Expressing "to adjust" with 调整 and 调节
The verbs 调整 and 调节 have a similar meaning, but they are used in different contexts.
The verb 调节
The verb 调节 
is used to talk about changes in degree or quantity.
For example: volume adjustment, height adjustment, temperature control.
is used to talk about changes in degree or quantity.
For example: volume adjustment, height adjustment, temperature control.Examples
这辆自行车车座的高度可以调节
This bike seat is height adjustable
zhè liàng zìxíngchē chēzuò de gāodù kěyǐ tiáojié
这个阀门调节水流
This valve controls the flow of water
zhè ge fámén tiáojié shuǐliú
调节灯光，使其看上去既柔和又给人以放松的感觉
Adjust the lighting so that it is soft and relaxing
tiáojié dēngguāng, shǐ qí kànshangqu jì róuhé yòu gěi rén yǐ fàngsōng de gǎnjué
The verb 调整
The verb 调整 is used to talk about changing in order to adjust to a situation and demand.
For example: price adjustment, adjustment of working hours.
is used to talk about changing in order to adjust to a situation and demand.
For example: price adjustment, adjustment of working hours.Examples
市场的动力要求有不断的变化和调整
Market dynamics requires constant changes and adjustments
shìchǎng de dònglì yāoqiú yǒu búduàn de biànhuà hé tiáozhěng
这项工作使我能够调整工作时间
This job allows me to adjust my working hours
zhè xiàng gōngzuò shǐ wǒ nénggòu tiáozhěng gōngzuò shíjiān
她可以自己快速地调整心态
She can quickly adjust her mood to fit the situation
tā kěyǐ zìjǐ kuàisù dì tiáozhěng xīntài