{"id":8667,"date":"2009-03-24T03:13:32","date_gmt":"2009-03-23T20:13:32","guid":{"rendered":"http:\/\/vafs.gov.vn\/vn\/2009\/03\/nghien-cuu-anh-huong-cua-ap-xuat-ep-bien-va-chieu-day-thanh-tre-luong-den-do-ho-mach-keo-cua-van-ghep-thanh-tre-luong\/"},"modified":"2019-09-25T10:00:41","modified_gmt":"2019-09-25T03:00:41","slug":"nghien-cuu-anh-huong-cua-ap-xuat-ep-bien-va-chieu-day-thanh-tre-luong-den-do-ho-mach-keo-cua-van-ghep-thanh-tre-luong","status":"publish","type":"post","link":"https:\/\/vafs.gov.vn\/vn\/nghien-cuu-anh-huong-cua-ap-xuat-ep-bien-va-chieu-day-thanh-tre-luong-den-do-ho-mach-keo-cua-van-ghep-thanh-tre-luong\/","title":{"rendered":"Nghi\u00ean c\u1ee9u \u1ea3nh h\u01b0\u1edfng c\u1ee7a \u00e1p xu\u1ea5t \u00e9p bi\u00ean v\u00e0 chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng \u0111\u1ebfn \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gh\u00e9p thanh tre lu\u1ed3ng"},"content":{"rendered":"

B\u00f9i Ch\u00ed Ki\u00ean<\/em><\/strong><\/p>\n

Vi\u1ec7n Khoa h\u1ecdc L\u00e2m nghi\u1ec7p Vi\u1ec7t Nam<\/h1>\n

Vi\u1ec7t Nam c\u00f3 \u0111\u1eb7c \u0111i\u1ec3m kh\u00ed h\u1eadu, \u0111\u1ea5t \u0111ai . . . r\u1ea5t ph\u00f9 h\u1ee3p cho tre lu\u1ed3ng sinh tr\u01b0\u1edfng v\u00e0 ph\u00e1t tri\u1ec3n. T\u1eeb m\u1ed9t c\u00e2y m\u0103ng sau 3 th\u00e1ng \u0111\u00e3 c\u00f3 m\u1ed9t c\u00e2y tre tr\u01b0\u1edfng th\u00e0nh, ch\u1ec9 3 \u0111\u1ebfn 4 n\u0103m \u0111\u00e3 c\u00f3 th\u1ec3 khai th\u00e1c v\u00e0 s\u1eed d\u1ee5ng. C\u0103n c\u1ee9 v\u00e0o \u0111\u1ed9 tu\u1ed5i ng\u01b0\u1eddi ta x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c \u0111\u1eb7c t\u00ednh c\u1ee7a t\u1eebng \u0111\u1ed9 tu\u1ed5i:<\/p>\n

– Tre lu\u1ed3ng t\u1eeb 2 \u0111\u1ebfn 3 tu\u1ed5i l\u00e0 tre b\u00e1nh t\u1ebb, th\u01b0\u1eddng s\u1eed d\u1ee5ng s\u1ea3n xu\u1ea5t gi\u1ea5y.<\/p>\n

– Tre lu\u1ed3ng t\u1eeb 3 \u0111\u1ebfn 6 tu\u1ed5i l\u00e0 tre gi\u00e0, d\u00f9ng l\u00e0m v\u1eadt li\u1ec7u x\u00e2y d\u1ef1ng, \u0111\u1ed3 m\u1ed9c, \u0111\u1ed3 m\u1ef9 ngh\u1ec7, s\u1ea3n xu\u1ea5t v\u00e1n nh\u00e2n t\u1ea1o . . .<\/p>\n

