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2.2 Principle of direct torque control of induction motor:
In a direct torque controlled induction motor drive, it is possible to control directly the stator flux linkage (s?) or the rotor flux (r?)or the magnetizing flux (m?) and the electromagnetic torque by the selection of an optimal inverter voltage vector. The selection of the voltage vector of the voltage source inverter is made to restrict the flux and torque error within their respective flux and torque hysteresis bands and to get the fastest torque response and highest efficiency at every instant. DTC enables both quick torque response in the transient operation and reduction of the harmonic losses and acoustic noise.
The Benefits of using DTC include the following:
1 No need for motor speed or position feedback in 95% of applications. Thus, installation of costly encoders or other feedback devices can be avoided.
2DTC control is available for different types of motor including permanent magnet and synchronous reluctance motors.
3Accurate torque and speed control down to low speeds, as well as full startup torque down to zero speed.
4 Excellent torque linearity.
5 High static and dynamic speed accuracy.
6 No preset switching frequency optimal transistor switching is determined
2.2.1 Voltage Source Inverter
A six step voltage source inverter provides the variable frequency AC voltage input to the induction motor in DTC method. The DC supply to the inverter is provided either by a DC source like a battery, or a rectifier supplied from a three phase or single phase AC source. Fig. 2.2 shows a six step voltage source inverter. The inductor L is inserted to limit short circuit through fault current. A large electrolytic capacitor C is inserted to stiffen the DC link voltage.
The switching devices in the voltage source inverter bridge must be capable of being turned OFF and ON. Insulated gate bipolar transistors (IGBT) are used because they can offer high switching speed with enough power rating. Each IGBT has an inverse parallel-connected diode. This diode provide alternate path for the motor current after the IGBT, is turned off.

Figure 2.2 Voltage Source Inverter
Each leg of the inverter has two switches one connected to the high side (+) of the DC link and the other to the low side (-); only one of the two can be ON at any moment. When the high side gate signal is ON the phase is assigned the binary number 1, and assigned the binary number 0 when the low side gate signal is ON. Considering the combinations of status of phases a, b and c the inverter has eight switching modes(Va,Vb,Vc=000-111) V2 (000) are zero voltage vectors V0 (000) and V7 (111) where the motor terminals are short circuited and the others are nonzero voltage vectors V1 to V6
The six nonzero voltages space vectors will have the orientation, and also shows the possible dynamic locus of the stator flux, and its different variation depending on the VSI states chosen. The possible global locus is divided into six different sectors signaled by the discontinuous line. Each vector lies in the center of a sector of width named S1 to S6 according to the voltage vector it contains.
It can be seen that the inverter voltage directly force the stator flux, the required stator flux locus will be obtained by choosing the appropriate inverter switching state. Thus the stator flux linkage move in space in the direction of the stator voltage space vector at a speed that is proportional to the magnitude of the stator voltage space vector. By selecting one after another the appropriate stator voltage vector, is then possible to change the stator flux in the required method. If an increase of the torque is required then the torque is controlled by applying voltage vectors that advance the
same sector depending on the stator flux position.

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2.2.2. Concept
The concept of Industry 4.0 can be summed up in 3 words: Economy, Personalization and Accessibility.
The factory, in this concept, must be digitized through the use of the Internet of Things to ensure a regular diagnosis and this can only cause the optimization of the machines performance.
Also, the factory of the future must be flexible especially after the connection of the machine with the outside world. The final costumer must have the right to choose the product and the modifications he wishes.
Another concept of Industry 4.0 is to be able to simulate the factory by models called virtual or digital twins. This twin will be used to put a reference for a machine to know the factors of optimal operation.
And finally, and more importantly, the Manufactory must be energy efficient as well as in raw materials. And this is the great challenge of this revolution

2.2.3. Technologies
To ensure the industry of the future to be smart and be able part of the industrial concept 4.0, we will require the presence of many different and important parts:

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Standardization
The machines must be connected to each other and to facilitate this, it was necessary to create a common protocol between it. This Protocol is the OPC UA.
Also, to properly implement this model, it was necessary to create standards such as IEC62264 (Enterprise-Control Systems Integration) and IEC61512 (Design and Specification of Batch Manufacturing Process Control Systems) and currently the Standard IEC62890 is in the finalization phase.

Network infrastructure
In this context, communication plays a very important role. In order to upgrade the factories, the infrastructure must first be changed.
WIFI, Zig Bee, Lora, all are wireless communication protocols. Each has its advantages and disadvantages. For example Bluetooth is faster but less energy efficient in comparison to the Zig Bee.

