Universidade de São Paulo

University of São Paulo is a public university in the Brazilian state of São Paulo. It ihe largest Brazilian public university and the country's most prestigious educational institution, the best university in Ibero-America,

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1 technical article »

Printed Circuit Board Recycling: Physicochemical And Economic Analysis Of Metals

Jan 05, 2022 | Marcos Paulo Kohler Caldas, Monica Maria Jiménez Correa, Flávia Paulucci Cianga Silvas, Viviane Tavares de Moraes, Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa

This study aims to present the characterization of five different types of printed circuit boards (PCBs) for use in future recycling processes. PCBs used: motherboards, lead free motherboards, video cards, memory and printer cards. The comminution of the circuit boards was performed using blade mills and hammer mills with 9mm and 6mm meshes, respectively. Throughout the physical processing, analysis was made with stereoscopic optics to ensure that the correct materials had been released. The pre-magnetic separation parts were given a granulometric classification followed by acid digestion and loss on ignition tests....

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Error Executing Database Query.

Could not create connection to database server. Attempted reconnect 3 times. Giving up.
 
The error occurred in /var/www/smtnet/dsp_global_layout.cfm: line 635
Called from /var/www/smtnet/dsp_global_layout.cfm: line 389
Called from /var/www/smtnet/dsp_global_layout.cfm: line 1
Called from /var/www/smtnet/company/dsp_layout.cfm: line 1
Called from /var/www/smtnet/company/index.cfm: line 260
Called from /var/www/smtnet/company/index.cfm: line 120
Called from /var/www/smtnet/company/index.cfm: line 11
Called from /var/www/smtnet/company/index.cfm: line 1
633 : 	 <cfset last_updated = DateAdd("n", -15, last_updated)>
634 : 	 --->
635 : 	 <cfquery datasource="user_session" name="Qonline_visitors">
636 : 		SELECT count(distinct ip) as cnt
637 : 		FROM user_session

SQLSTATE   08001
DATASOURCE   user_session
SQL    SELECT count(distinct ip) as cnt FROM user_session WHERE user_id=0 AND acceptscookies=1 AND ts_updated >= now()-interval 15 minute
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Browser   claudebot
Remote Address   44.212.94.2
Referrer  
Date/Time   29-Mar-24 09:05 AM
Stack Trace
at cfdsp_global_layout2ecfm1131192918._factor9(/var/www/smtnet/dsp_global_layout.cfm:635) at cfdsp_global_layout2ecfm1131192918._factor27(/var/www/smtnet/dsp_global_layout.cfm:389) at cfdsp_global_layout2ecfm1131192918.runPage(/var/www/smtnet/dsp_global_layout.cfm:1) at cfdsp_layout2ecfm507669117.runPage(/var/www/smtnet/company/dsp_layout.cfm:1) at cfindex2ecfm100786478._factor4(/var/www/smtnet/company/index.cfm:260) at cfindex2ecfm100786478._factor36(/var/www/smtnet/company/index.cfm:120) at cfindex2ecfm100786478._factor37(/var/www/smtnet/company/index.cfm:11) at cfindex2ecfm100786478.runPage(/var/www/smtnet/company/index.cfm:1)

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
	at sun.reflect.GeneratedConstructorAccessor917.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:395)
	at com.mysql.jdbc.Util.getInstance(Util.java:370)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:999)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:973)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:904)
	at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2369)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2290)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:818)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:31)
	at sun.reflect.GeneratedConstructorAccessor85.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:395)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
	at com.mysql.jdbc.NonRegisteringDriver.$fr$connect(NonRegisteringDriver.java:346)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java)
	at coldfusion.server.j2ee.sql.pool.JDBCPool.createPhysicalConnection(JDBCPool.java:614)
	at coldfusion.server.j2ee.sql.pool.ConnectionRunner$RunnableConnection.run(ConnectionRunner.java:67)
	at java.lang.Thread.run(Thread.java:748)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
	at sun.reflect.GeneratedConstructorAccessor917.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:395)
	at com.mysql.jdbc.Util.getInstance(Util.java:370)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:999)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:973)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1112)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2467)
	at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2308)
	... 13 more