Spot Welding

Spot welding is a resistance welding method used to join two to four overlapping metal sheets which are up to 3 mm thick each. In some applications with only two overlapping metal sheets, the sheet thickness can be up to 6 mm. Two copper electrodes are simultaneously used to clamp the metal sheets together and to pass current through the sheets. When the current is passed through the electrodes to the sheets, heat is generated due to the higher electrical resistance where the surfaces contact each other. As the heat dissipates into the work, the rising temperature causes a rising resistance, and the heat is then generated by the current through this resistance. The surface resistance lowers quickly, and the heat is soon generated only by the materials' resistance. The water cooled copper electrodes remove the surface heat quickly, since the copper is an excellent conductor. The heat in the center has nowhere to go, as the metal of the workpiece is a poor conductor of heat by comparison. The heat remains in the center, melting the metal from the center outward. As the heat dissipates throughout the workpiece in less than a second the molten, or at least plastic, state grows to meet the welding tips. When the current is stopped the copper tips cool the spot weld, causing the metal to solidify under pressure. Some coatings, such as zinc, cause localized heating due to its high resistance, and may require pulsation welding to dissipate the unwanted surface heat into the copper tips.

If excessive heat is applied, or applied too quickly, the molten area may extend to the outside, and with its high pressure (typically 30,000 psi) will escape the containment force of the tips with a burst of molten metal called expulsion. When this occurs, the metal will be thinner and have less strength than a weld with no expulsion. The common method of checking a weld is a peel test, technically called "coach peel", as expulsion weakens the material by thinning, and makes it pass the peel test easier. A better test is the tensile test, which is much more difficult to perform, and requires calibrated equipment.

Source : Wikipedia

Lowongan kerja Bank-2008 - Career

Bank UOB Buana is a well established exchange bank since 1956. In coming years, we will pursue aggressive growth and needs several qualified individuals to fill this position:

Relationship Manager ( Code : PRB - RM )

Location: Jakarta

RESPONSIBILITIES

1. To acquire new clients.
2. To meet annual target on revenue basis.
3. To monitor balance of clients transactions.

4. Deliver and maintain best service to clients professionally.
5. Execute, comply and maintain audit requirements and procedures.
6. To cross sell other banking products to clients.

QUALIFICATION

1. Male/ female
2. University degree from reputable universities, minimum bachelor degree (s1).
3. Fluent in English.
4. Minimum 1 year Banking experience.
5. Excellent communication skill, Client management, Engage with high-end profile of clients.
6. Strong Sales background in Consumer Banking Products, such as Investment, Treasury, and Bancassurance Products.
7. Holding WAPERD and AAJI is an advantage.
8. Have own vehicle.

Please send the CV and current photograph to:

louistanumihardja@uobbuana.com

(maximum size : 20kb)

Lowongan kerja Hotel-2008 - Career

Swiss-Belhotel International,the international manager of hotels,resorts and serviced residences in Asia and the Middle East,is looking for:
Lowongan Kerja Hotel Oktober Nopember 2008

General Managers

The General Manager will report directly to the Vice President for Operations and Development. He should be able to lead and motivate his team and ensure smooth flow of hotel operations.

We are search of a dynamic and self starter individuals,with proven track record in international hotel operations in Indonesia

Applicants may send their comprehensive Curriculum Vitea with recent photo to:

Mr. Emmanuel Guillard
Vice President of Operations and Development, Indonesia
Regional Office Swiss-Belhotel International, Indonesia
Hotel Ciputra 7th floor,Suite 701,Jl. Letnan Jendral S. Parman, Jakarta 11470
E-mail: secvp-ind@swiss-belhotel.com

Only short-listed candidates will be notified

Lowongan kerja Nov-2008 - Career

PT. Fajar Gemilang Wilson Engineering: Commissioning Engineers
Posting date : Saturday, October 18, 2008 Expiry date : Saturday, November 01, 2008
Lowongan Kerja Teknik Nopember 2008
Our company is in the generation and engine business. We are looking for a dynamic person to join us as:
COMMISSIONING ENGINEERS
(Based in Singapore)

Requirements:
• Min. Diploma in Engineering with some working experience.
• Good English communication and report writting skill.

• Has good analytical skill.
• Familiar with electrical control system.
• Experience with Caterpillar engines preferred.

Responsibilities:
• To carry out site installation inspection.
• Liaise with customer on correct installation and application.
• Start-up and commissioning of engine driven generator set, pump set and marine propulsion engine on vessel, offshore rig and power house on land.

