useful. An example of a useful hypothesis is the question of whether or not cramming increases test performance when compared to consistent studying, and an example of a hypothesis that is not scientifically useful would be the question of whether God truly exists. 2. Two of the greatest unifying ideas in biology (i.e., concepts that account for and are consistent with a very large number of observations) are the Cell Theory, and the Theory...
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...Effects of Temperature on Membrane Permeability on Beta vulgaris Abstract In this experiment, we studied the effect of temperature on the cell membrane of a common garden beet Beta vulgaris. Beet roots were washed thoroughly, cut into six cylinders and then placed in separate test tubes. We placed each test tube in separate water baths at different temperatures for a specific period of time. The test tubes were then removed from the water baths and the absorbance of the solutions containing betalain pigments was recorded using a spectrophotometer . Maximum absorbance was recorded at -8°C (followed by the absorbance at 78.9 °C) indicating maximum release of pigments from the cell while minimum absorbance was recorded at 8°C. The results of the experiment were mostly consistent with the expectations and it was found that with increase in temperature the absorbance increases and so does the release of pigments from the cell. Introduction Cell is the basic structural and functional unit of life . The word cell comes from the Latin word ‘cella’ , meaning small room. Cell was first discovered by Robert Hooke as a descriptive term for the smallest living biological creature. The cell theory, developed by Schleiden and Schwann states that all cells arise from pre- existing cells by cell division , each cell acts as an elementary organism and all organisms are composed of one or more cells. On the basis of number of cells organisms can be classified as unicellular...
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...Challenges within a CMO Purification Process A Case Study of Crossflow Micro- and Ultrafiltration 6th European Downstream Technology Forum September 7, 2010, Sartorius College, Goettingen Agenda I. II. Introduction Overview applications for CFF at RHB III. Case study I & II IV. Strategies to maintain quality Richter-Helm offers services for (co-)development and manufacture of biopharmaceuticals Business Units and Services In- & Out-Licensing Marketing & Sales Contract development Contract manufacturing Business Development Team GMP-Production Facility, Bovenau 3 Richter-Helm was one of the first companies to produce recombinant proteins in accordance to GMP-guidelines History of Richter-Helm Timeline 1987 1989 1993 1998 2000 2001 Foundation of Pharma Biotechnologie Hannover and start of GMP production Entering contract GMP manufacturing Broadening service portfolio / establishment of contract development services Building up of development centre in Hamburg Planning and start of construction of the new large scale GMP facility in Bovenau First long-term commercial development and supply agreement for large scale facility signed Initiation of GMP production in Bovenau Acquisition by Gedeon Richter Plc and HELM AG Start of in-house development projects Fully remodelled Hannover facility in operation Capacity enlargement in Bovenau More than 20 years of experience in biopharmaceuticals production 3 development and production locations 2003...
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...Contact lenses General Purpose: To demonstrate how to put in contact lenses safely. Specific Purpose: At the end of my speech, the audience should be able to safely put in contacts. Central Statement: Knowing how to put your own contacts in safely. Introduction I. Original opening: Many people have eye problems from children to adults, but most wear glasses because they are unsure how to use contact lenses. II. Qualifying statement: I myself have visual problems when I was in the 4th grade I was teased a lot for having to wear glasses; so when I became old enough to buy my first pair of contacts I was ecstatic and needed to learn how to put them in on my own. III. Statement relating topic to audience: (same as Qualifying statement) IV. Preview statement: I have been wearing contacts for a little over 20 years and now I see that contacts are coming more into styles. Body I. Things you need before you get started. a. Contact lenses b. Clean hands II. How to put in contact lenses. c. Wash your hands with soap. d. Remove one contact from its case. e. Place the contact on the index finger you’re most comfortable with using. f. Gently pull your skin away from your eye. g. Move the contact towards your eye calmly and steadily. h. Gently place the contact on your eye. i. Let go of the skin around your eye. j. Blink slowly so as to not dislodge the contact. k. Repeat the process with...
