IMGHIEIXI CUU THI^T k CH T A O M A Y V A CONG IMGHf

Size: px

Start display at page:

Download "IMGHIEIXI CUU THI^T k CH T A O M A Y V A CONG IMGHf"

Abner Short
5 years ago
Views:

1 KHOA HQC CONG N O I!! IMGHIEIXI CUU THI^T k CH T A O M A Y V A CONG IMGHf s A y MOT s d LOAI IVOIMG SAlXI THUC P h A m D AN G HAT t r im m A y s A y t h U img q u a y Nguydn TSn Thinh1 t 6 m t At Dd tai Nghidn cuu c6ng nghd say nong san trdn may say thung quay da thu dugc cac kdt qua sau. Da thidt kd, chd tao dupe 01 mdy say thung quay hoan chinh 6 quy mo thi nghidm. Miy gom cac bo phan chinh: quat, dung cu do nhidt lugng, thung quay, bd din dpng va hd thdng didu khidn nhidt dp tu ddng cho may. Ciu tao cua thung sly gdm 2 try luoi dong true; d giua chua v t lidu; khoang khdng gian trong la noi dua tic nhdn sly vao dd sly vdt lidu. Nghidn cuu siy hat trdn thidt bj nay cho thiy dd im cua vat lidu sau say khd dong ddu (ldp hat mat trong va ngoai chi chdnh nhau 0,40,8%). DO chua diy cua v t lidu 90% va toe d<> quay cua thung n = 4 v/p, tdc dd tic nhan siy qua ldp hat V * 0,3 m/s cho kdt qua tdt vd nsng suit cung nhu chit lugng. May sly thung quay cd thd siy nhidu loai ndng san thyc phim dgng hat nhu: lua, ngo, ca phe, dau... Miy gon, dd chd tao, dd vin hanh, gii thdnh vira phai. Su dyng miy siy thung quay dd sly hat s cho hidu qua cao. Tu khda: May sa'y thung' quay, san phim ndng nghidp, thiit bj. 1.BATVANBC Siy khd dam bio chit lupng san phim li qui trinh phuc tap, tidu hao nhidu ning lupng. Ndu vu thu hoach gap thdi tidt khong thuin lpi ning mua that thudng thi san phim sau thu hoach sd bj hong, keo theo cong sue ca mpt mua vat va cua nguoi nong din. Hidn nay say khd ndng san dang hat phan Ion chu ydu li phoi trdn sin dudi inh ning mit trdi. Cic co so siy bang co gidi rit it, do viy khong chu dpng dupe siy khd ndng sin trudc luc cho vio kho bao quan. Dd timg budc dua nginh nong nghidp ldn co khi hda vi tu dong hda thi khdng thd khdng hinh thinh cic cinh dong miu ldn, don didn doi thua. Phin dch sir thit thoit cua cic loai nong san, cic nhi khoa hpc cho ring tuy theo thdi gian thu hoach khac nhau mi ty Id hao hyt cua cic cdng doan trdn cd su khic nhau. Trong cic vy thu hoach ddng xuin ho$c vao mua mua bao ty Id niy la ldn nhat vi gap thdi tidt khdng thuin tidn cic san phim ndng san (chu ydu la lua) khdng dupe siy khd din ddn hu hdng rit nhidu. Trong pham vi bii bio niy chi dd cip ddn kdt qua nghidn cuu thilt bi siy cd kha ning siy dupe cic loai hat chu ylu trong ndng san thyc pham (nhu thde, ngd, ca phd...) mpt cich cd hidu qua vi cd thd trang bi cho cic co sd cd sin lupng vira vi nhd nhim giam bdt sy hao hut ndng san thyc phim hidn nay. ylu su dyng cic logi thilt bj chinh nhu thap say, thidt bj siy vi ngang, him siy, siy thung quay. Cd thd so sinh uu nhupc didm cua cac thidt bj nay qua mdt sd thdng sd nhu sau: 2.1. Thip Thap siy n»-u su dyng loai thap siy dong (hgt chuydn dpng tir trdn xudng) thi thap rat cao. Hd thdng phai cd giu tii chuydn vit lidu vao vi bang tai chuyln vit lidu ra, cd din giio dd che ning mua. Dd cip nhidt cho thip sly phii co ld ddt than vi qugt gid thoi tic nhin vio thip dl say vit lidu. Nhin chung thip siy dupe su dyng d l siy cic logi hgt nhu thde, ngd, diu, c i phd thi cho chit lupng khi tdt vi nang suit ldn. Nhupc diim cua thap say li kinh phi diu tu cao. Niu san lupng nhd thi khdng ndn sir dung vi khdng hidu qui, chi phi cho 1 don vj sin pham cao. L PHAN TiCH LUX CHQNTTiiTBI Trong siy ndng san thuc phim dgng hat nhd nhu thde, ngd, c i phd, d$u... d nude ta hidn nay chu Hinh 1. H thdng siy thip 1. giu tii; 2. bing Hi thio hdu, 3. thip siy, Khoa hda- Dgi hpc Vinh NdNG NGHI$P-VA PHAT lrl6t NONGIHON - K t THANG 2/2014