Hi\u1ec7n nay s\u1eed d\u1ee5ng tre lu\u1ed3ng l\u00e0m nguy\u00ean li\u1ec7u trong c\u00f4ng nghi\u1ec7p s\u1ea3n xu\u1ea5t v\u00e1n nh\u00e2n t\u1ea1o l\u00e0 m\u1ed9t trong nh\u1eefng m\u1ee5c ti\u00eau ch\u00ednh c\u1ee7a ng\u00e0nh c\u00f4ng nghi\u1ec7p ch\u1ebf bi\u1ebfn l\u00e2m s\u1ea3n, \u0111\u1eb7c \u0111i\u1ec3m n\u1ed5i b\u1eadt c\u1ee7a tre lu\u1ed3ng l\u00e0 chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng gi\u1ea3m t\u1eeb g\u1ed1c \u0111\u1ebfn ng\u1ecdn, b\u00ean c\u1ea1nh \u0111\u00f3 c\u00f2n \u0111\u1ed9 cong, \u0111\u1ed9 th\u00f3t ng\u1ecdn. Tre lu\u1ed3ng th\u01b0\u1eddng cong theo m\u1ed9t chi\u1ec1u, \u0111\u1ed9 cong, \u0111\u1ed9 th\u00f3t ng\u1ecdn th\u01b0\u1eddng t\u1eadp trung \u1edf ph\u1ea7n ng\u1ecdn, ph\u1ea7n ng\u1ecdn c\u00e2y chi\u1ec1u d\u00e0y th\u01b0\u1eddng nh\u1ecf n\u00ean khi s\u1eed d\u1ee5ng th\u01b0\u1eddng lo\u1ea1i b\u1ecf ph\u1ea7n n\u00e0y.<\/p>\n

Tre lu\u1ed3ng th\u01b0\u1eddng b\u1ecb m\u1eafc c\u00e1c b\u1ec7nh sau:<\/p>\n

+ Tre lu\u1ed3ng b\u1ecb c\u1ee5t ng\u1ecdn: Do t\u00e1c \u0111\u1ed9ng c\u1ee7a m\u01b0a gi\u00f3 hay m\u1ed9t l\u00fd do t\u1ef1 nhi\u00ean n\u00e0o \u0111\u00f3 m\u00e0 tre lu\u1ed3ng b\u1ecb c\u1ee5t ng\u1ecdn trong qu\u00e1 tr\u00ecnh sinh tr\u01b0\u1edfng, nh\u1ea5t l\u00e0 th\u1eddi k\u1ef3 t\u1eeb m\u0103ng \u0111\u1ebfn tre tr\u01b0\u1edfng th\u00e0nh. \u0110i\u1ec1u n\u00e0y l\u00e0m cho s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a c\u00e2y b\u1ecb thay \u0111\u1ed5i, c\u00e1c t\u00ednh ch\u1ea5t c\u01a1 – v\u1eadt l\u00fd thay \u0111\u1ed5i, tre gi\u00f2n v\u00e0 kh\u1ea3 n\u0103ng ch\u1ecbu l\u1ef1c k\u00e9m.<\/p>\n

+ Tre lu\u1ed3ng b\u1ecb ki\u1ebfn \u0111\u1ee5c: Tre lu\u1ed3ng khi \u0111ang ph\u00e1t tri\u1ec3n c\u0169ng nh\u01b0 sau khi ch\u1eb7t h\u1ea1 th\u01b0\u1eddng b\u1ecb s\u00e2u n\u1ea5m ph\u00e1 h\u1ea1i, do trong th\u00e2n c\u00e2y c\u00f3 m\u1ed9t h\u00e0m l\u01b0\u1ee3ng \u0111\u01b0\u1eddng kh\u00f4ng nh\u1ecf r\u1ea5t h\u1ea5p d\u1eabn v\u1edbi c\u00f4n tr\u00f9ng v\u00e0 n\u1ea5m m\u1ed1c. B\u1ec7nh n\u00e0y th\u01b0\u1eddng xu\u1ea5t hi\u1ec7n khi c\u00e2y c\u00f2n s\u1ed1ng, ph\u1ea7n b\u1ecb b\u1ec7nh s\u1ebd b\u1ecb bi\u1ebfn m\u00e0u v\u00e0 b\u1ecb thay \u0111\u1ed5i c\u00e1c t\u00ednh ch\u1ea5t c\u01a1 – l\u00fd, sau khi ch\u1eb7t h\u1ea1 n\u1ebfu kh\u00f4ng \u0111\u01b0\u1ee3c b\u1ea3o qu\u1ea3n s\u1ebd d\u1ec5 b\u1ecb n\u1ea5m m\u1ed1c ho\u1eb7c m\u1ed1i m\u1ecdt ph\u00e1 h\u1ea1i r\u1ea5t nhanh, l\u00e0m gi\u1ea3m ho\u1eb7c m\u1ea5t kh\u1ea3 n\u0103ng s\u1eed d\u1ee5ng c\u1ee7a tre lu\u1ed3ng.<\/p>\n

