Rabu, 21 Desember 2011

Basic First Aid

Universal Precautions

Professional rescuers practice universal precautions when providing medical care to victims. Universal precautions are steps used to reduce the potential for victims to infect rescuers. Practicing universal precautions requires personal protective equipment, such as gloves or eye protection.



To better protect yourself, you should make sure your first aid kit is adequately stocked with the personal protective equipment necessary to practice universal precautions.

Staying Safe

Safety is an ongoing concern that must never leave your thoughts.

There is a primal instinct in many people to dash to the rescue of those in need. Regardless of the dire circumstances of whatever terrible accident or injury you may witness, it's urgent that you keep your wits about you and stay safe.

Safety is an awareness of your surroundings and a healthy fear of unstable situations. By it's very nature, an emergency is an unstable situation. If everything were truly under control, nothing bad would've happened in the first place.

If, for example, you see a person struck by a car in a crosswalk, do not rush headlong into the street to see if they're injured. You will no doubt find yourself lying next to them after being struck by the next car barreling down the road.

In its 2010 CPR Guidelines, the American Heart Association changed the order of ABC's. ABC is still the best way to remember the beginning, so here is a new way to think of the ABC's and still follow the CPR Guidelines:

* A: Awake?
* B: Breathing?
* C: Continue Care

A: Awake?

Briskly rub the victim's breastbone with your knuckles to wake him.
Rod Brouhard



Determine if the Victim is Awake

A is for Awake. Is the victim awake, yes or no?

If our victim is not awake, try to wake him. Give him a brisk shake of the shoulders or rub your knuckles on his breastbone and shout something. Anything will work. Try "Hey you!" or "Yo, dude!" or "Go Giants!" It doesn't matter what you say, as long as you say it nice and loud to give him a chance to wake up.

Not waking up? Make sure someone is calling 911 (if no one else is there to help, then you should call 911 before you do anything else). Now, move on to B: Breathing.

If she is awake, let's talk to her. If the victim can't talk, is she choking? If she is choking, do the Heimlich Maneuver.

If the victim wants an ambulance or wants to go to the hospital, make the call. If she's talking but not making sense and she's confused, call 911 immediately and start thinking about why she might be confused.

B: Breathing?
Place hands on the breastbone between the nipples.
(c) Justin Sullivan/Getty Images


Is the Victim Breathing?

B is for Breathing. If your victim is not breathing, start CPR. Remember to tell someone to call 911 if you haven't already.

Start CPR by pushing on the middle of his chest, right between the nipples. Push hard and fast, at least 2 inches deep and at least 100 times per minute (sing Stayin' Alive or Another One Bites the Dust in your head and push with the beat).

If you've never taken a CPR class -- or you don't remember all the steps that well -- then just keep pushing fast and hard until somebody shows up to help (Hands Only CPR).

If you feel comfortable with CPR, then follow the steps: 30 chest compressions, followed by two rescue breaths, and repeat. Here are the steps to help you remember:

* Adult CPR
* Child CPR (before puberty)
* Infant CPR (under a year old)

But the Victim Is Breathing!

Think your victim is breathing? Take another look. Is he gasping for air kind of slowly, like a fish out of water? If so, start CPR just like if he wasn't breathing (how to do CPR on gasping victims).

So you've decided that your victim is breathing fairly normally. Someone called 911 when you realized your victim wasn't waking up (nobody's calling 911? Call now).

Take a breath (your victim is, so you can) and move on to C: Continue Care.

C: Continue Care
Control bleeding until the ambulance arrives.
(c) Rod Brouhard


Continue to Care for the Victim

C is to Continue Care. You have a victim who won't wake up (unconscious) but is breathing. 911 has been called and an ambulance is on the way. If the 911 operator tells you what to do, follow the operator's instructions and stop reading this.

If you're on your own, here are some tips to follow until the ambulance gets there:

* If the victim is face down and unconscious, roll her on her back, face up.
* If the victim has fluid, blood, vomit or food in his mouth, roll him on his side with his arm under his head (see the illustration).
* Stop any bleeding by putting pressure on the wound.
* If the victim stops breathing, start CPR.
* Gather the victim's medications if available and lock up any dogs they may have.

Some conditions have special considerations. Click on these to learn what to do:

* Seizures
* Low blood sugar
* Anaphylaxis
* Shortness of breath

When the Ambulance Isn't Coming

The ABC's up to this point assume that an ambulance is on the way or the hospital is not far. Sometimes, however, you're on your own for much longer. If that's the case, now's the time to treat simple injuries.

Injuries that need immediate care:

* Amputations
* Bee stings
* Bleeding
* Burns
* Head Injuries
* Snake bites

Exposure injuries (too hot or too cold) that need immediate treatment:

* Heat illness (heat exhaustion and heat stroke)
* Hypothermia

Injuries that can wait, unless you absolutely have to treat them:

* Frostbite (do not thaw unless no chance of being frozen again)
* Broken bones (only splint if you have to move the victim)

Dress wounds as needed (focus on the big stuff; little things can wait).

Sources:

Field JM, Hazinski MF, Sayre MR, Chameides L, Schexnayder SM, Hemphill R, Samson RA, Kattwinkel J, Berg RA, Bhanji F, Cave DM, Jauch EC, Kudenchuk PJ, Neumar RW, Peberdy MA, Perlman JM, Sinz E, Travers AH, Berg MD, Billi JE, Eigel B, Hickey RW, Kleinman ME, Link MS, Morrison LJ, O'Connor RE, Shuster M, Callaway CW, Cucchiara B, Ferguson JD, Rea TD, Vanden Hoek TL. "Part 1: executive summary: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care." Circulation. 2010;122(suppl 3):S640-S656.