Interested applicants; please apply with full particulars of qualifications, experience, expected salary and contact number in English to:

PT. FAJAR GEMILANG WILSON ENGINEERING
JI. Pakin Blok D No. 12 (Komplek Rukan Mitra Bahari)
Jakarta Utara 14440
E-mail: fajargwe@indosat.net.id

Lowongan kerja PT. Commteck Agung - Career

Kategori	:	Information Technology (I.T.)
Posisi	:	MANAGER IT
Lokasi	:	Medan,
Media	:	Jawa Pos
Pendidikan	:	Sarjana/S1
Pengalaman Kerja	:	1-2 tahun
Jenis Kelamin	:	Pria & Wanita
Gaji	:	Not Specified
Posting Date	:	2008-10-28
Due Date	:	2008-11-08
Persyaratan
Perusahaan yang bergerak dibidang Telecommunication & Networking membutuhkan: MANAGER IT Persyaratan: 1. Pria maksimal usia 30-tahun. 2. S1 Teknik Komputer, Teknik Informatika atau Teknik Telekomunikasi 3. Pengalaman min. 2 thn dalam desain solusi network (WAN) dengan semua media akses (tembaga, FO, radio & radio IP) 4. Pengalaman dalam setting & konfigurasi router CISCO &VOIP GATEWAY & lainnya. 5. Mempunyai sertifikat CCNP yang masih aktif 6. Bersedia ditempatkan di Medan Good Income & Facilities Kirim Lamaran selambat2nya 10 hari dari tgl iklan terbit ke PT. COMMTECH AGUNG Jl. Jend. Gatot Subroto No. 26/44 It 2. Medan 20114 atau Via Email info@commtechagung.com

Lowongan kerja PT. Badak NGL - Career

Kategori	:	Engineering
Posisi	:	Sr. engineer, Engineer, Lead Engineer, Specialist, Electrical Materiel (ME), Group Head, Fire/Safety &Environment (FSE)
Lokasi	:	Jakarta,
Media	:	Jawa Pos
Pendidikan	:	Diploma
Pengalaman Kerja	:	1-2 tahun
Jenis Kelamin	:	Pria & Wanita
Gaji	:	Not Specified
Posting Date	:	2008-10-28
Due Date	:	2008-11-05
Persyaratan
CHALLENGING OPPORTUNITY PT Badak NGL, a world class natural gas liquefaction company operating & (eight) sophisticated LNG Plants in East Kalimantan, cordially Invites experienced professionals to occupy the following vacant positions: A) Sr. engineer Instrumentation (ENG/B) Electrical (ELC/B) Rotating Equipment (ROT/B) process Train (PRC/B) B) Engineer Utilities (UTL/C) Inspection (INS/C) Reliability Based Maintenance (RBM/C) DCS System (DCS/C) DCS Hardware (DCH/C) Civil (CVL/C) Electrical (ELC/C) Mechanical (MCH/C) C) Lead Engineer Instrument (INT/A) Mechanical (MCH/A) D) Specialist, Electrical Materiel (ME) E) Group Head, Fire/Safety &Environment (FSE) F) Chemist (CMS) G) legal Heed (LGL) Requirement : - Sr. Engineer with minimum 5-8 years of experience - Engineer with minimum 3-4 years of experience - Lead Engineer with minimum 7-10 years of experience - Specialist, Electrical Materiel with minimum 1-7 years of experience - Group Heed with minimum 5-10 years experience - Chemist with minimum 34 years experience - Legal Head with minimum 10 years experience General Requirement -University degree In related discipline with minimum GPA 2,7S (kale 4) Male/Female, maximum 38 years old as of December 31, 2005 -Working experience In on a gas, petrochemical Industry, or multinational enginering company with related field. -Familiar with regulations, codes, standards In oil � gas Industry -Have strong leadership, aggressive attitude and team buildingwork mindset -Excellent command In oral and written English (Minimum TOEFL 500) We offer a comprehensive benefits and compensation package designed to meet your qualification. We also provide housing, school, sport and recreation facilities which will serve you and your family with attractive environment. If you would like to take the challenges, please send your application and CV not later than 05 November 2008 (please quote POSITION TITLE 8 CODE you are applying for in \\\"subject\\\' line) E-mail : Recruitment@badaking.co.ld Website : www.badaking.co.id

Characteristics of boiler feed water

Water absorbs more heat for a given temperature rise than any other common inorganic substance. It expands 1600 times as it evaporates to form steam at atmospheric pressure. The steam is capable of carrying large quantities of heat. These unique properties of water make it an ideal raw material for heating and power generating processes.
All natural waters contain varying amounts of dissolved and suspended matter and dissolved gases the amount of minerals dissolved in water varies from 30 g/l in sea water to anything from 0.005 to 1500 mg/l in fresh water supplies. Since water impurities cause boiler problems, careful consideration must be given to the quality of the water used for generating steam.
The composition of boiler feed water must be such that the impurities in it can be concentrated a reasonable number of times inside the boiler, without exceeding the tolerance limits of the particular boiler design. If the feed water does not meet these requirements it must be pretreated to remove impurities. The impurities need not be completely removed in all cases, however, since chemical treatment inside the boiler can effectively and economically counteract them.