+ Tre lu\u1ed3ng b\u1ecb b\u1ec7nh khuy: \u0110\u00e2y l\u00e0 lo\u1ea1i b\u1ec7nh m\u00e0 tre lu\u1ed3ng th\u01b0\u1eddng hay m\u1eafc ph\u1ea3i, theo Phan \u0110\u1ee9c Thu\u1ed9i, L\u00ea Xu\u00e2n T\u00ecnh th\u00ec lo\u1ea1i b\u1ec7nh n\u00e0y r\u1ea5t d\u1ec5 l\u00e2y lan v\u00e0 \u1ea3nh h\u01b0\u1edfng l\u1edbn t\u1edbi c\u00e1c t\u00ednh ch\u1ea5t c\u01a1 – l\u00fd c\u1ee7a tre lu\u1ed3ng.<\/p>\n

1. V\u1eadt li\u1ec7u v\u00e0 ph\u01b0\u01a1ng ph\u00e1p nghi\u00ean c\u1ee9u<\/strong><\/p>\n

T\u1eeb nh\u1eefng \u0111\u1eb7c \u0111i\u1ec3m tr\u00ean th\u00ec nguy\u00ean li\u1ec7u \u0111\u1ec3 s\u1ea3n xu\u1ea5t v\u00e1n gh\u00e9p thanh ph\u1ea3i c\u00f3 \u0111\u1ed9 tu\u1ed5i t\u1eeb 3 n\u0103m tr\u1edf l\u00ean, lo\u1ea1i b\u1ecf ph\u1ea7n ng\u1ecdn v\u00e0 nh\u1eefng c\u00e2y \u0111\u00e3 m\u1eafc b\u1ec7nh. \u0110\u1ec3 x\u00e1c \u0111\u1ecbnh \u1ea3nh h\u01b0\u1edfng c\u1ee7a \u00e1p su\u1ea5t \u00e9p bi\u00ean v\u00e0 chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng \u0111\u1ebfn \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gh\u00e9p thanh ch\u00fang t\u00f4i c\u1ed1 \u0111\u1ecbnh c\u00e1c y\u1ebfu t\u1ed1 sau:<\/p>\n

– \u0110\u1ed9 tu\u1ed5i c\u1ee7a tre lu\u1ed3ng.<\/p>\n

– V\u1ecb tr\u00ed l\u1ea5y m\u1eabu (g\u1ed1c, th\u00e2n).<\/p>\n

– \u0110\u1ed9 \u1ea9m c\u1ee7a thanh tre lu\u1ed3ng tr\u01b0\u1edbc khi \u00e9p v\u00e1n (8%).<\/p>\n

– Kh\u1ed1i l\u01b0\u1ee3ng th\u1ec3 t\u00edch c\u1ee7a v\u00e1n (8g\/cm3<\/sup>).<\/p>\n

– S\u1ed1 l\u1edbp v\u00e1n(3 l\u1edbp), chi\u1ec1u d\u00e0y 15mm.<\/p>\n

– T\u1ef7 l\u1ec7 k\u1ebft c\u1ea5u c\u1ee7a v\u00e1n (1-1-1).<\/p>\n

– Ch\u1ea5t k\u1ebft d\u00ednh: Keo n\u01b0\u1edbc nh\u1eadp t\u1eeb Trung Qu\u1ed1c v\u1edbi c\u00e1c th\u00f4ng s\u1ed1 sau<\/p>\n

+ M\u00e0u s\u1eafc: Tr\u1eafng s\u1eefa<\/p>\n

+ H\u00e0m l\u01b0\u1ee3ng kh\u00f4: 67%<\/p>\n

+ \u0110\u1ed9 nh\u1edbt theo Bz4 (\u1edf 250<\/sup> C): 60 gi\u00e2y<\/p>\n

+ \u0110\u1ed9 PH b\u1ea3o qu\u1ea3n: 8<\/p>\n

+ \u0110\u1ed9 PH khi \u0111\u00f3ng r\u1eafn: 6<\/p>\n

+ L\u01b0\u1ee3ng keo s\u1eed d\u1ee5ng: 1,0 kg\/m2<\/sup> s\u1ea3n ph\u1ea9m<\/p>\n