Markenson D, Ferguson JD, Chameides L, Cassan P, Chung K-L, Epstein J, Gonzales L, Herrington RA, Pellegrino JL, Ratcliff N, Singer A. "Part 17: first aid: 2010 American Heart Association and American Red Cross Guidelines for First Aid." Circulation. 2010;122(suppl 3):S934 -S946.


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Kamis, 15 Desember 2011

ERGONOMIC

Ergonomics is concerned with the ‘fit’ between computers and their technological robots and environments. It takes account of the user's capabilities and limitations in seeking to ensure that tasks, equipment, information and the environment suit each user.




To assess the fit between a person and the used technology, ergonomists consider the job (activity) being done and the demands on the user; the equipment used (its size, shape, and how appropriate it is for the task), and the information used (how it is presented, accessed, and changed). Ergonomics draws on many disciplines in its study of humans and their environments, including anthropometry, biomechanics, mechanical engineering, industrial engineering, industrial design, kinesiology, physiology and psychology.

Typically, an ergonomist will have a BA or BS or BD in Psychology, Industrial/Mechanical Engineering or Industrial Design or Health Sciences, and usually an MA, MS or PhD in a related discipline. Many universities offer Master of Science degrees in Ergonomics, while some offer Master of Ergonomics or Master of Human Factors degrees. In the 2000s, occupational therapists have been moving into the field of ergonomics and the field has been heralded as one of the top ten emerging practice areas.[3]

According to the International Ergonomics Association within the discipline of ergonomics there exist domains of specialization:[1]

* Physical ergonomics: is concerned with human anatomy, and some of the anthropometric, physiological and bio mechanical characteristics as they relate to physical activity.
* Cognitive ergonomics: is concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system. (Relevant topics include mental workload, decision-making, skilled performance, human-computer interaction, human reliability, work stress and training as these may relate to human-system and Human-Computer Interaction design.)
* Organizational ergonomics: is concerned with the optimization of socio technical systems, including their organizational structures, policies, and processes.(Relevant topics include communication, crew resource management, work design, design of working times, teamwork, participatory design, community ergonomics, cooperative work, new work programs, virtual organizations, telework, and quality management.)

History and etymology

The foundations of the science of ergonomics appear to have been laid within the context of the culture of Ancient Greece. A good deal of evidence indicates that Greek civilization in the 5th century BC used ergonomic principles in the design of their tools, jobs, and workplaces. One outstanding example of this can be found in the description Hippocrates gave of how a surgeon's workplace should be designed and how the tools he uses should be arranged (see Marmaras, Poulakakis and Papakostopoulos, 1999).[4] It is also true that archaeological records of the early Egyptians Dynasties made tools, household equipment, among others that illustrated ergonomic principles. It is therefore questionable whether the claim by Marmaras, et al., regarding the origin of ergonomics, can be justified (I G Okorji, 2009). The term ergonomics, from Greek Έργον, meaning "work", and Νόμος, meaning "natural laws", first entered the modern lexicon when Wojciech Jastrzębowski used the word in his 1857 article Rys ergonomji czyli nauki o pracy, opartej na prawdach poczerpniętych z Nauki Przyrody (The Outline of Ergonomics, i.e. Science of Work, Based on the Truths Taken from the Natural Science).

Later, in the 19th century, Frederick Winslow Taylor pioneered the "Scientific Management" method, which proposed a way to find the optimum method for carrying out a given task. Taylor found that he could, for example, triple the amount of coal that workers were shoveling by incrementally reducing the size and weight of coal shovels until the fastest shoveling rate was reached. Frank and Lillian Gilbreth expanded Taylor's methods in the early 1900s to develop "Time and Motion Studies". They aimed to improve efficiency by eliminating unnecessary steps and actions. By applying this approach, the Gilbreths reduced the number of motions in bricklaying from 18 to 4.5, allowing bricklayers to increase their productivity from 120 to 350 bricks per hour.

World War II marked the development of new and complex machines and weaponry, and these made new demands on operators' cognition. The decision-making, attention, situational awareness and hand-eye coordination of the machine's operator became key in the success or failure of a task. It was observed that fully functional aircraft, flown by the best-trained pilots, still crashed. In 1943, Alphonse Chapanis, a lieutenant in the U.S. Army, showed that this so-called "pilot error" could be greatly reduced when more logical and differentiable controls replaced confusing designs in airplane cockpits.

In the decades since the war, ergonomics has continued to flourish and diversify. The Space Age created new human factors issues such as weightlessness and extreme g-forces. How far could environments in space be tolerated, and what effects would they have on the mind and body? The dawn of the Information Age has resulted in the new ergonomics field of human-computer interaction (HCI). Likewise, the growing demand for and competition among consumer goods and electronics has resulted in more companies including human factors in product design.

The coining of the term Ergonomics, however, is now widely attributed to British psychologist Hywel Murrell, at the 1949 meeting at the UK's Admiralty, which led to the foundation of The Ergonomics Society. He used it to encompass the studies in which he had been engaged during and after the II World War.