2 r KHOA HOC CONG NGHfe 22. Thilt b sly vi ngang Diy lei loai may sly tinh. Thilt bj say co nang suit trung binh. Thilt bj c6 ciu tao don gian: xung quanh xay bang g?ch, dudi lat gach hoac bdtong. Cich day khoang mm ngudi ta lap dat m$t vi ngang. Thuc ra vi la ludi 16, vat lilu can sly day khoiing mm. Tac nhan sly dugc quat hut tu 16 ddt (nhi6n lilu cho 16 dot la than hoac go, trlu) thdi vao phia duoi him sly, qua ludi xuydn qua lop h?t dl sly khd hat Trong qua trinh sly cu 34 gia phii dao h?t tu trdn xuong duoi cho vat lilu khd diu. 3 < Hinh 3. Hi thdng sly thung quay (so dd hi thdng sly thi nghiim) 1. quat; 2. dung cu do nhiet lupng; 3. cua; 4. bp truyen banh ring; 5. m it trong thung (luoi); 6. m it ngoai thung (lu&i); 7. dong cor, 8. hop giam tdc Hinh 2. Hi thdng sly giudng 1. ld than; 2. quat; 3. giudng siy; 4. v$tlieu siy Thilt bj sly don gian dl su dung, kinh phi dau tu it song 16p vat lilu sly tinh ndn sly khong diu, muon diu phai mit nhilu cong dao tron rit mit nhgc, thoi gian sly dai. Muon tang nang suit thi phai tang diln tich him sly va do vay phai tang cong suit 16 dot, qu$t cung rit tdn kim va khong hgp ly. Mgt nhugc diim nua cua sly vi la thilt bj chilm diln tich ldn Miy sly thung quay May sly thung quay tir tru6c toi nay chu ylu dugc su dung dl sly lidn tuc nhu: sly duong, chi, mdt sd nong san khic. Day la may sly c6 nhilu uu diim nin chung tdi da nghien cuu thilt kl may sly phu hgp dl sly cac san pham nong san thuc pham sau thu hoach co th6i gian sly dai. So do nguydn ly miy sly thung quay thi nghiim dugc thi hiln a hinh 3. Miy c6 d u tao nhu sau: Thung sly quay gom 2 hinh try ldng vio nhau, mat trong vl ngoai thung diu bing lu6i v6i kich thudc 16 nho hon kich thudc h?t sly. Khoing trdng giua 2 mat trong va ngoii chua v$t lilu sly dugc chia lam 3 ngan dgc theo chilu dii tryc (dl tranh v$t lilu ddn l?ri khi thung quay). Khdng khi sly dugc quat thdi vao giua thung va di xuyln qua ldp h?t xung quanh thung, sly khd h?t vl mang theo Im ra ngoii theo cac lo m$t luoi ngoii. Nguydn ly may sly hat kiiu thung quay nay cd nhilu uu diim: - Trong qua trinh thung quay v$t lilu cd su chuyln dong tuong ddi trong thung, do vay do khd cua vat sly diu hon so vdi sly tinh rit nhilu. Vat lidu trong may sly khdng can dao trgn. - Kich thudc chilm cho cua may nho ggn hon nhilu so vdi thilt bj sly vi ngang va thip hon nhilu so vdi cac loai thap sly. - Sd nhan cdng rit it (chi can 1-2 ngudi van hanh may). - Chi phi may tuy cd cao song thdi gian sly dugc nit ngin (chi khoang 7 gio) tuy thugc vao dg am vat lidu ndn mang lai hidu qua kinh tl cao. Vi du vdi kich thudc duong kinh luoi trong va luoi ngoai cua thung sly < >0,6m va 4>1,8 m, chilu dai thung la 6 m cd thi sly dugc lugng vat lilu la thde hoac ngd 12 tln/me ma gia thanh cua may kl ca 16 than quat chi tridu ddng. - May sly thung quay co nang suit 12 tln/me phu hgp cho cac ca sa sly nguydn lilu cd nang suit trung binh va nho. - May rit thich hop dl sly d c san pham dang hat nhu lua, ngd, d phd, dau... Chit lugng sin phim sly cao. San phim sau sly dugc bang tai, vit tai van chuyln din noi bao quan rit thuan tiln. - Vdi hi thdng thilt bj sly niy vile ca khi hoa tu dong hda dugc thuc hiln dl dang gan nhu toan bg. Tu su phan tich trdn ta co thi kit luan: HI thong sly thung quay su dung cho d c ca sa sly co san lugrng trung binh nha d c uu diim ggn, kha nang ca khi hoa cao, chit lugng san pham sly ddng diu, thdi gian sly ngin. NONG NGHlfP VA PHAT TRlfN NONG THON - KY THANG 2/2014 >31