+ Ph\u01b0\u01a1ng ph\u00e1p \u00e9p: kh\u00f4 – nhi\u1ec7t<\/p>\n

+ \u00e1p su\u1ea5t \u00e9p ch\u00ednh max: 18 kg\/cm2<\/sup><\/p>\n

+ Nhi\u1ec7t \u0111\u1ed9 \u00e9p: 130o<\/sup> C<\/p>\n

+Th\u1eddi gian \u00e9p: 11 ph\u00fat 00 gi\u00e2y<\/p>\n

+ S\u1ea3n ph\u1ea9m \u0111\u1ea1t ti\u00eau chu\u1ea9n Qu\u1ed1c t\u1ebf SGS, ph\u1ee5c v\u1ee5 trang tr\u00ed n\u1ed9i th\u1ea5t, s\u00e0n nh\u1ea3y, s\u00e0n thi \u0111\u1ea5u th\u1ec3 thao . . .<\/p>\n

2. N\u1ed9i dung nghi\u00ean c\u1ee9u<\/strong><\/p>\n

a. X\u00e1c \u0111\u1ecbnh \u1ea3nh h\u01b0\u1edfng chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng \u0111\u1ebfn \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n<\/em><\/p>\n

Chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng c\u00f3 \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn m\u1eadt \u0111\u1ed9 b\u00f3 m\u1ea1ch trong t\u1eebng thanh khi gia c\u00f4ng, c\u00e1ch gh\u00e9p c\u00e1c thanh trong c\u00f9ng m\u1ed9t l\u1edbp v\u00e0 gi\u1eefa c\u00e1c l\u1edbp v\u1edbi nhau, \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn kh\u1ea3 n\u0103ng li\u00ean k\u1ebft gi\u1eefa c\u00e1c thanh c\u0169ng nh\u01b0 l\u00e0m thay \u0111\u1ed5i t\u00ednh ch\u1ea5t c\u1ee7a t\u1eebng thanh d\u1eabn \u0111\u1ebfn t\u00ednh ch\u1ea5t c\u1ee7a v\u00e1n thay \u0111\u1ed5i. \u0110\u1ed9 h\u1edf m\u1ea1ch keo l\u00e0 m\u1ed9t h\u00e0m s\u1ed1 ph\u1ee5 thu\u1ed9c v\u00e0o chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng, b\u1eb1ng th\u1ef1c nghi\u1ec7m ch\u00fang t\u00f4i \u0111\u00e3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c \u1ea3nh h\u01b0\u1edfng c\u1ee7a chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng \u0111\u1ebfn \u0111\u1ed9 h\u1edf m\u1ea1ch keo theo b\u1ea3ng sau:<\/p>\n\n\n\n\n\n\n\n
\u0110\u1ed9h\u1edf(%)<\/strong><\/p>\n

Chi\u1ec1u d\u00e0y(mm)<\/strong><\/td>\n

\u0110\u1ed9 h\u1edf trung b\u00ecnh<\/strong><\/td>\ns\u1ed1 m\u1eabu<\/strong><\/td>\n<\/tr>\n
6.5 – 8.5<\/td>\n25,18<\/td>\n30<\/td>\n<\/tr>\n
8.5 – 10.5<\/td>\n19,68<\/td>\n30<\/td>\n<\/tr>\n
10.5 – 12.5<\/td>\n18,68<\/td>\n30<\/td>\n<\/tr>\n
12.5 – 14.5<\/td>\n16,05<\/td>\n30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