Applications


More than twenty technical subgroups within the Human Factors and Ergonomics Society[5] (HFES) indicate the range of applications for ergonomics. Human factors engineering continues to be successfully applied in the fields of aerospace, aging, health care, IT, product design, transportation, training, nuclear and virtual environments, among others. Kim Vicente, a University of Toronto Professor of Ergonomics, argues that the nuclear disaster in Chernobyl is attributable to plant designers not paying enough attention to human factors. "The operators were trained but the complexity of the reactor and the control panels nevertheless outstripped their ability to grasp what they were seeing [during the prelude to the disaster]."

Physical ergonomics is important in the medical field, particularly to those diagnosed with physiological ailments or disorders such as arthritis (both chronic and temporary) or carpal tunnel syndrome. Pressure that is insignificant or imperceptible to those unaffected by these disorders may be very painful, or render a device unusable, for those who are. Many ergonomically designed products are also used or recommended to treat or prevent such disorders, and to treat pressure-related chronic pain.

Human factors issues arise in simple systems and consumer products as well. Some examples include cellular telephones and other hand held devices that continue to shrink yet grow more complex (a phenomenon referred to as "creeping featurism"), millions of VCRs blinking "12:00" across the world because very few people can figure out how to program them, or alarm clocks that allow sleepy users to inadvertently turn off the alarm when they mean to hit 'snooze'. A user-centered design (UCD), also known as a systems approach or the usability engineering life cycle aims to improve the user-system.

Design of ergonomics experiments
Question book-new.svg
This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2011)

There is a specific series of steps that should be used in order to properly design an ergonomics experiment. First, one should select a problem that has practical impact. The problem should support or test a current theory. The user should select one or a few dependent variable(s) which usually measures safety, health, and/or physiological performance. Independent variable(s) should also be chosen at different levels. Normally, this involves paid participants, the existing environment, equipment, and/or software. When testing the users, one should give careful instructions describing the method or task and then get voluntary consent. The user should recognize all the possible combination's and interactions to notice the many differences that could occur. Multiple observations and trials should be conducted and compared to maximize the best results. Once completed, redesigning within and between subjects should be done to vary the data. It is often that permission is needed from the Institutional Review Board before an experiment can be done. A mathematical model should be used so that the data will be clear once the experiment is completed.

The experiment starts with a pilot test. Make sure in advance that the subjects understand the test, the equipment works, and that the test is able to be finished within the given time. When the experiment actually begins, the subjects should be paid for their work. All times and other measurements should be carefully measured and recorded. Once all the data is compiled, it should be analyzed, reduced, and formatted in the right way. A report explaining the experiment should be written. It should often display statistics including an ANOVA table, plots, and means of central tendency. A final paper should be written and edited ,after numerous drafts to ensure an adequate report is the final product.

Ergonomics in the workplace
Bilaterally symmetric operating areas of the stationary human body

Outside of the discipline itself, the term 'ergonomics' is generally used to refer to physical ergonomics as it relates to the workplace (as in for example ergonomic chairs and keyboards). Ergonomics in the workplace has to do largely with the safety of employees, both long and short-term. Ergonomics can help reduce costs by improving safety. This would decrease the money paid out in workers’ compensation. For example, over five million workers sustain overextension injuries per year. Through ergonomics, workplaces can be designed so that workers do not have to overextend themselves and the manufacturing industry could save billions in workers’ compensation.

Workplaces may either take the reactive or proactive approach when applying ergonomics practices. Reactive ergonomics is when something needs to be fixed, and corrective action is taken. Proactive ergonomics is the process of seeking areas that could be improved and fixing the issues before they become a large problem. Problems may be fixed through equipment design, task design, or environmental design. Equipment design changes the actual, physical devices used by people. Task design changes what people do with the equipment. Environmental design changes the environment in which people work, but not the physical equipment they use.

Fields of ergonomics

Engineering psychology

Engineering psychology is an interdisciplinary part of ergonomics and studies the relationships of people to machines, with the intent of improving such relationships.

Macroergonomics

Macroergonomics is an approach to ergonomics that emphasizes a broad system view of design, examining organizational environments, culture, history, and work goals. It deals with the physical design of tools and the environment. It is the study of the society/technology interface and their consequences for relationships, processes, and institutions. It also deals with the optimization of the designs of organizational and work systems through the consideration of personnel, technological, and environmental variables and their interactions. The goal of macroergonomics is a completely efficient work system at both the macro- and micro-ergonomic level which results in improved productivity, and employee satisfaction, health, safety, and commitment. It analyzes the whole system, finds how each element should be placed in the system, and considers all aspects for a fully efficient system. A misplaced element in the system can lead to total failure.

History

Macroergonomics, also known as organizational design and management factors, deals with the overall design of work systems. This domain did not begin to receive recognition as a sub-discipline of ergonomics until the beginning of the 1980s. The idea and current perspective of the discipline was the work of the U.S. Human Factors Society Select Committee on the Future of Human Factors, 1980-2000. This committee was formed to analyze trends in all aspects of life and to look at how they would impact ergonomics over the following 20 years. The developments they found include:

1. Breakthroughs in technology that would change the nature of work, such as the desktop computer,
2. The need for organizations to adapt to the expectations and needs of this more mature workforce,
3. Differences between the post-World War II generation and the older generation regarding their expectations the nature of the new workplace,
4. The inability of solely microergonomics to achieve reductions in lost-time accidents and injuries and increases in productivity,
5. Increasing workplace liability litigation based on safety design deficiencies.