Feed-water purity is a matter both of quantity of impurities and nature of impurities: some impurities such as hardness, iron and silica are of more concern, for example, than sodium salts. The purity requirements for any feed-water depend on how much feed water is used as well as what the particular boiler design (pressure, heat transfer rate, etc.) can tolerate. Feed-water purity requirements therefore can vary widely. A low-pressure fire-tube boiler can usually tolerate high feed-water hardness with proper treatment while virtually all impurities must be removed from water used in some modern, high-pressure boilers.
Only relatively wide ranges can be given as to maximum levels of alkalis, salt, silica, phosphates etc, in relation to working pressure. The actual maximum levels must be obtained fro the boiler manufacturer, who will base them on the characteristics of the boiler in question.

The following tables are extracts of recommended levels from APAVE (Association of electrical and steam unit owners), up to pressures of 100 bar for medium steaming rates and for volumes of water in the chambers sufficient to properly control the blow down rates, and from ABMA (American Boiler Manufacturers Association) in its standard guarantee of steam purity.

Source :http://www.lenntech.com

Boiler Feed Water

A boiler is a device for generating steam, which consists of two principal parts: the furnace, which provides heat, usually by burning a fuel, and the boiler proper, a device in which the heat changes water into steam. The steam or hot fluid is then recirculated out of the boiler for use in various processes in heating applications.

The water circuit of a water boiler can be summarized by the following pictures:

The boiler receives the feed water, which consists of varying proportion of recovered condensed water (return water) and fresh water, which has been purified in varying degrees (make up water). The make-up water is usually natural water either in its raw state, or treated by some process before use. Feed-water composition therefore depends on the quality of the make-up water and the amount of condensate returned to the boiler. The steam, which escapes from the boiler, frequently contains liquid droplets and gases. The water remaining in liquid form at the bottom of the boiler picks up all the foreign matter from the water that was converted to steam. The impurities must be blown down by the discharge of some of the water from the boiler to the drains. The permissible percentage of blown down at a plant is strictly limited by running costs and initial outlay. The tendency is to reduce this percentage to a very small figure.

Proper treatment of boiler feed water is an important part of operating and maintaining a boiler system. As steam is produced, dissolved solids become concentrated and form deposits inside the boiler. This leads to poor heat transfer and reduces the efficiency of the boiler. Dissolved gasses such as oxygen and carbon dioxide will react with the metals in the boiler system and lead to boiler corrosion. In order to protect the boiler from these contaminants, they should be controlled or removed, trough external or internal treatment.

Source : http://www.lenntech.com

Lowongan kerja Viar Motor -Career

DIBUTUHKAN SEGERA

1. MARKETING COMMUNICATION MANAGER (MCM)
2. AREA MARKETING MANAGER (AMM)
3. AREA ADMINISTRATION MANAGER (AAM)
4. KEPALA CABANG (KCB)
5. RECRUITMENT & TRAINING MANAGER (RTM)
6. REMUNERATION MANAGER (RMM)
7. LEGAL MANAGER (LGM)
8. ENGINEERING MANAGER (EGM)
9. PPIC MANAGER (PCM)
10. MECHANIC TRAINER SUPERVISOR (MTS)

Persyaratan:

Laki-laki/perempuan, umur max. 40 th

Pendidikan min. D3, lebih disukai No.3 Accounting & No.5 Psikologi

No.1 menguasai visual art. Punya relasi luas dengan media nasional dan lokal dan mampu menyusun budget promosi dan bersedia melakukan perjalanan dinas

Pengalaman kerja min. 2 th, lebih disukai No.2, 4, 8, 9, 10 dibidang otomotif serta mampu membuat test/psikotest dan bisa membuat sistem assessment, mampu membuat program training/punya relasi dengan recruit,training center(5)

No.6 punya ketelitian tinggi & mengetahui sistem pengupahan serta kesejahteraan

No.7 menguasai hokum perdata & HAKI

Pengalaman kerja min. 2 th dibidang riset dan quality assurance sepeda motor 4 tak (8), memahami serta mempunyai sertifikat sebagai trainer motor 4 tak (10)

Bersedia melakukan perjalanan dinas luar kota dan khusus untuk No.3 bersedia ditempatkan di daerah, No.8 & 9 penempatan di Semarang

Kirim lamaran lengkap ke:

HR DEPARTMENT VIAR MOTOR

PO BOX 1164 JKT 14011

JAKARTA

Email: recruitment_viar@yahoo.co.id

Condensate Polishers

Another variation of the standard demineralizer system is the condensate polisher. Many high-pressure boiler systems incorporate a vessel loaded with strong acid cation resin or a combination of cation and anion resin to polish the steam condensate coming from turbogenerator surface condensers. Because many of these systems return a high percentage of their steam condensate as boiler feed water makeup, the polishers serve to insure that any contaminants that might enter the condensate (as from the condenser leaks) are removed prior to reuse.