T\u1eeb k\u1ebft qu\u1ea3 th\u1ef1c nghi\u1ec7m, x\u1eed l\u00fd s\u1ed1 li\u1ec7u theo ph\u01b0\u01a1ng ph\u00e1p th\u1ed1ng k\u00ea to\u00e1n h\u1ecdc tr\u00ean m\u00e1y t\u00ednh ch\u00fang ta bi\u1ebft \u0111\u01b0\u1ee3c quan h\u1ec7 gi\u1eefa \u0111\u1ed9 h\u1edf m\u1ea1ch keo v\u00e0 chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng theo ph\u01b0\u01a1ng tr\u00ecnh sau:<\/p>\n

Y = 95.79 + 2.73X – 102.59lgX<\/p>\n

H\u1ec7 s\u1ed1 t\u01b0\u01a1ng quan R = 0.98<\/p>\n

Trong \u0111\u00f3: Y: l\u00e0 \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n<\/p>\n

X: l\u00e0 c\u1ea5p chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng<\/p>\n

\u0110\u1ed3 th\u1ecb quan h\u1ec7 \u0111\u1ed9 h\u1edf m\u1ea1ch keo theo chi\u1ec1u d\u00e0y<\/em><\/strong><\/p>\n

Y(%)<\/p>\n

25<\/p>\n

20<\/p>\n

15<\/p>\n

10<\/p>\n

5<\/p>\n

X(mm)<\/p>\n

8 10 12 14 14.5<\/p>\n

Nh\u01b0 v\u1eady, khi chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng t\u0103ng th\u00ec \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gi\u1ea3m xu\u1ed1ng \u0111\u00f3 l\u00e0 do \u0111\u1eb7c \u0111i\u1ec3m c\u1ea5u t\u1ea1o, tre lu\u1ed3ng c\u00f3 m\u1eadt \u0111\u1ed9 b\u00f3 m\u1ea1ch t\u0103ng d\u1ea7n t\u1eeb trong ra ngo\u00e0i theo ph\u01b0\u01a1ng xuy\u00ean t\u00e2m v\u00e0 t\u0103ng d\u1ea7n t\u1eeb g\u1ed1c \u0111\u1ebfn ng\u1ecdn theo ph\u01b0\u01a1ng chi\u1ec1u cao th\u00e2n c\u00e2y, n\u00ean t\u00ednh ch\u1ea5t c\u01a1 h\u1ecdc t\u1ea1i c\u00e1c \u0111i\u1ec3m l\u00e0 kh\u00e1c nhau. Khi k\u00edch th\u01b0\u1edbc thanh gia c\u00f4ng c\u1ed1 \u0111\u1ecbnh, chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng t\u0103ng th\u00ec ch\u00eanh l\u1ec7ch m\u1eadt \u0111\u1ed9 b\u00f3 m\u1ea1ch gi\u1eefa ph\u1ea7n c\u1eadt v\u00e0 ru\u1ed9t c\u1ee7a thanh gia c\u00f4ng gi\u1ea3m, t\u1ee9c m\u1eadt \u0111\u1ed9 b\u00f3 m\u1ea1ch trong thanh gia c\u00f4ng \u0111\u1ed3ng \u0111\u1ec1u h\u01a1n. Do v\u1eady, khi \u00e9p v\u00e1n d\u01b0\u1edbi t\u00e1c d\u1ee5ng c\u1ee7a nhi\u1ec7t \u0111\u1ed9 v\u00e0 \u00e1p su\u1ea5t th\u00ec ch\u00eanh l\u1ec7ch co ng\u00f3t khi \u00e9p gi\u1eefa hai b\u1ec1 m\u1eb7t c\u1ee7a thanh gi\u1ea3m, \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gi\u1ea3m khi chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng t\u0103ng, t\u1ea1o v\u00e1n c\u00f3 ch\u1ea5t l\u01b0\u1ee3ng t\u1ed1t h\u01a1n.<\/p>\n

b. X\u00e1c \u0111\u1ecbnh \u1ea3nh h\u01b0\u1edfng \u0111\u1ed9 h\u1edf m\u1ea1ch keo theo \u00e1p su\u1ea5t \u00e9p bi\u00ean<\/em><\/p>\n