These predictions have become and continue to become reality. The macroergonomic intervention in the workplace has been particularly effective in establishing a work culture that promotes and sustains performance and safety improvements.

Methods[6]

* Cognitive Walkthrough Method: This method is a usability inspection method in which the evaluators can apply user perspective to task scenarios to identify design problems. As applied to macroergonomics, evaluators are able to analyze the usability of work system designs to identify how well a work system is organized and how well the workflow is integrated.
* Kansei Method: This is a method that transforms consumer’s responses to new products into design specifications. As applied to macroergonomics, this method can translate employee’s responses to changes to a work system into design specifications.
* High Integration of Technology, Organization, and People (HITOP): This is a manual procedure done step-by-step to apply technological change to the workplace. It allows managers to be more aware of the human and organizational aspects of their technology plans, allowing them to efficiently integrate technology in these contexts.
* Top Modeler: This model helps manufacturing companies identify the organizational changes needed when new technologies are being considered for their process.
* Computer-integrated Manufacturing, Organization, and People System Design (CIMOP): This model allows for evaluating computer-integrated manufacturing, organization, and people system design based on knowledge of the system.
* Anthropotechnology: This method considers analysis and design modification of systems for the efficient transfer of technology from one culture to another.
* Systems Analysis Tool (SAT): This is a method to conduct systematic trade-off evaluations of work-system intervention alternatives.
* Macroergonomic Analysis of Structure (MAS): This method analyzes the structure of work systems according to their compatibility with unique sociotechnical aspects.
* Macroergonomic Analysis and Design (MEAD): This method assesses work-system processes by using a ten-step process.
* Virtual Manufacturing and Response Surface Methodology (VMRSM).[7]: This method uses computerized tools and statistical analysis for workstation design.

Neonatal ergonomics

Neonatal ergonomics is the field that studies the newborn's development (premature, ill, low birth weight, or healthy newborn) in his or her environment, whether in a Neonatal Intensive Care Unit or at home, and in an incubator, bed or in Kangaroo Care. This field enhances the quality of life of the baby by using ergonomics principles and best practice by providing sound physical/musculoskeletal, physiological, neurological, and psychological/social/emotional development, and decreasing life threatening events that may be caused by poor habitat/environment, such as bradycardia/apnea of prematurity.

Seating ergonomics

The best way to reduce pressure in the back is to be in a standing position. However, there are times when you need to sit. When sitting, the main part of the body weight is transferred to the seat. Some weight is also transferred to the floor, back rest, and armrests. Where the weight is transferred is the key to a good seat design. When the proper areas are not supported, sitting in a seat all day can put unwanted pressure on the back causing pain.

The lumbar (bottom five vertebrate in the spine) needs to be supported to decrease disc pressure. Providing both a seat back that inclines backwards and has a lumbar support is critical to prevent excessive low back pressures. The combination which minimizes pressure on the lower back is having a backrest inclination of 120 degrees and a lumbar support of 5 cm. The 120 degrees inclination means the angle between the seat and the backrest should be 120 degrees. The lumbar support of 5 cm means the chair backrest supports the lumbar by sticking out 5 cm in the lower back area. One drawback to creating an open body angle by moving the backrest backwards is that it takes ones body away from the tasking position, which typically involves leaning inward towards a desk or table. One solution to this problem can be found in the kneeling chair. A proper kneeling chair creates the open body angle by lowering the angle of the lower body, keeping the spine in alignment and the sitter properly positioned to task. The benefit of this position is that if one leans inward, the body angle remains 90 degrees or wider. One mis-perception regarding kneeling chairs is that the body's weight bears on the knees, and thus users with poor knees cannot use the chair. This misperception has led to a generation of kneeling chairs that attempt to correct this by providing a horizontal seating surface with an ancillary knee pad. This design wholly defeats the purpose of the chair. The Variable balans is recognized as being the original modern kneeling chair, from which all subsequent designs have been derived. Created by Peter Opsvik, in the balans, some of the weight bears on the shins, not the knees, but the primary function of the shin rests (knee rests) are to keep one from falling forward out of the chair. Most of the weight remains on the buttocks. Another way to keep the body from falling forward is with a saddle seat. This type of seat is generally seen in some sit stand stools, which seek to emulate the riding or saddle position of a horseback rider, the first "job" involving extended periods of sitting.

Another key to reducing lumbar disc pressure is the use of armrests. They help by putting the force of your body not entirely on the seat and back rest, but putting some of this pressure on the armrests. Armrest needs to be adjustable in height to assure shoulders are not overstressed.

Organizations

The International Ergonomics Association (IEA) is a federation of ergonomics and human factors societies from around the world. The mission of the IEA is to elaborate and advance ergonomics science and practice, and to improve the quality of life by expanding its scope of application and contribution to society. As of September 2008, the International Ergonomics Association has 46 federated societies and 2 affiliated societies.