3 KHOA HQC CONG NGHft thong say thap thich hop cho cac ca sa dau tu say tap trung nang suat lan, ca sd nha xuong, kho chua day du, hien dai, gsn lidn bao quan lau dai cho du tru hosc gan lidn vdi ca sd chd bidn thi rat phu hgp. Thd tich chua vat lieu say V - 0,1414 mj. Vat lieu thiing Inox. Thung quay n - 4 v/p. Dong ca 0,5 kw ; n v/p. Truydn dgng cho thung siy: Dpng ca -> Bp truyen dong banh dai thang - Hgp giam tdc bd truyen banh dai rang hop giam tdc & thung. Thidt bj say vi ngang, tru dung (say cot), say dong tu nhien chi phu hap cho cac ca sd san xuat nho, cac ho gia dinh. 4. NGHBV CUU CONG N Gtf SAY HAT THtN MAY S*Y THUNG 3. TWH TOAN CAC THONG Sti MAY SAY THUNG QUAY TM QUAY VU KET CAU MOI NGHfM 4.1. Phan tich c c thdng sd inh hudng He thong thidt bj gom quat - dung cu do nhiet May say thiing quay da dugc tinh toin thidt kd luong [ bo phan c p nhiet] - thung siy. Trong do chd tao nhu sa do nguyen ly hinh 3. Trong d6 ding nhiet cho qui trinh say thi nghiem la nhiet lupng tir luu y la thung say. Thung say kdt cau gom 2 hinh try dien (trong san xuat sir dung lo dot than). bang ludi < >2 dong tam co dudng kinh +450 va Thong so vat lieu: quay dugc nhd 2 vanh dai va banh rang ldn lap ngoii Ngo hat co: Dp am dau, cuoi Wd» 23%, Wc = 12%. than thiing. Khoing khong gian giua hai try lu6i Khdi lugrng say 1 me G = 98 kg/6,5 gid. He so chua vat lieu siy dugc chia lam 3 khoang (ngan bang chua day <p = 0,9. vach cung theo dgc dudng sinh) dl tranh v$t lieu ddn - Luang am can boc hoi 1 gid lai khi quay (ndu thiing dai va to s chia lam cac W =G W -W =98. 1-W2 1-0, 12 12,4 - Tinh nhiet cho thidt bi siy. Ddi vdi nhiet dp tac nhan say t, = 20 C, t2 = 60 C. Tinh nhiet cho thidt bj say gom: nhiet tdn that ddt nong vat lieu, ddt nong thidt bj, mat mat ra moi trudng xung quanh va tic nhan say mang ra. Da xac dinh duoc nhiet lugng can cho qua trinh Q = kj. - Tinh va chgn quat: Ca sd de tinh chgn quat la nang suat khong khi kho cap cho thi^t bj say va cot ap toan phan. Cot ap toan phan dugc xac dinh theo cong thuc: AP = APC+ AP8+ APd Trong do: APC, AP8, APd - trd luc trang bi cap nhiet (calorifien), trd luc thidt bj say, trd luc khi dong thoat ra mieng quat (mmh20 ). Da xac djnh dugc trd luc cac thanh phan tren: APC- 20 mm H20 ; AP9 = 50 mm H20 ; APd = 20 mm H20. Vay AP = = 90 mm H20. Tir cac sd lieu tinh toan vd nang suat quat, trd luc quat, qua do thj dac tuydn cua quat ta chgn dugc quat co cac thong sd: Q = 500 m3/gid; n = 2900 v /p ; H = 200 mm H20 ; N = 0,6 kw. - Tinh ca khi cho thidt bj say: Chidu dai thung 1000 mm. Dudng kinh ngoai < >450 mm, dudng kinh vanh trong+150 mm. 132 khoang nho han bang them cac vach theo dudng kinh, va luc nay sd cua se nhilu hon phii hgp vdi nang suat thuc cua thidt bj). Cac ydu td khi nghien cuu cdng nghe va thidt bj day du se la: - Phai co md hinh thi nghiem ho$c thidt bj dl nghien cuu, phai xac djnh dung cac ydu td chinh inh hudng ddn qua trinh do la: tdc dd vdng quay cua thiing (lien quan ddn tdc dg dao tron vat lilu), tdc d0 tac nhan say, nhiet do tac nhan siy va he sd chua diy cua thiing. O day chung tdi da chd tao dugc mdt thidt bj hoan chinh dd say ngo co day du quat, trang bj cip nhiet, thiing say vi bg didu chinh nhiet dg, tdc dd thiing va tdc dd tac nhan say. - Tdc dg vong quay cua thimg cu till chgn 2 v/p va 4 v/p. - Tdc dg gio qua ldp vat lidu chgn 0,3 m/giiy li tdc do thich hgp dd siy cic loai hat d cic loai thidt bj say thip, vi ngang, tru dung. - Nhidt dg say ngo chgn 6&C li nhiet dd thich hgp dd siy ngo. - He so chua diy cua thimg chgn <p- 80% vi <p 90%. Phan tich cic ydu td trdn cho thiy ring ngoii thidt bj phii cd dd nghidn cuu (da dupe chd tao) cic ydu td khic inh hudng ddn him muc tidu cua qui trinh li thdi gian siy ngin nhit dd dat chit lupng sin phim siy tdt nhit nhu sau: NdNG NGHlf P VA PHAT TRIEN N6NG TH6N - KY THANG 2/2014