\u00e1psu\u1ea5t \u00e9p bi\u00ean nh\u1eb1m t\u1ea1o ra s\u1ef1 ti\u1ebfp x\u00fac gi\u1eefa c\u00e1c thanh tre lu\u1ed3ng v\u1edbi nhau \u0111\u01b0\u1ee3c t\u1ed1t h\u01a1n, \u0111\u1ed3ng th\u1eddi t\u1ea1o cho m\u00e0ng keo m\u1ecfng, \u0111\u1ec1u, li\u00ean t\u1ee5c v\u00e0 l\u00e0m c\u00e1c thanh k\u1ebft d\u00ednh l\u1ea1i v\u1edbi nhau.<\/p>\n

B\u1eb1ng th\u1ef1c nghi\u1ec7m, ch\u00fang t\u00f4i x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c \u1ea3nh h\u01b0\u1edfng c\u1ee7a \u00e1p su\u1ea5t \u00e9p bi\u00ean P \u0111\u1ebfn \u0111\u1ed9 h\u1edf m\u1ea1ch keo theo b\u1ea3ng sau:<\/p>\n\n\n\n\n\n\n\n
\u0110\u1ed9 h\u1edf (%)<\/strong><\/p>\n

P \u00e9p bi\u00ean(kg\/cm2<\/sup>)<\/strong><\/td>\n

\u0110\u1ed9 h\u1edf trung b\u00ecnh<\/strong><\/td>\ns\u1ed1 m\u1eabu<\/strong><\/td>\n<\/tr>\n
5<\/td>\n22<\/td>\n30<\/td>\n<\/tr>\n
5.5<\/td>\n15,23<\/td>\n30<\/td>\n<\/tr>\n
6<\/td>\n11,64<\/td>\n30<\/td>\n<\/tr>\n
7<\/td>\n8,36<\/td>\n30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

T\u1eeb k\u1ebft qu\u1ea3 th\u1ef1c nghi\u1ec7m, x\u1eed l\u00fd s\u1ed1 li\u1ec7u b\u1eb1ng ph\u01b0\u01a1ng ph\u00e1p th\u1ed1ng k\u00ea tr\u00ean m\u00e1y t\u00ednh cho ch\u00fang ta quan h\u1ec7 gi\u1eefa \u0111\u1ed9 h\u1edf m\u1ea1ch keo v\u00e0 \u00e1p su\u1ea5t \u00e9p bi\u00ean theo ph\u01b0\u01a1ng tr\u00ecnh sau:<\/p>\n

Y = 260.3 + 38.08X – 613.5lgX<\/p>\n

H\u1ec7 s\u1ed1 t\u01b0\u01a1ng quan R = 0.99<\/p>\n

Trong \u0111\u00f3: Y: L\u00e0 \u0111\u1ed9 h\u1edf m\u1ea1ch keo<\/p>\n

X: L\u00e0 \u00e1p xu\u1ea5t \u00e9p bi\u00ean<\/p>\n

\u0110\u1ed3 th\u1ecb quan h\u1ec7 \u0111\u1ed9 h\u1edf m\u1ea1ch keo theo \u00e1p su\u1ea5t \u00e9p bi\u00ean<\/em><\/strong><\/p>\n

Y(%)<\/p>\n

25<\/p>\n

20<\/p>\n

15<\/p>\n

10<\/p>\n

5<\/p>\n

X(kg\/cm2<\/sup>)<\/p>\n

2 4 6 7<\/p>\n

Khi \u00e1p su\u1ea5t \u00e9p bi\u00ean t\u0103ng th\u00ec \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gi\u1ea3m xu\u1ed1ng, \u0111\u00f3 l\u00e0 do tre lu\u1ed3ng c\u00f3 \u1ee9ng su\u1ea5t t\u00e1ch ngang r\u1ea5t nh\u1ecf, n\u00ean khi x\u1ebb thanh kh\u00f4ng bao gi\u1edd c\u1ea1nh x\u1ebb l\u00e0 m\u1ed9t \u0111\u01b0\u1eddng th\u1eb3ng, \u0111\u1ed3ng th\u1eddi gi\u1eefa c\u00e1c l\u00f3ng c\u1ee7a tre lu\u1ed3ng c\u00f2n c\u00f3 c\u00e1c \u0111\u1ed1t, ph\u1ea7n n\u00e0y c\u00f3 c\u00e1c b\u00f3 m\u1ea1ch s\u1eafp x\u1ebfp kh\u00f4ng theo quy lu\u1eadt, b\u00f3 m\u1ea1ch ph\u1ea7n n\u00e0y nhi\u1ec1u h\u01a1n ph\u1ea7n l\u00f3ng n\u00ean ph\u1ea7n \u0111\u1ed1t th\u01b0\u1eddng c\u1ee9ng ch\u1eafc v\u00e0 gi\u00f2n. Khi ch\u00fang ta \u00e9p v\u00e1n th\u01b0\u1eddng x\u1ea3y ra ba tr\u01b0\u1eddng h\u1ee3p ti\u1ebfp x\u00fac theo th\u1ee9 t\u1ef1 sau:<\/p>\n