In the past, condensate polishers loaded only with strong acid cation resin were regenerated with salt. Because the sodium emanating from these units during the exchange process is detrimental to the control of high pressure boiler water treatment programs, morpholine or ammonia has been substituted in many cases. Before either of these amines are used for regeneration, the polisher resin must first be put in the hydrogen form by regeneration with sulfuric acid. Next, the polisher is regenerated with the amine, which readily exchanges for the hydrogen. During normal operation, the morpholine or ammonia exchanges for the more objectionable cations (Ca⁺⁺, Mg⁺⁺, etc.). Regeneration and operation of a mixed-bed polisher is identical to that of a standard demineralizer polisher. The only drawback to the operation of a mixed-bed polisher is that it removes any neutralizing amine fed to the boiler system and therefore loses considerable capacity even though no other contaminant exists.

Mixed-Bed Polishers

In very high-pressure boiler operations, even trace contaminants are extremely detrimental. Demineralized water requirements are more stringent than can be produced by the two-bed unit. To cope with these specifications, many operations follow the two-bed demineralizer with a mixed-bed polisher. The mixed bed polisher consists of a special vessel into which are loaded both strong base anion and strong acid cation resins. The cation resin anion, being denser, is always on the bottom of the vessel after backwashing. The regenerant piping is designed so that caustic enters the top of the vessel, flows down through and regenerates the strong base anion resin, and exits the side of the vessel near the interface between the anion and cation resins. Similarly, the sulfuric acid enters the side of the vessel near the resin interface and flows downward through the strong acid cation resin, regenerates it, and flows out of the bottom of the vessel to the sewer. Prior to the addition of the caustic, the vessel is filled with water and kept under pressure (blocking flow) to insure that no caustic channels down to the cation resin before it leaves the waste line at the resin interface.

After regeneration, air is admitted to the bottom of the vessel by opening the vent. This is called air mix and serves to commingle the resins in a random fashion. As the anion and cation resins mix, the result is a vessel filled with small two-bed demineralizers. Each cation resin bead and its companion anion resin bead function as a two bed unit. The combinations on the top that receive the water first are successful in removing a great percentage of the contaminants entering the unit. Each pair below remove, in succession, a high percentage of the contaminants in the water passing the adjacent pair of resin beads. Extremely high-quality effluent water is possible with this arrangement. The water generally contains silica and sodium in the parts per billion range.

Weak Base Anion

A weak base anion resin does not have the ability to remove weak acid anions (silica and carbon dioxide). It does, however, have a high capacity (kg/ft3) for the anions associated with the strong acids (SO₄^-, Cl^-, NO₃^-, etc.). The weak base anion resin would be the resin of choice where a decarbonator was in place at the cation effluent and where silica levels in the treated water were not a major consideration.

A demineralizer train that does not incorporate a decarbonator after the cation unit would be a good candidate for an anion bed consisting of a combination of weak and strong base resins. The weak base resin would be loaded on top of the strong base resin during the initial resin installation. During normal operation, the resin bed would be regenerated prior to backwashing. This is necessary to prevent the mixing of the two resins during backwash. In their exhausted state, the density of the resins is very nearly the same. In the regenerated state, their densities are different enough for the resins to separate during backwashing. Consequently, the weak base resin is always on top. This is the preferred position, because it insures that the resin with the greatest capacity for the strong acid anions receives the effluent from the strong acid cation first. Another advantage of this arrangement is that, like the strong base anion resins, the weak base resins also absorb organics; however, the organics absorbed by a weak base resin are removed during standard regeneration. This helps protect the strong base resin from irreversible organic fouling.

Strong Base Anion

A strong base anion resin removes the anions associated with the weak acids in the effluent from a strong acid cation unit. Specifically, strong base anions remove silica (from H₂SiO₃) and carbon dioxide from H₂CO₃ (carbonic acid). In addition, the strong base anion resin removes anions associated with the strong acids in the strong acid cation effluent. Sulfate (from H₂SO₄), chloride (from HCI), and other anions are removed. The exchangeable anion is OH^-, which is picked up by the strong base anion resin during regeneration with caustic (NaOH). The cation in the water passing through unmodified (hydrogen ion is the cation) combines with the OH- liberated during the exchange and leaves the anion unit as molecules of water (H₂0). Since pure water is nonconductive, the conductivity of the effluent from a strong base anion unit is very low, about 1.9 micromhos. Sodium slippage through the strong acid cation unit combines with the liberated OH^- in the anion effluent as NaOH. Because NaOH is more conductive than H₂0, the sodium slippage through the cation increases as does the conductivity of the anion effluent.

One helpful tip to remember is that if strong acid cation resin ever gets into the anion unit (due to a bad strainer in the cation vessel bottom), it will wind up on the bottom of the anion unit because of its higher density, and will pick up sodium during the anion regeneration cycle. When the anion is put back in the service cycle, sodium will leak from the cation resin into the anion effluent and give a higher than normal anion effluent conductivity. This problem can be verified by having samples of cation effluent and anion effluent analyzed for sodium by atomic absorption. Any significant difference between the sodium levels in and out of the cation resin means that sodium has migrated into the anion vessel. This situation can be very troublesome, because most high-pressure boiler water treatment programs are adversely affected by sodium intrusion.