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...Cell membranes are a selectively permeable phospholipid layer that act as a barrier between the internal and external environments of the cell (Singer and Nicolson 1972). Osmosis is the movement of solvent across a semipermeable membrane from low solute to high solute concentration; osmolarity is the concentration of an osmotic solution. Tonicity describes the relative concentrations of two solutions to determine movement of diffusion of solute across the membrane separating the solutions. The permeability of the rabbit red blood cell membrane is explored, factors varying the degrees of permeability to different solutes, and the effects on the cell from this movement of solutes and water across the membrane. The resultant effects when rabbit red blood cells are introduced to solutions of varying tonicity – isotonic, hypotonic, and hypertonic – are also observed. The permeability of the cell membrane to various organic solutes based on factors like molecular weights and lipid-water partition coefficients is also studied. The permeability of a cell membrane to a solute does not appear to show a high dependence on the molecular weight of said solute (Finkelstein 1976). The lipid-water partition coefficient, on the other hand, does affect the ease and speed at which molecules cross the cell membrane. It is a measure of the solubility difference of a particular solute between the two immiscible phases of lipid and water; a coefficient equal to less than 1 means a greater amount...
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...(ex: cells dividing uncontrollably.. cancer) - You are made of 75 trillion cells Cells divided into: - Sex cells: sperms/eggs - Somatic cells: cells of the body Looking at the structure of a cell can show the cell’s function Environment of the cell - Cytoplasm (intracellular fluid) - Cytoplasm (intracellular fluid - Extracellular fluid: usually fluid like, consists of resources Acts as a cellular freeway.. allows movement of medium across the cell 1) Usually watery fluid 2) It is the matrix of connective tissues 3) Little intercellular space in some tissues (control substances around the cell) 4) Provides nutrients, gases, wastes (bring in hormones 5) May be blood of lymph within specific vessels - Plasma Membrane (separation of membranes) Controls what comes in and out of the cell 1) Surrounds every cell 2)...
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...AP Biology Summer Independent Study Packet Directions: As you carefully read through chapters 1-7 in your Campbell Biology textbook, thoughtfully respond to each of the following questions. It is important that you actually read the chapters for review and understanding. Do not just look for answers to the questions provided. Review all diagrams provided. The majority of the material in these beginning chapters should be a review for you. If need be, focus on those areas which may seem less familiar. After reviewing this material independently during the summer, it is expected that you have a solid understanding of these basic concepts for the start of this course. Prepare any specific questions that you may have. Again, this is an independent review and you will be expected to know these concepts for future use and assessment. This introductory material will not be covered in detail during class time. Chapter 1: Introduction: Themes in the Study of Life 1. Explain the importance of a biological hierarchy in terms of biological organization. 2. Why must scientists study the interactions of organisms with each other and the environment? 3. Comment on the relationship between structure and function in biology. 4. How specifically is the cell life’s basic unit of structure and function? 5. What is the significance of DNA to organisms? 6. Explain the basic concept of a biological feedback system. How does it work? 7. Explain briefly...
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...Biology 141, Fall 2012 Exam 1 Study Questions (rev. 083112) The questions on the first hour exam will be based on those given below. Questions on the exam will be in multiple choice form, but if you can answer the questions here, you will have no trouble with the exam. [Notes: 1. These questions are meant to provoke thought and study. Do not ask the instructors or the TAs to provide you with the answers. 2. Crossed out study questions will not be use as the basis for exam questions.] 1. What is the difference between an hypothesis and a scientific Theory? Between an hypothesis and a prediction? What kinds of hypotheses are useful for scientific investigations that try to explain the natural world, and which are not? Give one or more examples of hypotheses that are and are not scientifically useful. 2. Two of the greatest unifying ideas in biology (i.e., concepts that account for and are consistent with a very large number of observations) are the Cell Theory, and the Theory of Evolution by Natural Selection. Most scientific Theories have two components: the pattern component and the process component. What are the two components of Cell Theory and of the Theory of Evolution by Natural Selection? What are the two conditions required by the process component of evolutionary theory? 3. What is the hypothesis of Spontaneous Generation and how does Cell Theory challenge that hypothesis? In the Pasteur experiment two types of flasks were used. For each flask, what...