1. M\u1eaft ti\u1ebfp x\u00fac v\u1edbi m\u1eaft<\/p>\n

2. L\u00f3ng ti\u1ebfp x\u00fac v\u1edbi m\u1eaft<\/p>\n

3. L\u00f3ng ti\u1ebfp x\u00fac v\u1edbi l\u00f3ng<\/p>\n

D\u01b0\u1edbi t\u00e1c d\u1ee5ng c\u1ee7a nhi\u1ec7t \u0111\u1ed9, \u00e1p su\u1ea5t c\u00e1c thanh gh\u00e9p \u0111\u01b0\u1ee3c ho\u00e1 m\u1ec1m l\u00e0m c\u00e1c b\u00f3 m\u1ea1ch bi\u1ebfn d\u1ea1ng d\u1ebbo v\u00e0 x\u00edch l\u1ea1i g\u1ea7n nhau h\u01a1n m\u00e0 kh\u00f4ng b\u1ecb ph\u00e1 h\u1ee7y. V\u1eady \u00e1p xu\u1ea5t \u00e9p bi\u00ean ph\u1ea3i \u0111\u1ee7 l\u1edbn \u0111\u1ec3 b\u1ec1 m\u1eb7t ti\u1ebfp x\u00fac g\u1eefa c\u00e1c thanh l\u00e0 t\u1ed1t nh\u1ea5t, nh\u01b0ng \u00e1p su\u1ea5t \u00e9p bi\u00ean ph\u1ea3i nh\u1ecf h\u01a1n \u1ee9ng su\u1ea5t \u00e9p ngang c\u1ee7a tre lu\u1ed3ng \u0111\u1ec3 v\u00e1n kh\u00f4ng b\u1ecb ph\u00e1 hu\u1ef7.<\/p>\n

K\u1ebft lu\u1eadn<\/strong><\/p>\n

Qua qu\u00e1 tr\u00ecnh nghi\u00ean c\u1ee9u th\u1ef1c nghi\u1ec7m, ki\u1ec3m tra t\u00ednh to\u00e1n \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gh\u00e9p thanh tre lu\u1ed3ng ch\u00fang t\u00f4i th\u1ea5y r\u1eb1ng:<\/p>\n

+ Khi chi\u1ec1u d\u00e0y th\u00e0nh tre lu\u1ed3ng t\u0103ng th\u00ec \u0111\u1ed9 h\u1edf m\u1ea1ch keo c\u1ee7a v\u00e1n gi\u1ea3m xu\u1ed1ng, ch\u1ea5t l\u01b0\u1ee3ng v\u00e1n t\u0103ng l\u00ean.<\/p>\n

+ Khi t\u0103ng \u00e1p xu\u1ea5t \u00e9p bi\u00ean \u0111\u1ed9 h\u1edf m\u1ea1ch keo gi\u1ea3m, tuy nhi\u00ean \u00e1p xu\u1ea5t \u00e9p bi\u00ean kh\u00f4ng \u0111\u01b0\u1ee3c v\u01b0\u1ee3t qu\u00e1 \u1ee9ng su\u1ea5t \u00e9p ngang c\u1ee7a tre lu\u1ed3ng.<\/p>\n

Khi s\u1ea3n xu\u1ea5t, \u0111\u1ec3 v\u00e1n s\u1ea3n ph\u1ea9m c\u00f3 \u0111\u1ed9 h\u1edf m\u1ea1ch keo nh\u1ecf nh\u1ea5t, ch\u1ea5t l\u01b0\u1ee3ng v\u00e1n t\u1ed1t nh\u1ea5t th\u00ec n\u00ean \u00e9p v\u00e1n theo ch\u1ebf \u0111\u1ed9 \u00e9p sau:<\/p>\n

