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cadmium electroplating consuming 6 of the global production is used in the aircraft industry reduce corrosion of steel components this coating is passivated by chromate salts a limitation of cadmium plating is hydrogen embrittlement of high @@ strength steels from the electroplating process therefore steel parts heat @@ treated to tensile strength above 1300 mpa ( 200 ksi ) should be coated by an alternative method ( such as special low @@ embrittlement cadmium electroplating processes or physical vapor deposition )
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titanium embrittlement from cadmium @@ plated tool residues resulted in banishment of those tools ( and the implementation of routine tool testing to detect cadmium contamination ) in the a @@ 12 / sr @@ 71 u @@ 2 and subsequent aircraft programs that use titanium
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= = = nuclear fission = = =
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cadmium is used in the control rods of nuclear reactors acting as a very effective neutron poison to control neutron flux in nuclear fission when cadmium rods are inserted in the core of a nuclear reactor cadmium absorbs neutrons preventing them from creating additional fission events thus controlling the amount of reactivity the pressurized water reactor designed by westinghouse electric company uses an alloy consisting of 80 silver 15 indium and 5 cadmium
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= = = compounds = = =
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cadmium oxide was used in black and white television phosphors and in the blue and green phosphors of color television cathode ray tubes cadmium sulfide ( cds ) is used as a <unk> surface coating for photocopier drums
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various cadmium salts are used in paint pigments with cds as a yellow pigment being the most common cadmium selenide is a red pigment commonly called cadmium red to painters who work with the pigment cadmium provides the most brilliant and durable yellows oranges and reds so much so that during production these colors are significantly toned down before they are ground with oils and binders or blended into watercolors gouaches acrylics and other paint and pigment formulations because these pigments are potentially toxic users should use a barrier cream on the hands to prevent absorption through the skin even though the amount of cadmium absorbed into the body through the skin is reported to be less than 1
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in pvc cadmium was used as heat light and weathering stabilizers currently cadmium stabilizers have been completely replaced with barium @@ zinc calcium @@ zinc and organo @@ tin stabilizers cadmium is used in many kinds of solder and bearing alloys because a low coefficient of friction and fatigue resistance it is also found in some of the lowest @@ melting alloys such as wood 's metal
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= = = laboratory uses = = =
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helium cadmium lasers are a common source of blue @@ ultraviolet laser light they operate at either 325 or 422 nm in fluorescence microscopes and various laboratory experiments cadmium selenide quantum dots emit bright luminescence under uv excitation ( he @@ cd laser for example ) the color of this luminescence can be green yellow or red depending on the particle size <unk> solutions of those particles are used for imaging of biological tissues and solutions with a fluorescence microscope
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cadmium is a component of some compound semiconductors such as cadmium sulfide cadmium selenide and cadmium telluride used for light detection and solar cells <unk> is sensitive to infrared light and can be used as an infrared detector motion detector or switch in remote control devices
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in molecular biology cadmium is used to block voltage @@ dependent calcium channels from fluxing calcium ions as well as in hypoxia research to stimulate proteasome @@ dependent degradation of <unk> @@ 1α
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= = = cadmium @@ selective sensors = = =
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cadmium @@ selective sensors based on the <unk> <unk> have been developed for imaging and sensing of cadmium in cells
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= = biological role = =
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cadmium has no known function in higher organisms but a cadmium @@ dependent carbonic anhydrase has been found in some marine diatoms the diatoms live in environments with very low zinc concentrations and cadmium performs the function normally carried out by zinc in other <unk> this was discovered with x @@ ray absorption fluorescence spectroscopy ( <unk> )
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the highest concentration of cadmium is absorbed in the kidneys of humans and up to about 30 mg of cadmium is commonly inhaled throughout human childhood and adolescence
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cadmium can be used to block calcium channels in chicken neurons analytical methods for the determination of cadmium in biological samples have been reviewed
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= = environment = =
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the biogeochemistry of cadmium and its release to the environment has been the subject of review as has the speciation of cadmium in the environment
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environmental concentrations can exceed adverse @@ effect @@ thresholds in cadmium @@ polluted ecosystems ( eg in some parts of europe ) and pollutant cadmium can accumulate in invertebrates earthworms seabirds marine mammals plants and some algal species effects in animals include kidney disorders impairment of enzymes disruption of calcium metabolism and changes in cell membrane permeability excess cd uptake in plants can affect growth and metabolic processes such as photosynthesis and transpiration