4 KHOA HQC COHO NOHt Tdc do v6ng quay cua thung siy: Tdc do vdng quay cing ldn thi dio tron cang nhilu, nhung toe do quay cua thung khong thi vugt qua toe d0 toi han (la tdc do hat bdm chat vao thung ma khong roi). Co nhu vay hat dupe djch chuyln, thay doi vi tri nhilu hon, tilp xuc vdi tac nhan siy nhilu hon lam im thoit ra nhanh hon va thdi gian siy ngan hon. Mat khic tdc do quay con anh hudng din nang suit vi cong suit cua thilt bi. Thuc nghidm cho thiy siy thung quay toe do 2-5 v/p la phu hgp. Nhidt do siy: Nhi t do siy hoan toan phu thuoc tinh chit cua vat lidu siy. Voi ngo nhi t do cao nhat cho phip cua hat la 50 C ndn chgn nhi t do tac nhan siy GOPCli phu hgp. Van tdc tac nhan siy: Van toe tic nhan siy qua ldp vat li u anh hudng din cong suit quat, luu lugng tic nhan vi lugng nhi t cip cho thilt bj siy. MOt ylu t6 quan trgng can phai xet la ban chit vat li u siy. C6 lo^i vat li u siy can tdc do siy nhanh, c6 loai can tdc do siy cham. Tdc d0 siy anh hudng din do thoat am cua v$t li u vi true tilp anh hudng din chat lugng sin phim sau siy (nhu nut, vd...). Ciu true cua vat li u siy inh hudng din su lidn kit am cua vat li u vi do tinh chit ciu true cua vat lilu quylt dinh din thdi gian siy, phuong phip siy vi chi do siy cua vat lilu. Trong cic thilt bj siy san phim dang hat nhu thde, ngo, ci phi, dd nhu thap siy, siy vi ngang, siy tru dung thi v$n tdc tic nhan siy V = 0,3 m/giay la hgp tyh sd chua day cua thung: Khi vat li u siy chua trong thilt bj chuyln dong thi hi sd chua day quylt dinh nang suit vi thdi gian siy. Niu hi sd chua day nhd thi nang suit nho va do im cua vat lilu sau siy khdng ddng diu vi tac nhan siy se chuyln dong qua khoing khdng gian nio co trd luc it, nhilu hon con cic phin khic it hon giy nin tdn thit nhilt ldn, tuy ring do dio tron cua vit li u ldn (dilu niy thiy rit rd d cic thilt bi siy quay nim ngang). C6n niu h sd chua diy ldn thi ndng suit cao, do im sin pham sau siy diu hon do tic nhin siy di qua ldp vat li u diu hon. DO dao tron vit lilu do dd cung