The International Society of Automotive Engineers (SAE) is a professional organization for mobility engineering professionals in the aerospace, automotive, and commercial vehicle industries. The Society is a standards development organization for the engineering of powered vehicles of all kinds, including cars, trucks, boats, aircraft, and others. The Society of Automotive Engineers has established a number of standards used in the automotive industry and elsewhere. It encourages the design of vehicles in accordance with established Human Factors principles. It is one the most influential organizations with respect to Ergonomics work in Automotive design. This society regularly holds conferences which address topics spanning all aspects of Human Factors/Ergonomics.[citation needed]

In the UK the professional body for ergonomists is The Institute of Ergonomics and Human Factors and in the USA it is the Human Factors and Ergonomics Society. In Europe professional certification is managed by the Centre for Registration of European Ergonomists (CREE). In the USA the Board of Certification in Professional Ergonomics performs this function. In Canada the professional body for ergonomists is the Association of Canadian Ergonomists.

The Human Factors and Ergonomics Society (HFES) is the world's largest organization of professionals devoted to the science of human factors and ergonomics. The Society's mission is to promote the discovery and exchange of knowledge concerning the characteristics of human beings that are applicable to the design of systems and devices of all kinds.[8]

In the UK, one organisation which has a long history of the practical application of ergonomics is the Institute of Occupational Medicine (IOM). Founded by the coal industry in 1969, from the outset the IOM employed ergonomics staff to apply ergonomics principles to the design of mining machinery and environments. To this day, the IOM continues ergonomics activities, especially in the fields of musculoskeletal disorders; heat stress and the ergonomics of personal protective equipment (PPE). Like many in occupational ergonomics, the demands and requirements of an ageing UK workforce are a growing concern and interest to IOM ergonomists.

Reference:
1. ^ab International Ergonomics Association. What is Ergonomics. Website. Retrieved 6 December 2010.
2. ^ Berkeley Lab. Integrated Safety Management: Ergonomics. Website. Retrieved 9 July 2008.
3. ^ Top 10 Emerging Practice Areas To Watch in the New Millennium, article on American Occupational Therapy Association web site [sic]
4. ^ Marmaras, N., Poulakakis, G. and Papakostopoulos, V. (1999). Ergonomic design in ancient Greece. Applied Ergonomics, 30 (4), pp. 361-368.
5. ^ Technical Groups page at HFES Web site
6. ^ Brookhuis, K., Hedge, A., Hendrick, H., Salas, E., and Stanton, N. (2005). Handbook of Human Factors and Ergonomics Models. Florida: CRC Press.
7. ^ Ben-Gal et al. (2002), The Ergonomic Design of Workstation Using Rapid Prototyping and Response Surface Methodology. IIE Transactions on Design and Manufacturing, 34(4), 375-391. Available at: http://www.eng.tau.ac.il/~bengal/Ergonomics_Paper.pdf
8. ^ Human Factors and Ergonomics Society. http://www.hfes.org/

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Rabu, 30 November 2011

KEBISINGAN

1.Definisi kebisingan
Kebisingan merupakan suara atau bunyi yang secara fisis merupakan penyimpangan tekanan, pergeseran partikel dalam medium elastis seperti misalnya udara. Secara fisiologis merupakan sensasi yang timbul sebagai akibat propagasi energi getaran dari suatu sumber getar yang sampai ke gendang telinga.



Kebisingan dapat juga diartikan bentuk suara yang tidak sesuai dengan tempat dan waktunya, sehingga secara umum kebisingan dapat diartikan sebagai suara yang merugikan manusia dan lingkungan. Bising dikategorikan pada polutan lingkungan atau buangan yang tidak terlihat, tapi efeknya cukup besar. Sedangkan definisi dari bunyi sendiri merupakan bentuk gelombang longitudinal yang merambat secara perapatan dan perenggangan terbentuk oleh partikel zat perantara serta ditimbulkan oleh sumber bunyi yang mengalami getaran.

2.Sumber Bising
Sumber bising dapat dikelompokkan menjadi :
1. kebisingan industri
2. kebisingan kegiatan konstruksi
3. kebisingan kegiatan olahraga dan seni
4. kebisingan lalu lintas.

3.Pengukuran Kebisingan
Unit untuk mengukur intensitas bunyi adalah desibel (dB). Skala desibel merupakan skala yang bersifat logaritmik. Penambahan tingkat desibel berarti kenaikan tingkat kebisingan yang cukup besar. Ada beberapa macam peralatan pengukuran kebisingan, antara lain sound survey meter, sound level meter, octave band analyzer, narrow band analyzer, dan lain-lain.

4.Jenis Kebisingan


1.Bising terus menerus (continuous noise)
Bising terus menerus dihasilkan oleh mesin yang beroperasi tanpa henti.
contohnya blower, pompa, kipas angin, gergaji sirkuler, dapur pijar, dan peralatan pemprosesan (Goembira, Fadjar, Vera S Bachtiar, 2003).
Bising terus-menerus (Prabu,Putra, 2009) adalah bising dimana fluktuasi dari intensitasnya tidak lebih dari 6 dB dan tidak putus-putus.Bising kontinyu dibagi menjadi 2 (dua) yaitu:
a.Wide Spectrum adalah bising dengan spektrum frekuensi yang luas. bising ini relatif tetap dalam batas kurang dari 5 dB untuk periode 0.5 detik berturut-turut, seperti suara kipas angin, suara mesin tenun.
b.Norrow Spectrum adalah bising ini juga relatif tetap, akan tetapi hanya mempunyai frekuensi tertentu saja (frekuensi 500, 1000, 4000) misalnya gergaji sirkuler, katup gas.