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= = safety = =
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the bioinorganic aspects of cadmium toxicity have been reviewed
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the most dangerous form of occupational exposure to cadmium is inhalation of fine dust and fumes or ingestion of highly soluble cadmium compounds inhalation of cadmium fumes can result initially in metal fume fever but may progress to chemical pneumonitis pulmonary edema and death
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cadmium is also an environmental hazard human exposure is primarily from fossil fuel combustion phosphate fertilizers natural sources iron and steel production cement production and related activities nonferrous metals production and municipal solid waste incineration bread root crops and vegetables also contribute to the cadmium in modern populations
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there have been a few instances of general population poisoning as the result of long @@ term exposure to cadmium in contaminated food and water and research into an estrogen mimicry that may induce breast cancer is ongoing in the decades leading up to world war ii mining operations contaminated the <unk> river in japan with cadmium and traces of other toxic metals as a consequence cadmium accumulated in the rice crops along the riverbanks downstream of the mines some members of the local agricultural communities consumed the contaminated rice and developed itai @@ itai disease and renal abnormalities including proteinuria and <unk>
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the victims of this poisoning were almost exclusively post @@ menopausal women with low iron and other mineral body stores similar general population cadmium exposures in other parts of the world have not resulted in the same health problems because the populations maintained sufficient iron and other mineral levels thus although cadmium is a major factor in the itai @@ itai disease in japan most researchers have concluded that it was one of several factors cadmium is one of six substances banned by the european union 's restriction on hazardous substances ( rohs ) directive which regulates hazardous substances in electrical and electronic equipment but allows for certain exemptions and exclusions from the scope of the law the international agency for research on cancer has classified cadmium and cadmium compounds as carcinogenic to humans although occupational exposure to cadmium is linked to lung and prostate cancer there is still a substantial controversy about the carcinogenicity of cadmium in low environmental exposure recent data from epidemiological studies suggest that intake of cadmium through diet associates to higher risk of endometrial breast and prostate cancer as well as to osteoporosis in humans a recent study has demonstrated that endometrial tissue is characterized by higher levels of cadmium in current and former smoking females
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cadmium exposure is a risk factor associated with a large number of illnesses including kidney disease early atherosclerosis hypertension and cardiovascular diseases although studies show a significant correlation between cadmium exposure and occurrence of disease in human populations a necessary molecular mechanism has not been identified one hypothesis holds that cadmium is an endocrine disruptor and some experimental studies have shown that it can interact with different hormonal signaling pathways for example cadmium can bind to the estrogen receptor alpha and affect signal transduction along the estrogen and mapk signaling pathways at low doses
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tobacco smoking is the most important single source of cadmium exposure in the general population an estimated 10 of the cadmium content of a cigarette is inhaled through smoking absorption of cadmium through the lungs is more effective than through the gut and as much as 50 of the cadmium inhaled in cigarette smoke may be absorbed on average cadmium concentrations in the blood of smokers is 4 times 5 times greater and in the kidney 2 3 times greater than non @@ smokers despite the high cadmium content in cigarette smoke there seems to be little exposure to cadmium from passive smoking
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in a non @@ smoking population food is the greatest source of exposure high quantities of cadmium can be found in crustaceans mollusks offal and algae products however grains vegetables and starchy roots and tubers are consumed in much greater quantity in the us and are the source of the greatest dietary exposure most plants bio @@ accumulate metal toxins like cd and when composted to form organic fertilizers yield a product which can often contain high amounts ( eg over 0 @@ 5 mg ) of metal toxins for every kilo of fertilizer fertilizers made from animal dung ( eg cow dung ) or urban waste can contain similar amounts of cd the cd added to the soil from fertilizers ( rock phosphates or organic fertilizers ) become bio @@ available and toxic only if the soil ph is low ( ie acidic soils ) zinc is chemically similar to cadmium and some evidence indicates the presence of zn ions reduces cadmium toxicity
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zinc cu ca and fe ions and selenium with vitamin c are used to treat cd intoxication though it is not easily reversed
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= = = regulations = = =
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because of the adverse effects of cadmium on the environment and human health the supply and use of cadmium is restricted in europe under the reach regulation
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the efsa panel on contaminants in the food chain specifies that 2 @@ 5 μg / kg body weight is a tolerable weekly intake for humans the joint fao / who expert committee on food <unk> has declared 7 μg / kg <unk> to be the provisional tolerable weekly intake level