nho hon so vdi trudng hgp cd h sd chua diy nhd. Trong c i hai trudng hgp chung ta cd thi so sinh thdi gian siy cdn cu vao do im san phim cuoi cung. Trudng hgp h sd chua diy nhd (<60%) cd thi khang djnh ring lugng tic nhin tdn thit rit nhilu va thdi gian siy khdng giam bao nhidu. Dl dam bao nang suit va do am cua san pham siy dong diu chung tdi gidi han nghidn cuu h sd chua day la 80% va 90%. 42. Thuc nghidm siy trdn thilt bi Ngoai thilt bj da chi tao dl nghidn cuu chi do siy, cd 4 ylu td chinh anh hudng din qua trinh say hat trdn may say thimg quay dd la: sd vdng quay cua thiing (n, v/p), nhidt do tac nhan siy ( O, h sd chua day cua vat lidu (<p, %) va tdc do tac nhan say qua ldp vat lidu (V, m/s). Dl don gian cho qua trinh thuc nghiem, chung tdi khdng chi 2 thong sd khong thay ddi trong qua trinh siy, dd la: Nhidt do tac nhan siy - la nhi t do tac nhan siy tdi da cho phep say vat lidu (t = 60 C) va tdc do tac nhan say di qua ldp vat li u (V = 0,3 m/s). Tiln hanh 4 thi nghidm cho 4 bo thong sd: - Thi nghidm thu nhit: tm = 60 C; Vta - 0,3 m/giay; n, * 2 v/p; cp= 80%. - Thi nghidm thu hai: t^ * 60 C; V, - 0,3 m/giay; n, = 2 v/p; cp = 90%. - Thi nghidm thu ba: t^ - 60PC; Vta * 0,3 m/giay; n,/ 4 v/p; <p= 80%. - Th: nghidm thu tu: t, = 60 C; Vta * 0,3 m/giay; n, 4 v/p; <p= 90%. Tir cac thi nghidm nay ta xac dinh dugc chdnh ldch do am cua vat lidu siy phia mat trong (tilp giap vdi khdng khi trdi) va ham muc tidu cua qua trinh la thdi gian say (xj dl dat dugc chdnh l ch do am cua vat say theo ydu ciu li nhd nhit Cic kit qui thi nghidm dugc dua ra d bang dudi day: TT Cdc thong sd thi nghidm i 1 t* = 6tf»C; Vm= 0,3 m/gidy; n, = 2 v/p; (p = 80%. DOim cua vat lidu mdt trong (WJ% Dq im cua vdt lidu mdt ngodi (WJ% Thdi gian siy (z j 12,5 13,0 7hlV 12,6 13,2 7h20* 12,2 12,6 6h45 12,3 12,8 6h58 t* = 60PC; V* = 2 3 0,3 m/gi&y; n, = 2 v/p; <p= 90%. t. = 60PC-, V* = 0,3 m/gidy, nt = 4 v/p; <p= 80%. 4 t. = 60^C; Ym= 0,3m/gidy; n, = 4 v/p; <p= 90% N0NGNGHliP VAPHATH» n N 6 N G TH 6 n -K Y TH A N G 2/