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...Organelle membranes and the plasma membrane are selectively permeable, allowing water to freely pass through but regulating the movement of solutes. The cell actively moves some dissolved substances across membranes, expending adenosine triphosphate (ATP) (biological energy) to accomplish the movement. Other substances move passively, without expenditure of ATP from the cell, but only if the cell membrane is permeable to those substances. Water and selected solutes move passively through the cell and cell membranes by diffusion, a physical process in which molecules move from an area where they are in high concentration to one where their concentration is lower. The energy driving diffusion comes only from the intrinsic kinetic energy in all atoms and molecules. If nothing hinders the movement, a solute will diffuse until it reaches equilibrium. EXERCISE 1. Diffusion of Molecules Through a Selectively Permeable Membrane Materials string or rubber band 500 – mL beaker one-third filled water sharpie handheld test tube holder 30 % glucose solution 3 standard test tubes starch solution disposable transfer pipettes I2KI solution 2 400 – mL beakers to hold dialysis bag Benedict’s reagent 30 – cm strip of moist dialysis tubing hot plate Introduction Dialysis tubing is a membrane made of regenerated cellulose fibers formed into a flat tube. If two solutions containing dissolved substances of different molecular weights are separated by this membrane, some substances...
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...Please do not plagiarize. Only use these study questions for study purposes, and to check your own work. Answers are NOT guaranteed to be correct. Biology 141, Spring 2012 Exam 1 Study Questions The questions on the first hour exam will be based on those given below. Questions on the exam will be in multiple choice form, but if you can answer the questions here, you will have no trouble with the exam. [Notes: 1. These questions are meant to provoke thought and study. Do not ask the instructors or the TAs to provide you with the answers. 2. Crossed out study questions will not be use as the basis for exam questions.] 1. What is the difference between a hypothesis and a scientific Theory? Between a hypothesis and a prediction? What kinds of hypotheses are useful for scientific investigations that try to explain the natural world, and which are not? Give one or more examples of hypotheses that are and are not scientifically useful. The difference between a hypothesis and a scientific theory is that a hypothesis is a proposed ‘theory’ and a scientific theory is theories that explain and predict any observable occurrence therefor the scientific theory is testing the hypothesis. The difference between a hypothesis and a prediction is that a hypothesis is used as an explanation to theory, and is proposed at the beginning of an experiment, while a prediction is the result of an experiment based on the hypothesis that is being tested. The kind of hypotheses’ that are...
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...Laboratory 2: Neurosim: Membrane potentials and Action potentials INTRODUCTION NeuroSim is a computer program intended for use in teaching neurophysiology, specifically the concepts associated with the resting membrane potential and the action potential. Within the NeuroSim program is a simulation entitled HH which is based on the equations developed by English physiologists A. L. Hodgkin and A. F. Huxley (J. Physiol. Lond. 117: 500-‐542, 1952). Much of our current knowledge about the mechanisms of resting membrane potentials and action potentials comes from experiments performed by Hodgkin and Huxley on a giant nerve fiber found in the squid species Loligo forbesi (adult squid weight 3.5 lb, adult squid length 14 in). Because of the large diameter of their axons (up to 0.8 mm), it became a convenient model for elecrophysiological research using small intracellular microelectrodes (tip diameter < 0.5 μm). With two microelectrodes, researchers were able to detect an electrical potential difference between...
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...Movement Part A: demonstrating differential permeability Part B: A model for osmosis Aim: To observe and record the effects a differentially permeable membrane has on the process of diffusion. To observe and examine the process of osmosis. Partner: Phil Reichelt Results: Part A demonstrating differential permeability Table 1 results of test: | Water in tube at start of experiment (distilled water) | Water in tube at start of experiment (distilled water) | Water in tube at end of experiment | Water in tube at end of experiment | | clinistix | Iodine test | clinistix | Iodine test | Results | Glucose not present in deionised water | Starch not present deionised water | Glucose present in external deionised water | No evidence of starch being present | interpretation | The water is not contaminated | The water is not contaminated | Glucose has diffused through the membrane | No change | Part B results shown on the following page Discussion: PART A – 3) a. The two substances present in the dialysis bag at the start of the experiment were glucose and starch. In the solution outside the dialysis bag, we later found the presence of glucose, indicating it had moved from the inside of the dialysis bag into the external deionised water. The reasons for glucose being able to penetrate the membrane is because glucose is a monosaccharide molecule (simple sugars) and a small enough to pass through the pores of the membrane ( dialysis bag). b. The difference between...
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