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the us occupational safety and health administration ( osha ) has set the permissible exposure limit ( pel ) for cadmium at a time @@ weighted average ( twa ) of 0 @@ 005 ppm the national institute for occupational safety and health ( niosh ) has not set a recommended exposure limit ( rel ) and has designated cadmium as a known human carcinogen the idlh ( immediately dangerous to life and health ) level for cadmium is 9 mg / m3
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= = = product recalls = = =
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in may 2006 a sale of the seats from arsenal fc ' s old stadium highbury in london england was cancelled when the seats were discovered to contain trace amounts of cadmium reports of high levels of cadmium use in children 's jewelry in 2010 led to a us consumer product safety commission investigation the us <unk> issued specific recall notices for cadmium content in jewelry sold by claire 's and wal @@ mart stores
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in june 2010 mcdonald 's voluntarily recalled more than 12 million promotional shrek forever after 3d collectable drinking glasses because of the cadmium levels in paint pigments on the glassware the glasses were manufactured by arc international of millville nj usa
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= first battle of maryang san =
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the first battle of maryang san ( 3 8 october 1951 ) also known as the defensive battle of <unk> ( chinese <unk> pinyin <unk> shān <unk> zhàn ) was fought during the korean war between united nations ( un ) forces primarily australian and british and the chinese communist people 's volunteer army the fighting occurred during a limited un offensive by us i corps codenamed operation commando this offensive ultimately pushed the chinese back from the imjin river to the jamestown line and destroyed elements of four chinese armies following heavy fighting the much smaller battle at maryang san took place over a five @@ day period and saw the 3rd battalion royal australian regiment ( 3 rar ) dislodge a numerically superior chinese force from the tactically important kowang @@ san ( hill 355 ) and maryang san ( hill 317 ) features in conjunction with other units of the 1st commonwealth division
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using tactics first developed against the japanese in new guinea during the second world war the australians gained the advantage of the high ground and assaulted the chinese positions from unexpected directions they then repelled repeated chinese counterattacks aimed at re @@ capturing maryang san with both sides suffering heavy casualties before the australians were finally relieved by a british battalion however with the peace @@ talks ongoing these operations proved to be last actions in the war of manoeuvre which had lasted the previous sixteen months it was replaced by a static war characterised by fixed defences reminiscent of the western front in 1915 17 a month later the chinese subsequently re @@ captured maryang san from the british during fierce fighting and it was never re @@ gained today the battle is widely regarded as one of the australian army 's greatest accomplishments during the war
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= = background = =
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= = = military situation = = =
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following general of the army douglas macarthur 's dismissal as commander @@ in @@ chief of un forces in korea he was replaced by general matthew b ridgway consequently on 14 april 1951 general james van fleet replaced ridgway as commander of the us eighth army and the united nations forces in korea the chinese spring offensive during april and may 1951 ended in its defeat while following two months of sporadic operations in mid @@ june and august the war entered a new phase with van fleet returning to the offensive in july the kansas and wyoming lines were strengthened while a limited offensive in the east @@ central sector in mid @@ august seized the high ground around the punchbowl and bloody ridge during the battle of bloody ridge in september the offensive in this sector continued targeting the next hill complex north of bloody ridge known as heartbreak ridge
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meanwhile the organisation of british commonwealth ground forces fighting in korea as part of the united nations command had undergone considerable change in the months following the battles of the imjin river and kapyong in late @@ april 1951 3 rar had been transferred from 27th british infantry brigade to the 28th british commonwealth brigade when that formation departed for hong kong meanwhile after protracted negotiations between the governments of australia britain canada india new zealand and south africa agreement had been reached to establish an integrated formation with the aim of increasing the political significance of their contribution as well as facilitating the solution of the logistic and operational problems faced by the various commonwealth contingents
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the 1st commonwealth division was formed on 28 july 1951 with the division including the 25th canadian 28th british commonwealth and 29th british infantry brigades under the command of major general james cassels and was part of us i corps since its formation the division had occupied part of the west @@ central sector of the un line approximately 48 kilometres ( 30 mi ) north of the capital seoul the 28th brigade included three infantry battalions the 1st battalion king 's own scottish borderers ( 1 kosb ) 1st battalion king 's shropshire light infantry ( 1 <unk> ) and the 3rd battalion royal australian regiment under the command of brigadier george taylor during this period 3 rar was commanded by lieutenant colonel francis hassett peace @@ talks at kaesong during july and september led to a lull in the fighting and 3 rar undertook mainly defensive duties helping to construct the defences of the kansas line south of the imjin river as well as conducting extensive patrolling on the northern side the battalion also used the reduced operational tempo as an opportunity to train reinforcements the period culminated in a limited and largely unopposed divisional advance 12 kilometres ( 7 @@ 5 mi ) north of the imjin to the wyoming line codenamed operation minden in september