Strong base anion resins are quoted as having two capacities: salt-splitting capacity and total capacity. The so-called salt-splitting capacity of a strong base anion resin is a measure of its ability to remove silica and carbon dioxide. The total capacity is a combination of the salt-splitting capacity and the resin's capacity to remove SO4^-, Cl^-, NO₃^- etc.

Strong base anion resins also absorb organics from the water going through them. Most source waters contain some organic compounds. Surface waters are notorious for their propensity to carry a combination of iron and organic compounds. These compounds pass through the cation unit because the iron is not in the form of free ions. When it reaches the anion, on the other hand, the anion resin absorbs the compound and, by analysis, appears to be fouled with iron. What is really there is the iron/organic complex. This material is not removed during regeneration it occupies exchange sites normally reserved for other anions. The final result is a reduction in the capacity of the anion train.

Anion resins also remove other forms of organics during regeneration. The organics that are removed not only occupy valuable exchange sites but also react with the resin to alter its character. This alteration manifests itself in the transformation of the salt-splitting capacity of the resin to strong acid capacity. As such, the anion resin begins to lose its ability to remove silica and carbon dioxide but shows an increase in its capacity to remove the strong acid anions. The total capacity of the resin does not decrease, but its salt-splitting capacity does. The end result in a system providing water for a high-pressure boiler will be shorter and shorter run lengths, because the silica level in the effluent of the anion unit is the main control parameter.

Microbiological fouling can also occur in the anion unit. Fungi grow nicely in an anion unit. Treatment with a solution of formaldehyde is one method of sterilizing an anion train.

Weak Acid Cation

Certain waters that contain a high percentage of hardness associated with alkalinity can be economically treated by passage through a weak acid cation resin. By definition, the weak acid resin will remove Ca⁺⁺, Mg⁺⁺, and Na⁺ which enters the bicarbonate (HCO₃)^- form. Because most industrial water sources contain some noncarbonate hardness (CaSO₄, etc.), it is necessary to follow the weak acid cation unit with a strong acid cation unit to achieve truly demineralized water.

Weak and strong acid cation resins can be placed in different vessels or they can be placed in two distinct layers in the same vessel. The regeneration efficiency of a weak acid resin is very high compared to that of a strong acid resin. Therefore, it is possible to utilize the regenerant acid stream from the strong acid unit to regenerate the weak acid unit. When weak and strong acid cation resins are loaded into the same vessel, the strong acid resin settles on the bottom of the unit after backwash because of the density difference between the two resins. Because the weak acid resin contains some strong acid sites, after regeneration with sulfuric acid, a 10% brine solution must be passed through the unit. The brine solution exhausts any strong acid sites in the weak acid resin and regenerates the strong acid resin in the sodium form. If this is not done when raw water enters the weak acid resin, noncarbonate hardness exchanges at the strong acid sites. FMA exits the weak acid resin and prevents the exchange of residual noncarbonate hardness in the strong acid resin. Normally, a weak acid resin produces FMA for 40-60% of its service cycle. This combination would not be suitable for higher pressure boiler applications because of the presence of excess sodium in the effluent from the sodium-form strong acid resin.

Regeneration of a weak acid cation resin with sulfuric acid must be carefully monitored to insure that the acid concentration during the regeneration does not exceed 0.7%. Higher concentrations of sulfuric acid can react with the Ca⁺⁺ in the exchange sites of the exhausted resin and result in the precipitation of calcium sulfate (CaSO₄). Calcium sulfate, or gypsum, is insoluble even in the concentrated form of many acids. Often, mechanical removal is the only satisfactory way to rid the resin of this contaminant. From an operational standpoint, it is objectionable because it produces a pressure drop across the unit.

Dealkalization

One of the troublesome constituents in water used as a source of makeup for boiler systems is alkalinity. The so-called total alkalinity of a water is the sum of the CO₃ and OH⁺ found in that solution. The CO₃ portion of the total alkalinity is especially troublesome. As raw water is processed through a strong cation unit in a demineralizer train, the Ca or Mg normally associated with the CO₃ is exchanged for H⁺ and the cation effluent contains H₂CO₃. This acid, called carbonic acid, is very unstable. It disassociates into carbon dioxide (CO2) and water very rapidly. For this reason, many strong acid cation units are followed by a mechanical device called a decarbonator. A decarbonator is nothing more than a vessel filled with pall or Raschig rings supported on a grid over a plenum. A fan blows atmospheric air up through the fill and out a vent at the top of the tank or vessel. Carbon dioxide, which breaks out of the strong acid cation effluent stream, exists at the top. The effluent from the decarbonator normally contains 10 ppm CO₂.

Decarbonization of the strong acid cation effluent can also be accomplished by passing the acidic solution through a strong base anion resin that has been regenerated with caustic. A more complete discussion of this process follows.