Augmented Reality
It’s a new technology that is based on the progress of mobile devices. It consists of superimposing elements (3D, 2D, Sounds …) on reality.
It is now used everywhere considering the ease of transmission of information.
In the industrial field, one of these applications can be used to equip an operator with a virtual reality glasses and guide him to execute his task or sent commands in real time.
Big Data and Cloud Computing
The communication of the machines will generate the circulation of enormous data.
These data can reflect the global state of the industry that is why it was necessary to set up analysis and data management systems in order to gain in quality, speed and especially in economy.
One of the Solutions that has emerged, these data analysis systems can appear on CLOUD platforms. This technology makes it possible to centralize information and increase connectivity between the different parts of the factory.

The Cobots
This is the second generation of robots. They are collaborative robots equipped with several sensors to ensure the safety of the human being. His role is to assist the operator.
3. Universal Robot
Previously we have indicated that the cobots play an important role in the phase of transition to the new era, they are the future of the automation industry.

3.1. UR general presentation
UR’s particular reduced weight and their hyper intuitive programming have made it easier and possible to robotize the production from the very small series as they are easily transportable also their speed of implementation allows us to use them at various and different production stations.
3.1.1. UR and Industry
UR presents a simple and smart solution to every industry’s challenges. We can use it to automate different and variety of industries: Food and Agriculture, Furniture and Equipment, Electronics and Technology, Metal and Machine, Automotive and Subcontractors, Plastics and Polymers, Pharmacy and Chemistry, Scientific and Research.
Also, it allows us to virtually automate different applications such as assembly, painting, screw-driving, labelling, packing, polishing, injection molding, welding…
3.1.2. Origin and History
The following table 2.1 gathers general information about the universal robot creation.

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2.6 GENOME PLASTICITY AND EVOLUTION OF ESCHERICHIA COLI
Like all life forms, new strains of E. coli evolve through the natural biological processes of mutation, gene duplication, and horizontal gene transfer; in particular, 18% of the genome of the laboratory strain MG1655 was horizontally acquired since the divergence from Salmonella. E. coli K-12 and E. coli B strains are the most frequently used varieties for laboratory purposes. Some strains develop traits that can be harmful to a host animal. These virulent strains typically cause a bout of diarrhea that is often self-limiting in healthy adults but is frequently lethal to children in the developing world. (Futadar et al., 2005). More virulent strains, such as O157:H7, cause serious illness or death in the elderly, the very young, or the immunocompromised.
The genera Escherichia and Salmonella diverged around 102 million years ago (credibility interval: 57–176 mya), which coincides with the divergence of their hosts: the former being found in mammals and the latter in birds and reptiles. (Wang et al., 2009). This was followed by a split of an Escherichia ancestor into five species (E. albertii, E. coli, E. fergusonii, E. hermannii, and E. vulneris). The last E. coli ancestor split between 20 and 30 million years ago.
The long-term evolution experiments using E. coli, begun by Richard Lenski in 1988, have allowed direct observation of genome evolution over more than 65,000 generations in the laboratory. For instance, E. coli typically do not have the ability to grow aerobically with citrate as a carbon source, which is used as a diagnostic criterion with which to differentiate E. coli from other, closely, related bacteria such as Salmonella. In this experiment, one population of E. coli unexpectedly evolved the ability to aerobically metabolize citrate, a major evolutionary shift with some hallmarks of microbial speciation.
2.7 INCUBATION PERIOD
The time between ingesting the STEC bacteria and feeling sick is called the “incubation period”. The incubation period is usually 3–4 days after the exposure, but may be as short as 1 day or as long as 10 days. The symptoms often begin slowly with mild belly pain or non-bloody diarrhea that worsens over several days. HUS, if it occurs, develops an average of 7 days after the first symptoms, when the diarrhea is improving.