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= = prelude = =
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= = = opposing forces = = =
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in late @@ september and early @@ october even while continuing the attack against heartbreak ridge van fleet developed a plan for a limited offensive in the western section known as operation commando to advance 10 kilometres ( 6 @@ 2 mi ) north of the 38th parallel with the aim of pushing chinese forces back and giving united nations forces more leverage at the truce negotiations now occurring at panmunjom operation commando was scheduled for 3 5 october 1951 and the us i corps commander lieutenant general john w o 'daniel envisioned a concept of operations in which three of the corps ' four divisions would advance on a broad front in conjunction with us 25th infantry division on the left flank of the neighbouring us ix corps seizing a new defensive line known as the jamestown line the divisions to be used in the advance included the 1st commonwealth division us 1st cavalry division and the 9th south korean division the 1st south korean division would remain in its existing position on the left flank
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in the sector occupied by 1st commonwealth division chinese communist forces were dug into a group of hills overlooking the imjin river the division faced 6 @@ 000 troops from the chinese 191st division 64th army under the overall command of xie <unk> the chinese forces were divided into three regiments of about 2 @@ 000 men each with two regiments dug @@ in in well prepared defensive positions with overhead protection and a third regiment in support the 28th brigade faced one of the two forward regiments the 571st regiment which was deployed with one battalion on hill 355 a second battalion astride hill 217 and hill 317 and a third battalion in reserve to the west
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the task allocated to the british commonwealth force was to take these positions with the intention of advancing the line from the southern bank of the imjin to a line of hills to the north in total an objective that stretched more than 15 kilometres ( 9 @@ 3 mi ) the primary objectives of the advance would be the capture of kowang @@ san ( hill 355 ) and maryang san ( hill 317 ) and the task of taking these positions was allocated to the 28th british commonwealth brigade with this formation bearing the brunt of the fighting cassels planned on capturing the jamestown line in three phases in the first phase scheduled for 3 october the 28th brigade would take hill 355 in the east @@ central sector during the second phase on 4 october the 25th brigade would assault the two hill 187 features and the south @@ western ridge running to the samichon river lastly during the third phase scheduled for 5 october the 28th brigade would capture hills 217 and 317 as such the bulk of the division 's strength would be concentrated on the right flank to be held by the 28th brigade meanwhile the 25th brigade would hold the left flank and the 29th brigade would be held in reserve while providing a battalion to each of the other brigades as reinforcements
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kowang @@ san would be assaulted during the first phase by 1 kosb with 1 <unk> and 3 rar in support while maryang san would be taken in the third phase of the operation by 3 rar and the 1st battalion royal northumberland fusiliers ( 1 rnf ) who were under commander from 29th brigade for the duration of operation commando careful reconnaissance and planning took place in the week prior to the commencement of the operation and taylor emphasised the use of indirect fires air support and infiltration tactics to limit casualties as well as the exploitation of weak points in the chinese defences in direct support of the brigade was 16th field regiment royal new zealand artillery with its 3 @@ 45 @@ inch ( 88 mm ) 25 @@ pounder field guns in addition to divisional and corps assets which included 4 @@ 2 @@ inch ( 110 mm ) mortars 3 @@ inch ( 76 mm ) howitzers and 155 @@ millimetre ( 6 @@ 1 in ) heavy artillery in total more than 120 guns and mortars also in support were two british centurion tank squadrons from the 8th royal irish hussars
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= = = preliminary operations = = =
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given the primary task of capturing hill 317 hassett studied the approaches from the air and the ground two previous attempts to take maryang san by american troops had been unsuccessful regardless utilising tactics first developed against the japanese in new guinea during the second world war of running along the tops of ridges he intended to gain the advantage of the high ground while utilising the cover afforded by the vegetation and the ease of movement along the crest @@ lines in order to assault the chinese positions from unexpected directions meanwhile the chinese defenders on maryang san were also testing a newly developed tactic called the mobile positional defense in which only small units were stationed on the hills in order to exhaust the un attackers while the bulk of the chinese defenders would later counterattack before the un forces could consolidate into their newly gained positions
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however during the first phase of the operation the australians would be tasked with capturing a chinese outpost on hill 199 to allow tanks and medium machine @@ guns to provide direct fires onto the northern and eastern slopes of hill 355 in support of an attack by the borderers from the south @@ east likewise the shropshires would assault and capture hill 208 finally then two days before the start of operation commando the 28th brigade crossed the imjin river to assemble behind the 25th brigade on 1 october the following day the 3 rar less d company and the borderers moved forward carefully into their assembly areas ready to advance the following morning c company advanced to a position 1 @@ 500 metres ( 1 @@ 600 yd ) in front of the canadian positions north @@ east of hill 355 b company was 200 metres ( 220 yd ) to the rear in the afternoon c company was subjected to heavy shelling losing one soldier wounded d company under the command of major basil hardiman was detached to 25th brigade to strengthen its extended front and it would not be available until the afternoon of 3 october