Bising terputus-putus (intermittent noise)

Adalah kebisingan saat tingkat kebisingan naik dan turun dengan cepat, seperti lalu lintas dan suara kapal terbang di lapangan udara (Goembira, Fadjar, Vera S Bachtiar, 2003). Bising jenis ini sering disebut juga intermittent noise, yaitu bising yang berlangsung secara tidak terus-menerus, melainkan ada periode relatif tenang, misalnya lalu lintas, kendaraan, kapal terbang, kereta api (Prabu,Putra, 2009).

3.Bising tiba-tiba (impulsive noise)

Merupakan kebisingan dengan kejadian yang singkat dan tiba-tiba. Efek awalnya menyebabkan gangguan yang lebih besar, seperti akibat ledakan, misalnya dari mesin pemancang, pukulan, tembakan bedil atau meriam, ledakan dan dari suara tembakan senjata api (Goembira, Fadjar, Vera S Bachtiar, 2003). Bising jenis ini memiliki perubahan intensitas suara melebihi 40 dB dalam waktu sangat cepat dan biasanya mengejutkan pendengarnya seperti suara tembakan suara ledakan mercon, meriam (Prabu,Putra, 2009).

4.Bising berpola (tones in noise)

Merupakan bising yang disebabkan oleh ketidakseimbangan atau pengulangan yang ditransmisikan melalui permukaan ke udara. Pola gangguan misalnya disebabkan oleh putaran bagian mesin seperti motor, kipas, dan pompa. Pola dapat diidentifikasi secara subjektif dengan mendengarkan atau secara objektif dengan analisis frekuensi (Goembira, Fadjar, Vera S Bachtiar, 2003).

5.Bising frekuensi rendah (low frequency noise)
Bising ini memiliki energi akustik yang penting dalam range frekuensi 8-100 Hz. Bising jenis ini biasanya dihasilkan oleh mesin diesel besar di kereta api, kapal dan pabrik, dimana bising jenis ini sukar ditutupi dan menyebar dengan mudah ke segala arah dan dapat didengar sejauh bermil-mil (Goembira, Fadjar, Vera S Bachtiar, 2003).

6.Bising impulsif berulang

Merupakan kebisingan dengan kejadian yang singkat dan tiba-tiba. Efek awalnya menyebabkan gangguan yang lebih besar, seperti akibat ledakan, misalnya dari mesin pemancang, pukulan, tembakan bedil atau meriam, ledakan dan dari suara tembakan senjata api (Goembira, Fadjar, Vera S Bachtiar, 2003). Bising jenis ini memiliki perubahan intensitas suara melebihi 40 dB dalam waktu sangat cepat dan biasanya mengejutkan pendengarnya seperti suara tembakan suara ledakan mercon, meriam. Akan tetapi bising ini terjadi berulang-ulang, misalnya mesin tempa (Prabu,Putra, 2009).

Berdasarkan pengaruhnya pada manusia, bising dapat dibagi atas (Prabu,Putra, 2009):
1. Bising yang mengganggu (Irritating noise).
Merupakan bising yang mempunyai intensitas tidak terlalu keras, misalnya mendengkur.
2. Bising yang menutupi (Masking noise)
Merupakan bunyi yang menutupi pendengaran yang jelas, secara tidak langsung bunyi ini akan membahayakan kesehatan dan keselamatan tenaga kerja , karena teriakan atau isyarat tanda bahaya tenggelam dalam bising dari sumber lain.
3. Bising yang merusak (Damaging/Injurious noise)
Merupakan bunyi yang intensitasnya melampui nilai ambang batas. Bunyi jenis ini akan merusak atau menurunkan fungsi pendengaran.

Pengendalian kebisingan


Pengontrolan kebisingan pada sumber dapat dilakukan dengan modifikasi sumber, yaitu penggantian komponen atau mendisain ulang alat atau mesin supaya kebisingan yang ditimbulkan bisa dikurangi. Misalnya mengurangi faktor gesekan dan kebocoran suara, memperkecil dan mengisolasi elemen getar, melengkapi peredam pada mesin, serta pemeliharaan rutin terhadap mesin. Tetapi cara ini memerlukan penelitian intensif dan umumnya juga butuh biaya yang sangat tinggi (Goembira, Fadjar, Vera S Bachtiar, 2003).

Pengendalian kebisingan juga dapat dilakukan dengan pengendalian pada medium perambatan. Hal ini bertujuan untuk menghalangi perambatan suara dari sumber suara yang menuju ke telinga manusia. Untuk menghalangi perambatan, ditempatkanlah sound barrier antara sumber suara dan telingan. Pemblokiran rambatan ini hanya akan berhasil jika sound barrier tidak ikut bergetar (resonansi) saat tertimpa gelombang yang merambat, hal ini sangat tergantung pada bahan dimensi.
Salah satu usaha untuk mereduksi kebisingan pada daerah permukiman, dilakukan dengan Green Barrier yaitu membatasi daerah sumber kebisingan dengan daerah pemukiman masyarakat. Selain itu dapat dilakukan dengan memasang dinding pemisah antara sumber-sumber bising dengan ruangan tempat kerja (kedap suara).

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Selasa, 15 November 2011

MIKROBIOLOGI

Apa itu Mikrobiologi?
Mikrobiologi tersusun dari 3 kata, yaitu micros (kecil, renik), bios (hidup) dan logos (ilmu, pengetahuan).
Jadi mikrobiologi adalah ilmu pengetahuan yang mempelajari dan menelaah mikroba (organisme hidup yang berukuran kecil yang tidak dapat dilihat dengan mata telanjang secara langsung).