Strong Acid Cation

As mentioned previously, the strong acid cation unit contains a zeolite resin that is regenerated with sulfuric acid (HCI can also be used, but it is more expensive than H₂SO₄). As the untreated water passes through the strong acid cation unit, the hydrogen ions that occupy the exchange sites in the resin are replaced by Ca, Mg, Fe, etc., ions. The companion ions of the cations removed-CO₃, SO₄, Cl, N0₃, PO₄, etc.-pass through the resin and link up with the rejected hydrogen to form the strong acids H₂CO₃, H₂SO₄, HCI, HNO₃, H₃PO₄, etc. Obviously, the effluent from a strong acid cation unit is very acidic-, it often has a 2.0-3.0 pH. For this reason, the cation vessel and the interconnecting piping and valves are lined with rubber.

The order of ionic preference for a strong acid resin is:

1. Hydrogen

2. Calcium

3. Magnesium

4. Potassium

5. Sodium

As one might expect, sodium, the least preferred cation, is also the most weakly bound. As a strong acid cation unit approaches the limit of its capacity, the ions shown in the list above begin to leak through in reverse order, i.e., sodium will leak first, followed in order by potassium, magnesium and calcium. In fact, a strong acid cation resin's affinity for sodium is so low that some sodium will always leak through, even when the resin is freshly regenerated.

In actual operation, if a cation unit is to be run to near its "break" point for economic reasons, a parameter known as free mineral acidity is monitored to determine when exhaustion is approaching. Free mineral acidity, or FMA, is present when the water pH is less than 4.3 (the methyl purple or methyl orange end point in the total alkalinity test). By definition, FMA = the sum of the sulfuric, nitrate, phosphoric and hydrochloric acid in the water sample. The FMA of the effluent from a strong acid cation unit, therefore, is proportional to the level of the total exchangeable cations in the raw water.

Monitoring the strength of the acid in the cation effluent by FMA analysis is therefore a good indicator of the performance of the unit. As the rate of cation exchange decreases due to the decrease in available exchange sites in the resin, the amount of acid in the effluent (FMA) decreases. Therefore, decreasing FMA heralds the end of the service cycle in a strong acid cation unit. Cation units are not run to exhaustion because of the need to double regenerate them to get back the total capacity and because high-pressure systems using this water could not tolerate the hardness associated with the end of the run.

In practice, most demineralizer trains are designed to produce the maximum amount of water per desired service cycle. Invariably, the limiting resin volume is that of the anion unit. Strong base resins, even when preceded by a weak base resin, can process less water than a strong acid resin. Frequently, the anion vessel is designed to accommodate the resin volume necessary to treat the desired amount of water and the strong acid cation unit dimensions are duplicated from the anion unit design. This, in effect, insures that when a train breaks, it will break on silica first. In a high-pressure system, silica intrusion is more easily handled than hardness intrusion.

A boiler system can function properly or cease operation as a result of the quality of demineralized water that is used for makeup. Even the best internal treatment programs have their limits. This is why a thorough understanding of the owner's demineralizer system is so important to the water treatment consultant. With excellent feed water, even a mediocre water treatment program can be made to work in a high pressure system. Conversely, even the best chemicals and the most carefully thought-out treatment program can fail miserably when the demineralizer system cannot be counted on to deliver a quality feed water.

Demineralization

Introduction and Purpose of Demineralization

In many process boiler systems, zeolite softening of water is not sufficient to meet feed water quality standards. In these cases (typically high pressure boilers >1000 psig), the water is demineralized. This process removes most of the mineral content of the raw water.

Demineralizers depend upon both cationic and anionic exchange processes. They can be arranged in many different combinations, based upon incoming water contaminants and desired final water quality. By the end of this chapter you should have a basic understanding of what demineralization does, how these systems work, and the basic steps necessary to troubleshoot a system.

Theory of Operation

Demineralization on a commercial scale became possible after resin manufacturers developed methods of mass producing a new form of ion exchange resin. When regenerated with caustic (NaOH), this resin removed silica and carbon dioxide from the effluent of a zeolite resin operated in the hydrogen cycle. A standard cation resin of the type commonly found in zeolite softeners, which is regenerated with sulfuric acid as opposed to salt (hence: hydrogen cycle cation), is called a strong acid cation resin. An anion resin with a strong affinity for silica and carbon dioxide is described as a strong base anion resin. An offshoot of the strong base anion resin development was the production of a chemically different resin with a strong affinity for strong-acid anions: sulfate (SO₄), chloride (CI), nitrate (NO₃), phosphate (PO₄), etc. This was called a weak base resin. The weak base resin does not remove silica or carbon dioxide, as does the strong base resin. Therefore, it cannot be used alone to produce the water purity demanded by high-pressure steam plant operations. Less caustic is required to regenerate the weak base resin and it is often coupled with a strong base resin in the same vessel to produce the most economical anion unit operation. The weak base resin is always loaded into the vessel last when the unit is readied for downflow service.