+ \u00e1psu\u1ea5t \u00e9p ch\u00ednh max: 18 kg\/cm2<\/sup><\/p>\n

+ \u00e1psu\u1ea5t \u00e9p bi\u00ean max: 6.5 kg\/cm2<\/sup><\/p>\n

+ Nhi\u1ec7t \u0111\u1ed9 \u00e9p: 1300<\/sup> C<\/p>\n

+ Th\u1eddi gian \u00e9p: 11 ph\u00fat<\/p>\n

T\u00e0i li\u1ec7u tham kh\u1ea3o<\/strong><\/p>\n

– Ph\u1ea1m V\u0103n Ch\u01b0\u01a1ng – Tr\u1ea7n Ng\u1ecdc thi\u1ec7p – Nguy\u1ec5n V\u0103n Thu\u1eadn, C\u00f4ng ngh\u1ec7 s\u1ea3n xu\u1ea5t v\u00e1n nh\u00e2n t\u1ea1o<\/em>, \u0110\u1ea1i h\u1ecdc L\u00e2m nghi\u1ec7p, 1993.<\/p>\n

– Nguy\u1ec5n V\u0103n Thu\u1eadn, Keo d\u00e1n g\u1ed7, 1994.<\/p>\n

– L\u00ea Xu\u00e2n T\u00ecnh- Nguy\u1ec5n \u0110\u00ecnh H\u01b0ng, Nguy\u1ec5n Xu\u00e2n Khu L\u00e2m s\u1ea3n v\u00e0 b\u1ea3o qu\u1ea3n l\u00e2m s\u1ea3n.<\/p>\n

– Tr\u1ea7n Tr\u00ed \u0110\u1ee9c, Th\u1ed1ng k\u00ea to\u00e1n h\u1ecdc, 1981.<\/p>\n

Summary<\/strong><\/p>\n

Bamboo block-board has been produced in Vietnam. This product is much desired on foreign market such as in Canada, the United States. However the remaining problem of this product is the hollow space along gluing line and this causes ill-effects on quality and price of the product.<\/p>\n

Though research we have found out the effect of the thickness of the bamboo and side pressing strength on the hollow gluing lines of the board.<\/p>\n

To obtain best quality of the product with least hollow gluing lines, pressure regime should be:<\/p>\n

– Max. main pressure: 18kgs\/cm2<\/sup><\/p>\n

– Max. side pressure: 6.5kg\/cm2<\/sup><\/p>\n

– Pressing temperature: 1300<\/sup>CPressing time: 11 minutes.<\/p>\n","protected":false},"excerpt":{"rendered":"

Vi\u1ec7t Nam có \u0111\u1eb7c \u0111i\u1ec3m khí h\u1eadu, \u0111\u1ea5t \u0111ai . . . r\u1ea5t phù h\u1ee3p cho tre lu\u1ed3ng sinh tr\u01b0\u1edfng và phát tri\u1ec3n. T\u1eeb m\u1ed9t cây m\u0103ng sau 3 tháng \u0111ã có m\u1ed9t cây tre tr\u01b0\u1edfng thành, ch\u1ec9 3 \u0111\u1ebfn 4 n\u0103m \u0111ã có th\u1ec3 khai thác và s\u1eed d\u1ee5ng. C\u0103n c\u1ee9 vào \u0111\u1ed9 tu\u1ed5i ng\u01b0\u1eddi ta xác \u0111\u1ecbnh \u0111\u01b0\u1ee3c \u0111\u1eb7c tính c\u1ee7a t\u1eebng \u0111\u1ed9 tu\u1ed5i:<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[],"_links":{"self":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8667"}],"collection":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/comments?post=8667"}],"version-history":[{"count":2,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8667\/revisions"}],"predecessor-version":[{"id":19253,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/posts\/8667\/revisions\/19253"}],"wp:attachment":[{"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/media?parent=8667"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/categories?post=8667"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vafs.gov.vn\/vn\/wp-json\/wp\/v2\/tags?post=8667"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}