Apa Urgensi Mikrobiologi?
Mikrobiologi penting sekali dan terkait erat dengan kehidupan manusia, karena mikroba (jasad renik) tersebar merata di seluruh belahan bumi dan ada di mana-mana. Mikroba ada di udara, ada di air, di tanah, lantai, meja, kulit dan dimanapun. Oleh karena itu mikroba memiliki korelasi yang erat dan peranan yang penting dengan kehidupan manusia, yang dapat memberikan pengaruh merugikan maupun menguntungkan.

Apa Peranan Mikroba dalam kehidupan manusia?
Mikroba memiliki peranan yang yang sangat penting dalam kehidupan manusia, ada yang menguntungkan dan ada yang merugikan.

Diantara peranan mikroba yang merugikan adalah :
-Penyebab penyakit, baik pada manusia, hewan maupun tumbuhan.
-Penyebab kebusukan makanan (spoilage).
-Penyebab keracunan makanan (food borne disease).
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Diantara peranan mikroba yang menguntungkan adalah :
-Agen pembusuk alami, yang akan mendekomposisi sampah-sampah organik menjadi materi inorganik sehingga dapat mengurangi kuantitas sampah, menyuburkan tanah dan dapat menjadi sumber nutrisi bagi tumbuhan.
-Agen pembusuk di dalam saluran pencernaan alami, yang turut membantu mencerna makanan di dalam saluran pencernaan.
-Agen pengikat nitrogen dari udara yang dapat digunakan sebagai bahan nutrien bagi tumbuhan.
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Apa Peranan Ilmu Mikrobiologi?
Seiring dengan semakin majunya perkembangan ilmu mikrobiologi, maka penerapan mikrobiologi semakin meluas pada hampir semua bagian bidang. Diantaranya :
-Pada Industri Pertanian : mikrobiologi berperan penting di dalam mencegah penyakit tanaman, membantu proses penyuburan tanah, dan lain lain.
-Pada Industri Makanan : mikrobiologi berperan di dalam proses pengawetan makanan, fermentasi makanan, dan lain lain.
-Pada Industri Medis/Kesehatan : mikrobiologi sangat berperan penting di dalam antibiotik, antiseptis, kemoterapi, vaksinasi, dan lain sebagainya.
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PENGENDALIAN MIKROORGANISME
Pengendalian mikroorganisme sangat esensial dan penting di dalam industri dan produksi pangan, obat-obatan, kosmetika dan lainnya. Alasan utama pengendalian organisme adalah :
1) Mencegah penyebaran penyakit dan infeksi.
2) Membasmi mikroorganisme pada inang yang terinfeksi
3) Mencegah pembusukan dan perusakan bahan oleh mikroorganisme.

Mikroorganisme dapat dikendalikan dengan beberapa cara, dapat dengan diminimalisir, dihambat dan dibunuh dengan sarana atau proses fisika atau bahan kimia.
Ada beberapa cara untuk mengendalikan jumlah populasi mikroorganisme, diantaranya adalah sebagai berikut :
a)- Cleaning (kebersihan) dan Sanitasi
Cleaning dan Sanitasi sangat penting di dalam mengurangi jumlah populasi mikroorganisme pada suatu ruang/tempat. Prinsip cleaning dan sanitasi adalah menciptakan lingkungan yang tidak dapat menyediakan sumber nutrisi bagi pertumbuhan mikroba sekaligus membunuh sebagian besar populasi mikroba.

b)Desinfeksi
Adalah proses pengaplikasian bahan kimia (desinfektans) terhadap peralatan, lantai, dinding atau lainnya untuk membunuh sel vegetatif mikrobial. Desinfeksi diaplikasikan pada benda dan hanya berguna untuk membunuh sel vegetatif saja, tidak mampu membunuh spora.

c) Antiseptis
Merupakan aplikasi senyawa kimia yang bersifat antiseptis terhadap tubuh untuk melawan infeksi atau mencegah pertumbuhan mikroorganisme dengan cara menghancurkan atau menghambat aktivitas mikroba.

d) Sterilisasi
Proses menghancurkan semua jenis kehidupan sehingga menjadi steril. Sterilisasi seringkali dilakukan dengan pengaplikasian udara panas. Ada dua metode yang sering digunakan, yaitu :
1) Panas lembab dengan uap jenuh bertekanan. Sangat efektif untuk sterilisasi karena menyediakan suhu jauh di atas titik didih, proses cepat, daya tembus kuat dan kelembaban sangat tinggi sehingga mempermudah koagulasi protein sel-sel mikroba yang menyebabkan sel hancur. Suhu efektifnya adalah 121oC pada tekanan 5 kg/cm2 dengan waktu standar 15 menit. Alat yang digunakan : pressure cooker, autoklaf (autoclave) dan retort.
2) Panas kering, biasanya digunakan untuk mensterilisasi alat-alat laboratorium. Suhu efektifnya adalah 160oC selama 2 jam. Alat yang digunakan pada umumnya adalah oven.