Putting the weak base resin on top of the anion resin bed uses its higher capacity for strong acid removal to insure that the strong base resin can concentrate on removing the weak acids associated with the carbon dioxide and silica (carbon and silicic acids).

The cation and anion vessels of a demineralizer train are piped in series so that the effluent of the cation unit enters the top of the anion unit and the discharge from the anion unit goes to the treated water header or into a polishing unit.

A discussion of what takes place as the raw water is processed through the various units in a demineralizer may help to explain the resins and their function.

by: http://www.gc3.com/

LOWONGAN - Teknisi Operasi PLN Sumut 2008

Kesempatan Kerja

PT. PLN (Persero) dengan visi diakui sebagai perusahaan kelas dunia yang bertumbuh kembang, unggul and terpercaya dengan bertumpu pada potensi insani, membuka kesempatan bagi generasi muda terbaik untuk bergabung dan mengembangkan karir menjadi pegawai PT. PLN (Persero) Wilayah Sumatera Utara, sebagai: Teknisi Operasi/Pemeliharaan Distribusi.

Persyaratan Fisik:
• Jenis kelamin laki-laki, belum menikah
• Usia maksimal 21 tahun (kelahiran tahun 1987 dan sesudahnya)
• Tinggi badan minimal 160 cm
• Berat badan proporsional
• Sehat rohani dan jasmani, tidak buta warna, tidak berkacamata dan tidak berkontak lensa.
• Tidak pernah menggunakan narkoba / NAPZA dan tidak bertato

Persyaratan Administrasi:
1. lulusan SMK jurusan listrik (elektro arus kuat / ketenagalistrikan)
2. nilai rapor / transkrip terakhir:
matematika: nilai minimal 6 (enam)
ilmu listrik: nilai minimal 7 (tujuh)
fisika: nilai minimal 7 (tujuh)
3. bersedia mengikuti pendidikan ikatan dinas selama 1 (satu) tahun dan tidak menikah dalam masa pendidikan

Tahap Seleksi:
Seleksi dilakukan dengan sistem gugur dengan tahapan
1. administrasi
2. akademis & psikologi
3. wawancara
4. tes kesehatan

Lain-lain:
1. tidak diadakan korespondensi dan hanya lamaran yang masuk melalui PO BOX yang akan diproses
2. pelamar tidak dipungut biaya
3. pelamar yang dinyatakan lulus pada seluruh tahapan seleksi akan dipanggil mengikuti Program Beasiswa Pendidikan Setara Diploma 1
4. pelamar yan dapat menyelesaikan program beasiswa pendidikan setara D1 diatas akan diangkat menjadi pegawai teknisi operasi / pemeliharan distribusi dan ditempatkan di seluruh wilayah kerja PT. PLN (Persero) wilayah Sumatera Utara
5. surat lamaran yang pernah dikirim sebelum diterbitkannya pengumuman ini dinyatakan tidak berlaku
6. apabila dikemudian hari DATA berkas surat lamaran ternyata tidak benar maka peserta dinyatakan GUGUR
7. keputusan panitia tidak dapat diganggu gugat
8. lamaran yang masuk ke panitia penerimaan menjadi hak milik panitia sehingga tidak bisa diambil kembali.

Cara mengajukan lamaran
Surat lamaran diajukan kepada “Panitia Rekrutmen” dengan melampirkan:
a. surat lamaran yang ditandatangani
b. fotocopy ijazah SMK yang dilegalisir
c. fotocopy nilai raport / transkrip SMK (kelas 1,2,3) yang dilegalisir
d. fotocopy akte kelahiran / surat kenal lahir
e. fotocopy KTP yang masih berlaku
f. CV / Daftar riwayat hidup yang ditandatangani
g. Pas photo berwarna 4 x 6 sebanyak 3 (tiga) lembar
h. Surat keterangan berbadan sehat dan tidak buta warna dari dokter rumah sakit / puskesmas
i. Surat pernyataan diri diatas materai Rp.6000,- yang meliputi
1. bahwa tidak pernah terlibat dalam penyalahgunaan narkotika, zat adiktif lian dan tindak criminal
2. kesanggupan bekerja sebagai teknisi operasi dan pemeliharaan distribusi dan bersedia ditempatkan diseluruh wilayah kerja PT. PLN (Persero) wilayah Sumatera Utara.
3. bahwa tidak akan menikah selama 1 (satu) tahun dalam masa pendidikan
4. bahwa tidak akan menuntut pengakuan atas ijazah yang lebih tinggi dari ijazah SMK yang dimiliki.

Lamaran kami terima paling lambat tanggal 2 November 2008 (stempel pos)

Lamaran ditujukan kepada:
PANITIA REKRUTMEN TENAGA OPHARDIS
PT PLN (PERSERO) WILAYAH SUMATERA UTARA
PO. BOX 2000 MEDAN

LOWONGAN - Turbocharger Specialist Goltens Jakarta

BERPENGALAMAN, CERTIFIED, 26 OKTOBER 2008

Goltens is an international group within Marine, Offshore, Stationary Power Plants & Industrial fields. Goltens handles projects of varying size and complexity from turn-key with a variety of disciplines involved, through diesel engine parts reconditioning, equipment & machinery overhaul and a multitude of in-situ machining services. Due to rapid growth of the company, we now urgently need qualified persons to fill the following positions in Jakarta.