5 KHOA HQCC6NG NG HI Kit qua say thuc nghidm trdn cho thay: - Chdnh ldch am cua vat lieu mat trong (mat tilp xuc voi tac nhan say) va mat ngoai (mat tiep xuc voi khong kho khong Ion, chi 0,4-0,8% (a thi nghi m 3 va thi nghi m 2). - Chdnh ldch am vdi cac thong so say n = 4 v/p va cp = 80% la 0,4% va d n = 4 v /p va cp = 90% la 0,5% la khong nhilu, nhung voi cp = 90% nang suat dat dugc sd cao hon. - H so chua day 80% va 90% khong anh huong nhilu tdi toe dg tac nhan say di qua lop vat li u (thi hi n d su chdnh l ch im cua vat lilu). - Thoi gian say a c&c toe do n = 2 v /p va n = 4 v/p chi chdnh Ion nhat 25 phut d ch i do n = 4 v/p; cp = 80% va n = 2 v/p; cp = 80%. Ridng d chd do n = 4 v/p; cp = 80% va cp = 90% thdi gian say chi ldch 13 phut Can cu vao nang suat, do am dong diu thi ch i do say n = 4 v/p; cp = 90%; V = 0,3 m/giay; 1^,= 60 C sd cho ta cac kit qua tot vi nang suat say d ch i do nay la Ion nhat, do am chi l ch 0,5% va thdi gian say chi dai hon 13 phut so vdi ch i dg say thi nghi m K ft LUAN VA KlfN IMGH D l nghidn cuu cong ngh say nong san dang hat tren may say thung quay, da nghidn cuu tinh toan, thilt k l va ch i tao dugc mot may say thung quay hoan chinh bao gom: quat - trang bi cap nhi t (calorifer) - thung quay - h i truyln dong va h i didn dilu khiln cho may say. May hoat dpng <5n djnh, dam bao cac thong so dl ra trong qua trinh nghiln cuu. Da tim ra dugc chi dg siy h$t thich hgp nhit vdi cac thong so: Toe dg tac nhan siy V - 0,3 m/giay; toe dp quay cua thung n - 4 v/p va do chua day san pham cua thung cp - 90%. Vdi cac thong so trdn san pham siy co do dong diu cao vi nang suat cao. May co thi say dugc nhilu loai nong san thyc pham dang hat nhu: th6c, ngo, ca phi, dau... vdi chit lugrng tot May say loai nay ggn, dl dilu khiln, v6n dau tu khong ldn va dl ca khi hoa trong cdng nghidp. Day la may siy co kit ciu thich hgp, mgt d«uig may mdi, dl nghi dugc triln khai vao san xuit TAI Uftl THAM KHAO 1. Trinh Chat - Ca sa thiit ks may va chi ti6t m ay- NXBKHKT Nguyln Trgng Hi p - Chi tifr may Tl,2 NXB Bg DH&THCN Tran Van Phu - Tinh todn thiit k i h i thdng say- NXBGD Tran Van Phu - LI Nguyln Duong - Ky thu$t say nong san- NXBKHKT HN Bg NN&PTNT - Mdy siy h at- NXBNN RESEARCH ON DESIGN, MANUFACTURING AND DRYING TECHNOLOGY SOME GRANULAR AGRICULTURAL PRODUCTS ON THE ROTARY DRUM DRYER Nguyen Tan Thanh Summary Research topic 'Technology research on drying agricultural on the rotary drum dryer'' has obtained results: Has designed, manufactured one complete rotary drum dryer at laboratorial scale. Machine consists of main parts: fan, calorimeter, rotary drum, actuatorand control system automatic temperature for machine. Rotary drum made of two coaxial pillar grid, between contains materials, the space inside where drying agent into and drying materials. Research on grain drying on these accessories find that moisture of the after drying material is evenly flayer grain inner and outer only vary %). The fill of material is 90%, and rotational speed of thebarrel n = 4 rpm, speed of drying agent through the grain u = 0.3 m /s gives better results in productivity and quality. Rotary drum dryer may be drying some granular agricultural products such as rice, com, coffee, beans...this devices compact, easy to make, easy to operate, moderate cost, appropriate for the average productivity establishments. Using rotary drum dryer to dry the product of grain will give high efficiency. Keywords: Rotarydrum dryer, agriculturalproducts, drying, accessories. Ngudi phin bi n: GS.TSKH. Ph^m Van Lang Ngiy nhin bii: 25/11/2013 Ngiy thdng qua phin bi n: 26/12/2013 Ngiy duy t dang: 03/01/ NONG NGHIEP VA PHAT TRIEN NdNG TH6N - KY THANG 2/2014

KHI X L T SÔNG H NG VÀO SÔNG ÁY

XÂY D NG B N NG P L T KHU V C H DU TÓM T T T KHI X L T SÔNG H NG VÀO SÔNG ÁY Lê Vi t S n 1 Bài báo này trình bày k t qu nghiên c u, ánh giá r i ro ng p l vùng h du sông áy khi x l t sông H ng vào sông