e)- Pengendalian Mikroba dengan Suhu Panas lainnya
1.Pasteurisasi : Proses pembunuhan mikroba patogen dengan suhu terkendali berdasarkan  waktu kematian termal bagi tipe patogen yang paling resisten untuk dibasmi. Dalam proses pasteurisasi yang terbunuh hanyalah bakteri patogen dan bakteri penyebab kebusukan namun tidak pada bakteri lainnya. Pasteurisasi biasanya dilakukan untuk susu, rum, anggur dan makanan asam lainnya. Suhu pemanasan adalah 65oC selama 30 menit.
2.Tyndalisasi : Pemanasan yang dilakukan biasanya pada makanan dan minuman kaleng. Tyndalisasi dapat membunuh sel vegetatif sekaligus spora mikroba tanpa merusak zat-zat yang terkandung di dalam makanan dan minuman yang diproses. Suhu pemanasan adalah 65oC selama 30 menit dalam waktu tiga hari berturut-turut.
3.Boiling : Pemanasan dengan cara merebus bahan yang akan disterilkan pada suhu 100oC selama 10-15 menit. Boiling dapat membunuh sel vegetatif bakteri yang patogen maupun non patogen. Namun spora dan beberapa virus masih dapat hidup. Biasanya dilakukan  pada alat-alat kedokteran gigi, alat suntik, pipet, dll.
4.Red heating : Pemanasan langsung di atas api bunsen burner (pembakar spiritus) sampai berpijar merah. Biasanya digunakan untuk mensterilkan alat yang sederhana seperti jarum ose.
5.Flaming : Pembakaran langsung alat-alat laboratorium  diatas pembakar bunsen  dengan alkohol atau spiritus tanpa terjadinya pemijaran.
6.Pengendalian Mikroba dengan Radiasi

Bakteri terutama bentuk sel vegetatifnya dapat terbunuh dengan penyinaran sinar ultraviolet (UV) dan sinar-sinar ionisasi.

*)Sinar UV : Bakteri yang berada di udara atau yang berada di lapisan permukaan suatu benda yang terpapar sinar UV akan mati.

*)Sinar Ionisasi : yang termasuk sinar ionisasi adalah sinar X, sinar
alfa, sinar beta dan sinar gamma. Sterilisasi dengan sinar ionisasi memerlukan biaya yang besar dan biasanya hanya digunakan pada industri farmasi maupun industri kedokteran.
- Sinar X : Daya penetrasi baik namun perlu energi besar.
- Sinar alfa : Memiliki sifat bakterisidal tetapi tidak memiliki daya penetrasi.
- Sinar beta : Daya penetrasinya sedikit lebih besar daripada sinar X.
- Sinar gamma : Kekuatan radiasinya besar dan efektif untuk sterilisasi bahan makanan.
7.Pengendalian Mikroba dengan Filtrasi
Ada dua filter, yaitu filter bakteriologis dan filter udara.
- Filter bakteriologis biasanya digunakan untuk mensterilkan bahan-bahan yang tidak tahan terhadap pemanasan, misalnya larutan gula, serum, antibiotika, antitoksin, dll. Teknik filtrasi prinsipnya menggunakan penyaringan, dimana yang tersaring hanyalah bakteri saja. Diantara jenis filter bakteri yang umum digunakan adalah : Berkefeld (dari fosil diatomae), Chamberland (dari porselen), Seitz (dari asbes) dan seluosa.
- Filter udara berefisiensi tinggi untuk menyaring udara berisikan partikel (High Efficiency Particulate Air Filter atau HEPA) memungkinkan dialirkannya udara bersih ke dalam ruang tertutup dengan sistem aliran udara laminar (Laminar Air Flow)
8.Pengendalian Mikroba dengan Bahan Kimia
Saat ini, telah banyak agen kimia yang berpotensi untuk membunuh atau menghambat mikroba. Penelitian dan penemuan senyawa kimia baru terus berkembang. Agen kimia yang baik adalah yang memiliki kemampuan membunuh mikroba secara cepat dengan dosis yang rendah tanpa merusak bahan atau alat yang didisinfeksi.

Pada prinsipnya, cara kerja agen kimia ini digolongkan menjadi :

a)Agen kimia yang merusak membran sel mikroba.
1.Golongan Surfaktans (Surface Active Agents), yaitu golongan anionik, kationik dan nonionik.
2.Golongan fenol.

b)Agen kimia yang merusak enzim mikroba.
1.Golongan logam berat seperti arsen, perak, merkuri, dll.
2.Golongan oksidator seperti golongan halogen, peroksida hidrogen dan formaldehid.

c) Agen Kimia yang menyebabkan denaturasi protein
Agen kimiawi yang menyebabkan terjadinya koagulasi dan presipitasi protoplasma, seperti alkohol, gliserol dan bahan-bahan asam dan alkalis.

Ada beberapa faktor yang mempengaruhi efektivitas agen kimia di dalam mengendalikan mikroba, yaitu :
a)Konsentrasi agen kimia yang digunakan. Semakin tinggi konsentrasinya maka efektivitasnya semakin meningkat.
b)Waktu kontak. Semakin lama bahan tersebut kontak dengan bahan yang disterilkan maka hasilnya akan semakin baik.
c)Sifat dan jenis mikroba. Mikroba yang berkapsul dan berspora lebih resisten dibandingkan yang berkapsul dan berspora.
d)Adanya bahan organik dan ekstra. Adanya bahan-bahan organik dapat menurunkan efektivitas agen kimia.
e)pH atau derajat keasaman. Efektivitas bahan kimia dapat berubah  seiring dengan perubahan pH.

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