2.7.1 DISCOVERY OF ANTIBIOTICS
• History of antibiotics – 1
19th century:Louis Pasteur & Robert Koch
• History of antibiotics – 2
Plant extracts
– Quinine (against malaria)
– Ipecacuanha root (emetic, e.g. in dysentery)
Toxic metals
– Mercury (against syphilis)
– Arsenic (Atoxyl, against Trypanosoma)
• Dyes
– Trypan Blue (Ehrlich)
– Prontosil (azo-dye, Domagk, 1936)
• History of antibiotics – 3
Paul Ehrlich
• started science of chemotherapy
• Systematic chemical modifications
(“Magic Bullet”) no. 606 compound = Salvarsan (1910)
• Selective toxicity.
• Developed the Chemotherapeutic Index
• History of antibiotics – 4
Penicillin- the first antibiotic – 1928• Alexander Fleming observed the
killing of staphylococci by a fungus (Penicillium notatum)
• observed by others – never exploited
• Florey & Chain purified it by freeze-drying (1940) – Nobel prize 1945
• First used in a patient: 1942
• World War II: penicillin saved 12-15% of lives
• History of antibiotics – 5
Selman Waksman – Streptomycin (1943), was the first scientist who discovered antibiotic active against all Gram-negatives for examples; Mycobacterium tuberculosis
– Most severe infections were caused by Gram-negatives and Mycobacterium
tuberculosis, extracted from Streptomyces – extracted from Streptomyces
– 20 other antibiotics include. neomycin, actinomycin
2.8 CHARACTERISTICS OF ANTIBIOTICS
According to the Oxford Dictionary, the term Antibiotics encompasses medicines (such as penicillin or its derivatives) that inhibit the growth of or destroys microorganisms. Antibiotics are naturally occurring substances that exhibit inhibitory properties towards microbial growth at high concentrations. (Zaffiri, et al., 2012).
-Antibiotics are selective in their effect on different microorganisms, being specific in their action not only against genera and species but even against strains and individual cells. Some of these agents act mainly on gram-positive bacteria, while others inhibit only gram-negative ones.
-Some antibiotics are produced by some organism, from different strains of penicillin.
-Bacteria are sensitive to the antibiotic which enable them to developed resistance after contact, for several periods.

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2.9 ROLE OF ANTIBIOTICS
Based on the clinical use of antibiotics, it may appear that these compounds play a similar role as microbial weapons in nature, yet this seems unlikely due to the fact that the concentrations used in the clinical setting are significantly higher than that produced in nature (Fajardo et al., 2008). Due to experimental evidence, it makes more sense to see antibiotics as small, secreted molecules involved in cell-to-cell communication within microbial communities.
(Martinez, 2008). Diverse Studies have been conducted in which different antibiotics and antibiotic-like structures were administered to different bacterial species at levels below the compounds minimum inhibitory concentrations (MIC). (Fajardo et al., 2008). that was

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2. Brabeck-Letmathe emphasizes the need for incremental approach to change. Do you agree that this what he has done? Discuss the differences and similarities between his view and your view of what has occurred at Nestle, both historically and in recent times.
Yes, I agree with what Brabeck-Letmathe has conducted an incremental approach to change. Simply incremental change must happen slowly and steadily because it is such a continuous changes which help the organization to improve their productivity as well. If they make all changes happen at once instead of over a period of time, then there will be no incremental change in term of their production and it would be a transformational changes which is happen in one time only. He expanded Nestle with different products, which I think it could helped them to increase their production. He also tried to improve their strengths and make them better from time to time. I believe that he could have done this better financially because having too many investors can put a financial burden on the organization.
On the other hand, if the change in Nestle happened at blast, the results would not been as good for such a huge organization like Nestle. Nestle went through a variety of acquisitions in different countries over the past 100 years. The first priority for Nestle is to work on improving the alignment between these various acquisitions. Next, Nestle should focus on the strength of the new acquisitions and look for an ongoing improvement for them. Nestle also belt and sustained its strength gradually for a long period of time, and has been establishing its core value over the course of decades. Therefore, the incremental approach to change was so essential for a well-known company like Nestle to maintain its strength, core values and success rather than changing it entirely.
However, he is despite the complete overhaul of the executive director by replacing it with 10 new executives, which can be an effective and important symbol of commitment to change. The restructuring that he done is continual process at Nestle that focus on developing the strengths of the organization, our team believe that if the organization is doing well, no radical changes need to be implement. Brabeck-Letmathe willing to take the risk of finance to implement restructuring because he believe with replacing it with 10 new executives will develop the strengths of Nestle. Brabeck-Letmathe did the merge and acquisitions by being major shareholder in the cosmetic giant L’Oreal. He also purchased pharmaceutical and ophthalmic by purchased Alcon Laboratories Inc. which is Nestle is a worldwide leader known for manufacturing products. From our view, mergers and acquisitions enable organizational growth at accelerated rates and they continue to be popular or well-known, although with seasonal variations. Mergers and acquisitions also can excessive capacity and consolidate operations in more mature industries.

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