Turbocharger Specialist (TS)

Requirements:
- Male between 27 - 35 years old.
- Supervisory and hands-on work required for on board & shop work.
- Candidate must have strong experience in full disassembly/reassembly, overhaul works required for Turbo Charger such as ABB, MET, HOLSETS, Napier, K3, etc.
- Min. 3 years hand-on experience in Turbo Charger, after sales service, trouble-shooting or other related fields
- Marine engineering degree and/or licensed engineer preferred.
- Able to work independently & willingness to travel & work on site.
- Fluency in English (written and spoken) will be an advantage.

Interested candidates should submit CV with recent photograph, position code, past and present employment and professional qualification, within 8 November 2008.

PT. Goltens Jakarta
JI. Danau Sunter Barat Blok A1 No. 1 Jakarta Utara 14350
Email: Jakarta@goltens.com

LOWONGAN - Construction Engineer PT. DEN

BERPENGALAMAN S1, 26 OKTOBER 2008

We are a company in the supply of power generation services and equipment, committed to technological innovation and excellence, are looking for high quality candidates for the position of:

Construction Engineer (Code: CE)

Requirements:
• Min. Bachelor Degree in Mechanical Engineering or related subject
• Male, Max. 35 years old.
• Min. 3 years experience in site construction of Thermal Power Plant or Industrial plant.
• Willing to be located in project site and flexible on work hours.
• Familiar with reference CODE of Construction Power Plant
• Good Spoken Written of English
• Computer literate (Windows applications).

If you meet the above qualification, please send your application, CV and recent photograph with the position not later than 8 November 2008 to:

hrd@den-indonesia.com
or
Postal to:
PT. Dinamika Energitama Nusantara
Juanda Business Centre blok C-8
JI. Ir. H. Juanda no.1, Waru-Sidoarjo

Lowongan Bank Mandiri - Corporate Banking Officer

Klien kami, Bank Mandiri (Persero) Tbk, membutuhkan orang-orang yang berkualitas untuk posisi berikut :

Corporate Banking Officer (CSO)

Kualifikasi:

• Pendidikan Formal minimal S1, semua jurusan.
• Menguasai product knowledge Bank khususnya yang berkaitan dengan produk kredit korporasi dan Invesment Banking.
• Berpenampilan dan berkepribadian menarik.
• Memiliki selling & negotiating skills.
• Memiliki kemampuan berkomunikasi aktif baik lisan dan tulisan dalam bahasa Indonesia dan bahasa Inggris dengan baik.
• Berpengalaman di bidang kredit dan investment banking.
• Memiliki relasi yang luas terutama dengan perusahaan-perusahaan korporasi.

Tanggung Jawab:

• Melakukan identifikasi calon nasabah baru, menyusun strategy akuisisi dan melakukan analisa potensi bisnis yang akan diperoleh dari nasabah baru yang menjadi target akuisisi.
• Melaksanakan akuisisi sesuai target dan strategy yang telah ditetapkan dengan melakukan aktivitas selling terhadap seluruh produk Corporate Banking yang ada.
• Membina relationship yang seluas-luasnya dengan perusahaan-perusahaan korporasi yang telah ditetapkan sebagai target nasabah segmen korporasi sesuai dengan target Group dan Direktorat Corporate Banking untuk menunjang tercapainya target ekspansi yang telah ditetapkan.

Kirimkan CV dalam format MS Word , dengan mencantumkan gaji terakhir dan gaji yang diharapkan melalui email : resume@sintesa-resourcing.com

Cantumkan posisi yang dituju CBO di subyek email. Only short listed candidates will be notified.

LOWONGAN CV. COSA ARANDA NETWORK (WEB DEVELOPER)

URGENTLY REQUIRED

CV Cosa Aranda Network, perusahaan yang bergerak di bidang media, promosi, dan bisnis internet, membuka lowongan untuk posisi: WEB DEVELOPER.

Persyaratan:

• Pria/Wanita, berpenampilan menarik
• Usia maks. 22 tahun
• Menguasai PHP, MySQL, HTML, CSS, JavaScript, dan AJAX
• Memahami konsep Web 2.0
• Mampu membuat desain web
• Pengalaman tidak diutamakan
• Dapat bekerja dalam tim dan di bawah tekanan
• Mampu berbahasa Inggris pasif

Pelamar yang memenuhi syarat harap datang langsung untuk walk-in interview ke:

CV Cosa Aranda Network
Ruko Delta Permai IB/16
Panjangjiwo, Surabaya

pada hari Senin - Jum’at, pukul 09.00 - 16.00 dengan membawa surat lamaran lengkap.