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= = battle = =
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= = = capture of hill 199 3 october 1951 = = =
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at 03 00 on 3 october b company 3 rar moved north 2 @@ 000 metres ( 2 @@ 200 yd ) toward hill 199 crossing the open valley under the cover of darkness and heavy mist a company then moved up behind c company artillery and mortar fire targeted known chinese artillery positions with counter @@ battery fire prior to dawn before switching to support the borderers in their assault on hill 355 simultaneously the shropshires were assaulting hill 208 and with the support of a squadron 8th royal irish hussars they reached the positions without opposition by 06 00 by 08 00 b company had gained the high ground to the north and then proceeded to patrol the short distance to west to the objective which was then taken with three wounded five chinese were killed and one captured by mid @@ morning both the shropshires and the australians had successfully captured their objectives
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expecting a counter @@ attack the australians on hill 199 began digging @@ in however no such attack occurred d company subsequently returned and was allocated a position between c company and the borderers c and b companies both received shelling during the day wounding two men at 10 00 a company under captain jim shelton took over the defence of hill 199 and b company went into reserve behind a company according to plan a troop of centurion tanks and a section of medium machine @@ guns were then moved up onto hill 199 and began directing their fire onto the northern slopes of hill 355 in support of the borderers meanwhile at 07 15 following preparation by artillery and mortar fire the lead british assault companies had begun to advance on hill 355 however with the chinese expecting an assault from that direction the initial british moves met strong resistance and the borderers were forced to withdraw and reorganise at 14 15 a second assault reached the objectives on the lower slopes and these gains were consolidated by nightfall
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the attack was now behind schedule indeed the borderers were still more than 1 @@ 000 yards ( 910 m ) short of their final objective and with stubborn resistance being encountered during the initial phase hill 355 would now not be secured until the afternoon of 4 october the assault was being slowed by two positions on the northeast slopes of hill 355 known as hill 220 from which the chinese held the british right flank in enfilade c company 3 rar would be detached to assist the attack on kowang @@ san the next morning with the australians tasked with outflanking the chinese defences and capturing this position heavy chinese artillery fire had also slowed progress with more than 2 @@ 500 rounds falling in the 28th brigade area in the previous twenty @@ four hours although this total was dwarfed many times over by the weight of allied artillery fired across the brigade front which included 22 @@ 324 rounds on the division 's left flank the delay also meant that the canadian attack scheduled for 06 00 the next day in the 25th brigade sector would have to be postponed until 11 00 due to the continuing requirement to use the divisional artillery in support of 28th brigade
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= = = capture of hill 220 and the fall of kowang @@ san 4 october 1951 = = =
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on 4 october c company 3 rar under the command of major jack gerke attacked the long spur running east from the peak of hill 355 known as hill 220 launching their assault at 09 00 the australians quickly killed or drove off the defenders before pressing on up the spur and routing the remainder of a chinese company reaching their objectives by 10 00 the australians then took advantage of the initiative gained so far pushing a platoon towards the summit of hill 355 amid heavy fighting the australians cleared the eastern slopes of kowang @@ san by 12 00 despite having received no orders to do so thirteen chinese were killed and three captured in the fighting while australian casualties included 11 wounded one of whom subsequently died gerke was later awarded the distinguished service order ( dso ) for his leadership c company withdrew to the rear of the 3 rar position and were replaced by d company who occupied the position held by a company 500 metres ( 550 yd ) north of hill 199 meanwhile led by a bagpiper the borderers made a simultaneous assault up the western face of kowang @@ san and fearing they may be caught between two attacks the chinese defenders abandoned hill 355 withdrawing northwest under heavy indirect fire
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given the strong resistance exhibited by the chinese the canadians expected a tough fight as 25th brigade prepared to assault its objectives as part of the second phase of the divisional plan yet with the loss of hill 355 and 210 the chinese unexpectedly withdrew from their well @@ prepared defensive positions with hill 159 and 175 captured without opposition only the 2nd battalion princess patricia 's canadian light infantry encountered any opposition before they captured the two hill 187 features losing one killed and six wounded during stiff fighting in which 28 chinese were also killed indeed the ease with which the canadians had captured their initial objectives allowed them to press on attaining their final objectives on the jamestown line by nightfall no further resistance was encountered although heavy chinese artillery fire caused a number of casualties including three killed the canadians subsequently occupied the positions they were destined to hold for the next twenty @@ two months of fighting
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